Anna R Dornhaus

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Chapters

• Dornhaus, A. (2014). Finding food: foraging affects all aspects of an animal’s life. In Animal Behavior, Volume II: Function and Evolution of Animal Behavior(pp 1-22).
• Charbonneau, D., Blonder, B., & Dornhaus, A. (2013). Social insects: A model system for network dynamics. In Temporal Networks(pp 217-244).
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  Abstract: Social insect colonies (ants, bees, wasps, and termites) show sophisticated collective problem-solving in the face of variable constraints. Individuals exchange information and materials such as food. The resulting network structure and dynamics can inform us about the mechanisms by which the insects achieve particular collective behaviors and these can be transposed to man-made and social networks. We discuss how network analysis can answer important questions about social insects, such as how effective task allocation or information flow is realized. We put forward the idea that network analysis methods are under-utilized in social insect research, and that they can provide novel ways to view the complexity of collective behavior, particularly if network dynamics are taken into account. To illustrate this, we present an example of network tasks performed by ant workers, linked by instances of workers switching from one task to another. We show how temporal network analysis can propose and test new hypotheses on mechanisms of task allocation, and how adding temporal elements to static networks can drastically change results.We discuss the benefits of using social insects as models for complex systems in general. There are multiple opportunities emergent technologies and analysis methods in facilitating research on social insect network. The potential for interdisciplinary work could significantly advance diverse fields such as behavioral ecology, computer sciences, and engineering. © Springer-Verlag Berlin Heidelberg 2013.
• Leonard, A. S., Dornhaus, A. R., & Papaj, D. R. (2012). Why are floral signals complex? An outline of functional hypotheses. In EVOLUTION OF PLANT-POLLINATOR RELATIONSHIPS. Cambridge University Press.
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  S. Patiny, ed.
• Leonard, A. S., Dornhaus, A. R., & Papaj, D. R. (2012). Why are floral signals complex? An outline of functional hypotheses.. In Evolution of Plant-Pollinator Relationships. Cambridge University Press.
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  S. Patiny, ed.
• Leonard, A. S., Papaj, D. R., Papaj, D. R., & Dornhaus, A. R. (2011). Why are floral signals complex? An outline of functional hypotheses. In Evolution of Plant-Pollinator Relationships. Cambridge University Press. doi:10.1017/CBO9781139014113.010
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  Introduction Plants produce a remarkable variety of displays to attract animals that transfer pollen. These floral displays are usually complex, broadcasting various combinations of visual, olfactory, gustatory, tactile, and thermal stimuli (Raguso 2004a). Even acoustic stimuli may be involved, as in the case of structural nectar guides used by echolocating flower-feeding bats (von Helversen and von Helversen 1999). Yet these sensorially complex advertisements likely evolved from an ancestor that primarily transmitted only chemicals, serving a defensive function (Pellmyr and Thein 1986). The subsequent amplification and elaboration of floral stimuli therefore offers an intriguing opportunity to study signal evolution. However, at present, we know surprisingly little about why floral displays consist of so many elements. This contrasts with progress in other areas: recently, researchers studying topics as diverse as sexual selection, warning displays, animal learning, and parent–offspring communication have explored the function of signal complexity (Rowe 1999; Candolin 2003; Hebets and Papaj 2005; Partan and Marler 2005). Researchers studying plant–pollinator interactions, however, have not to date shown a comparable degree of interest in the topic of complex signals, as judged by an analysis of the research literature. An August 2010 search on the ISI Web of Science® database on journal articles published since 1995 returned only two on plant–pollinator topics containing the words “multimodal” and “signal-” in their titles, abstracts, or keywords (those articles being Raguso and Willis 2002; Kulahci et al. 2008). In comparison, the same search returned 59 articles on sexual selection topics.
• Marshall, J., Bogacz, R., Planque, R., Dornhaus, A., Kovacs, T., & Franks, N. (2011). On optimal decision-making in brains and social insect colonies. In Modelling Natural Action Selection. Cambridge University Press.
• Dornhaus, A., & Powell, S. (2010). Foraging and defence strategies. In Ant Ecology(pp 210-230). Oxford University Press.
• Franks, N., Dornhaus, A. R., Marshall, J., & Deuchaume-Moncharmont, F. (2009). The dawn of a golden age in mathematical insect sociobiology. In Organization of Insect Societies(pp 437-459).

Journals/Publications

• Dornhaus, A., Chapin, K. J., & Kittle, A. (2022). Social pseudoscorpion nest architecture provides direct benefits to group members and rivals the efficiency of honey bees. The Journal of Arachnology, 50(3). doi:10.1636/joa-s-21-017
• Dornhaus, A., Chapin, K. J., & Paat, V. A. (2022). Brood as booty: the effect of colony size and resource value in social insect contests. Behavioral Ecology, 33(3), 549-555. doi:10.1093/beheco/arac019
• Smith, B., Dornhaus, A., Hristova, K., & Buckley, L. B. (2021). How Can We Fully Realize the Potential of Mathematical and Biological Models to Reintegrate Biology?. Integrative and Comparative Biology, 61(6), 2244-2254. doi:10.1093/icb/icab142
• Kelemen, E. P., Dornhaus, A., & Davidowitz, G. (2020). Size variation does not act as insurance in bumble bees; instead, workers add weight in an unpredictable environment. Animal Behaviour, 170, 99-109. doi:10.1016/j.anbehav.2020.10.018
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  Complex systems (e.g. eusocial insect colonies) exhibit emergent behaviours as a result of the interactions of their components. These components often vary in several traits. Such variation may improve system performance by increasing its efficiency or its robustness to environmental change. These two outcomes, efficiency and robustness, are often thought to be in opposition. Therefore, variation may be beneficial only under certain environmental conditions. Here we aim to understand why variation evolved in a particular system, bumble bee (Bombus impatiens) colonies. Workers in these colonies vary in body size, which affects the tasks they perform as well as their starvation resistance, suggesting potential impacts on efficiency and robustness, respectively. We examine how this variation affects colony performance under different environmental conditions and how colonies respond physiologically to these conditions. We maintained colonies of equal biomass but with either variable or less variable worker body sizes using targeted worker removal. We found that colonies with variable body sizes did not produce more brood (i.e. did not show evidence of increased performance) under predictable or unpredictable food environments. However, workers that developed under the unpredictable environment were smaller relative to their weight at eclosion. This effect was due in part to an increase in stored lipids, particularly in smaller workers. These physiological changes may explain why mortality rates did not differ between the predictable and unpredictable environment. Therefore, our finding that size variation did not affect colony performance suggests that size variation may be a neutral trait, present because selection is not acting against it. Our results also suggest that workers respond physiologically to differences in environmental conditions, which is important to consider when testing system robustness.
• Schraft, H. A., Montiglio, P., Dornhaus, A., Dirienzo, N., & Bradley, C. T. (2020). Foraging behavior and extended phenotype independently affect foraging success in spiders. Behavioral Ecology, 31(5), 1242-1249. doi:10.1093/beheco/araa080
• Dirienzo, N., Johnson, J. C., & Dornhaus, A. (2019). Juvenile social experience generates differences in behavioral variation but not averages.. Behavioral ecology : official journal of the International Society for Behavioral Ecology, 30(2), 455-464. doi:10.1093/beheco/ary185
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  Developmental plasticity is known to influence the mean behavioral phenotype of a population. Yet, studies on how developmental plasticity shapes patterns of variation within populations are comparatively rare and often focus on a subset of developmental cues (e.g., nutrition). One potentially important but understudied developmental experience is social experience, as it is explicitly hypothesized to increase variation among individuals as a way to promote "social niches." To test this, we exposed juvenile black widow spiders (Latrodectus hesperus) to the silk of conspecifics by transplanting them onto conspecific webs for 48 h once a week until adulthood. We also utilized an untouched control group as well as a disturbed group. This latter group was removed from their web at the same time points as the social treatment, but was immediately placed back on their own web. After repeatedly measuring adult behavior and web structure, we found that social rearing drove higher or significant levels of repeatability relative to the other treatments. Repeatability in the social treatment also decreased in some traits, paralleling the decreases observed in the disturbed treatments. Thus, repeated juvenile disturbance may decrease among-individual differences in adult spiders. Yet, social rearing appeared to override the effect of disturbance in some traits, suggesting a prioritization effect. The resulting individual differences were maintained over at least one-third of the adult lifespan and thus appear to represent stable, canalized developmental effects and not temporal state differences. These results provide proximate insight into how a broader range of developmental experiences shape trait variation.
• Kelemen, E. P., Dornhaus, A., Davidowitz, G., Cao, T., & Cao, N. (2019). Metabolic rate predicts the lifespan of workers in the bumble bee Bombus impatiens. Apidologie, 50(2), 195-203. doi:10.1007/s13592-018-0630-y
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  The rate of living theory posits that higher metabolic rates negatively affect lifespan. This relationship would influence trade-offs among life history traits associated with energy production and allocation. These trade-offs may also apply within a species, resulting in differences among individuals in life history traits. In this study, we use the bumble bee Bombus impatiens to test for a relationship between metabolic rate and lifespan. We measured the resting metabolic rates of workers throughout their lives and noted their lifespans in the laboratory. Our results show that (1) resting metabolic rate inversely correlated with potential lifespan and (2) resting metabolic rate was not affected by age. These results suggest that within a species, individual differences in life-history trade-offs may exist as predicted by the rate of living theory.
• Leitner, N., & Dornhaus, A. (2019). Dynamic task allocation: how and why do social insect workers take on new tasks?. Animal Behaviour, 158, 47-63. doi:10.1016/j.anbehav.2019.09.021
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  Complex living systems often exist in noisy environments and must have a way to respond to change. In social insects, the colony itself is a complex system composed of dozens to millions of essentially autonomous workers. Studying the behaviour of these workers in response to experimental disturbance provides insight into the mechanisms by which colonies, and complex systems in general, can achieve flexibility. Here, we explore dynamic task allocation within colonies of Temnothorax rugatulus ants by separately increasing the demand for three different types of work: nest maintenance, brood care and foraging. We investigate (1) whether colonies respond to dynamic task demand and the timeline of their responses, (2) whether the colony achieves this flexibility by recruiting new workers to these tasks or modulating individual worker effort and (3) the rules by which individual workers switch tasks. We found that T. rugatulus ants are responsive to colony perturbation, yet the means by which they achieve this flexibility are task dependent, as is the time it takes them to respond. Flexibility is achieved both by the increased effort of already active workers and the recruitment of new workers to the focal task. We suggest that newly recruited workers may come from task-specific reserve pools of unemployed workers: roaming ‘walkers’ appear to be a generalized reserve force for most tasks except for brood care, while previously inactive workers might act as a specialized reserve pool for brood care and be prompted to engage in this task when they locally encounter brood.
• Leitner, N., Leitner, N., Leitner, N. E., Gronenberg, W., Dornhaus, A., & Charbonneau, D. (2019). Peripheral sensory organs vary among ant workers but variation does not predict division of labor.. Behavioural processes, 158, 137-143. doi:10.1016/j.beproc.2018.10.016
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  The neural mechanisms underlying behavioral variation among individuals are not well understood. Differences among individuals in sensory sensitivity could limit the environmental stimuli to which an individual is capable of responding and have, indeed, been shown to relate to behavioral differences in different species. Here, we show that ant workers in Temnothorax rugatulus differ considerably in the number of antennal sensory structures, or sensilla (by 45% in density and over 100% in estimated total number). A larger quantity of sensilla may reflect a larger quantity of underlying sensory neurons. This would increase the probability that a given set of neurons in the antenna detects an environmental stimulus and becomes excited, thereby eliciting the expression of a behavior downstream at lower stimulus levels than an individual with comparatively fewer sensilla. Individual differences in antennal sensilla density, however, did not predict worker activity level or performance of any task, suggesting either that variation in sensilla density does not, in fact, reflect variation in sensory sensitivity or that individual sensory response thresholds to task-associated stimuli do not determine task allocation as is commonly assumed, at least in this social insect. More broadly, our finding that even closely related individuals can differ strongly in peripheral sensory organ elaboration suggests that such variation in sensory organs could underlie other cases of intraspecific behavioral variation.
• Leitner, N., Lynch, C., Leitner, N. E., & Dornhaus, A. (2019). Ants in isolation: obstacles to testing worker responses to task stimuli outside of the colony context. Insectes Sociaux, 66(3), 343-354. doi:10.1007/s00040-019-00692-1
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  In social insects, division of labor is commonly thought to be driven by differences among workers in their sensitivity, or response thresholds, to task-related stimuli. Despite the wide use of this mechanism throughout social insect research, actual empirical evidence for these thresholds is comparatively scarce. Here, we attempt to fill this empirical gap by testing individual task stimulus response thresholds, their consistency over time, and their relation to behavior in Temnothorax rugatulus ants. We also explored morphological differences in the antenna as one potential neural mechanism generating differences in sensitivity, and thus response threshold variation, across workers. Ants were exposed to different amounts of hungry brood, fungal spores, or sugar— stimuli that appear to drive brood care, grooming, and foraging behavior, respectively. Our measures of response thresholds were not repeatable across two trials for any of the three tested stimuli. In addition, responses to different stimulus intensities (possible response thresholds) were not associated with worker task allocation in the colony with the exception of brood care, in which case the results directly contradicted what the response threshold hypothesis predicts. Workers from different task groups also did not differ in their latency to respond to these stimuli or in the duration of their response. Sensilla density varied across workers but did not predict our measures of response thresholds to any of the tested stimuli. Though this is not what the response threshold hypothesis would have predicted, it is possible that testing ants in isolation may not accurately reflect their behavior in the colony, or that sensitivity to a task stimulus, alone, is not sufficient for driving division of labor. We suggest approaches to testing response thresholds that incorporate the roles of social context and competing task stimuli.
• Sherratt, T. N., Kikuchi, D. W., Gopeechund, V., & Dornhaus, A. (2019). Author response: Signal categorization by foraging animals depends on ecological diversity. eLife. doi:10.7554/elife.43965.013
• Sherratt, T. N., Kikuchi, D. W., Gopeechund, V., & Dornhaus, A. (2019). Signal categorization by foraging animals depends on ecological diversity.. eLife, 8. doi:10.7554/elife.43965
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  Warning signals displayed by defended prey are mimicked by both mutualistic (Müllerian) and parasitic (Batesian) species. Yet mimicry is often imperfect: why does selection not improve mimicry? Predators create selection on warning signals, so predator psychology is crucial to understanding mimicry. We conducted experiments where humans acted as predators in a virtual ecosystem to ask how prey diversity affects the way that predators categorize prey phenotypes as profitable or unprofitable. The phenotypic diversity of prey communities strongly affected predator categorization. Higher diversity increased the likelihood that predators would use a 'key' trait to form broad categories, even if it meant committing errors. Broad categorization favors the evolution of mimicry. Both species richness and evenness contributed significantly to this effect. This lets us view the behavioral and evolutionary processes leading to mimicry in light of classical community ecology. Broad categorization by receivers is also likely to affect other forms of signaling.
• Smith, C. A., Dornhaus, A., Dirienzo, N., & Bradley, C. T. (2019). Bringing down the house: male widow spiders reduce the webs of aggressive females more. Behavioral Ecology and Sociobiology, 73(2), 1-10. doi:10.1007/s00265-018-2618-z
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  Theory suggests that males should adjust courtship in response to a variety of factors, including female quality, the risk of male-male competition, and often in spiders, the risk of sexual cannibalism. Male black widow spiders demonstrate a behavior during courtship whereby they tear down and bundle a female’s web in addition to providing other vibratory and contact sexual signals. This web reduction has been hypothesized to play a role in all three factors (sexual signaling, competition reduction, and cannibalism reduction), but rarely are these tested together. Here, we test these hypotheses by conducting mating trials using the western black widow (Latrodectus hesperus) and measuring both male and female quality and behavior. Our results indicate that amount of web reduction is best predicted by female aggression, and not aspects of either male or female quality (e.g., body mass), or by the potential for the web to attract other males (e.g., web mass). Yet, actual mating success was best predicted by the proportion of web reduced. Furthermore, there was no consistent among-individual variation in either reduction behavior or male success, indicating that all variation in both measures was due to plasticity and/or other unaccounted-for male or female traits. Collectively, we conclude that the primary function of web reduction behavior is to reduce female aggression and thus the risk of sexual cannibalism, and that any other functions such as signaling and reducing male-male competition have relatively lower importance. Male widow spiders must account for female aggression, quality, and male-male competition when courting females. During courtship, males will reduce a female’s web by tearing it down and bundling the silk, which may aid in all three of these issues. Our results demonstrate that males reduce the webs of aggressive females more, and less so to potentially reduce competition from other males or in response to female quality. Ultimate mating success was dictated by how much a male reduced the web of a given female. Finally, males showed no among-individual variation in reduction behavior, indicating that the extensive variation in this behavior is due solely to plasticity in response to the female.
• Walton, A., Jandt, J. M., & Dornhaus, A. (2019). Guard bees are more likely to act as undertakers: variation in corpse removal in the bumble bee Bombus impatiens. Insectes Sociaux, 66(4), 533-541. doi:10.1007/s00040-019-00718-8
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  Task specialization is one of the distinguishing features of social insect colony organization. Here we study the task of corpse removal (‘undertaking’) from the nest in three Bombus impatiens colonies. We determine (1) which task these bees perform when corpses are absent from the nest; (2) the degree to which worker body size relates to undertaking behavior; and (3) whether certain bees are more likely to completely remove corpses (i.e., are better undertakers)? We found that only ~ 31% of the workers in a colony participated in corpse removal even when corpses were abundant (and only ~ 12% participated in more than one trial, i.e., were “repeat undertakers”). Larger bees, and those that engaged in guarding tasks when corpses were absent, were more likely to perform undertaking. In addition, repeat undertakers, who were not necessarily larger than one-trial undertakers, were more successful at removing corpses and invested more effort per trial. Overall, our results are consistent with the interpretation that workers who are more likely to engage in guarding tasks (who also tend to be larger and patrol throughout the nest) may be more vigilant and sensitive to changes in the chemical nature of the nest, and so will also perform undertaking when it becomes necessary.
• Kelemen, E. P., & Dornhaus, A. (2018). Lower temperatures decrease worker size variation but do not affect fine-grained thermoregulation in bumble bees. Behavioral Ecology and Sociobiology, 72(10). doi:10.1007/s00265-018-2577-4
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  Phenotypic variation within biological systems is ubiquitous and often assumed to be adaptive in social insects. Local environmental factors, such as temperature, may affect the phenotypic variation produced, and yield insights into the mechanisms that generate this group-level outcome. For instance, fine-scale heterogeneity in temperature across the nest may generate phenotypic variation by affecting larval development directly, or indirectly by inducing changes in the behavior of group members. To understand the role of temperature in producing phenotypic variation, we studied whether microclimatic differences within the nest could produce the worker size variation commonly observed in bumble bee (Bombus impatiens) colonies. We also tested if changes to the ambient temperature that colonies are exposed to influences the size variation they produced. We recorded brood temperature via thermal imaging and measured thorax widths of workers produced by colonies kept at ambient temperatures of 30 and 20 °C. Overall, average brood temperature did not differ across the nest even while the average temperature of non-brood structures (i.e., honeypots) interspersed among the brood decreased towards the periphery, demonstrating that bees were able to regulate brood temperature at a fine scale. However, we found that the size variation produced was sensitive to ambient temperature and increased under warmer temperatures. These results demonstrate that bumble bees have a unique method of fine-grained thermoregulation, where they regulate brood temperature but not the regions between brood. Additionally, while temperature is not the mechanism that produces size variation, it indirectly influences the mechanism that does. Morphological variation among group members affects group performance. We studied how the thermal environment experienced by developing workers, i.e., brood, influences the between-worker size variation produced within B. impatiens colonies. We found that temperature only indirectly influences size variation, as size variation increased under warmer nest temperatures, yet the temperature of brood did not differ across the nest. Our finding that workers maintain a uniform environment for the brood differs from previous results examining feeding rates across the nest and suggests that while the same workers tend to feed and thermoregulate the brood, they do so according to different rules and that by influencing worker behaviors, such as feeding rate, temperature affects size variation.
• Leitner, N., Gronenberg, W., Charbonneau, D., & Dornhaus, A. R. (2018). Peripheral sensory organs vary among ant workers but variation does not predict division of labor.. Animal Behavior.
• Muth, F., Dornhaus, A., Bronstein, J. L., & Barker, J. L. (2018). Learning about larceny: experience can bias bumble bees to rob nectar. Behavioral Ecology and Sociobiology, 72(4). doi:10.1007/s00265-018-2478-6
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  How do nectar-feeding animals choose among alternative flower-handling tactics? Such decisions have consequences not only for animal fitness (via food intake) but for plant fitness as well: many animals can choose to “rob” nectar through holes chewed in the base of a flower instead of “legitimately” collecting it through the flower’s opening, thus failing to contact pollen. Although variation within a species in these nectar-foraging tactics is well documented, it is largely unknown why some individuals specialize (at least in the short term) on robbing, others on legitimate visitation, and others switch between these behaviors. We investigated whether the tendency to rob nectar through previously-made holes (secondary robbing) is influenced by prior foraging experience. In a laboratory experiment, we trained groups of bumble bees (Bombus impatiens) either to visit artificial flowers legitimately or to secondary-rob; a third group received no training. On subsequent visits to flowers, all bees had the opportunity to use either foraging tactic. We found that experience did affect bees’ tendency to secondary-rob: trained bees were more likely to adopt the tactic they had previously experienced. Untrained bees initially sampled both tactics, but over time preferred to secondary-rob. Experience also increased bees’ success at gaining nectar from flowers, but only when visiting flowers legitimately (the less preferred tactic). Overall, these findings highlight the importance of experience in animals’ choices of alternative handling tactics while foraging and help explain long-standing observations of variation in nectar-robbing behavior among individuals of the same population. Animals that can adopt alternative behaviors frequently use only one of them. A widespread but little understood example of this is nectar feeding, in which foragers can choose between “legitimately” collecting nectar through a flower’s opening or “robbing” nectar via holes chewed through a flower’s base. We showed in a laboratory experiment that prior foraging experience can bias bumble bees’ choices to rob nectar from pre-existing holes (i.e., to “secondary”-rob). Initial exposure to flowers that could only be robbed or only be legitimately visited increased bees’ tendency to subsequently adopt that behavior at the expense of sampling the alternative behavior, even when other bees seemed to prefer the alternative. These results help explain field observations that bees often specialize on a single nectar-collecting behavior and that there is individual variation in which behavior is adopted, contributing to our understanding of nectar robbing from the animals’ perspective.
• Bengston, S. E., Shin, M. C., Dornhaus, A., & Bengston, S. E. (2017). Life‐history strategy and behavioral type: risk‐tolerance reflects growth rate and energy allocation in ant colonies. Oikos, 126(4), 556-564. doi:10.1111/oik.03527
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  Despite the recent interest in animal personality and behavioral syndromes, there is a paucity of explanations for why distinct behavioral traits should evolve to correlate. We investigate whether such correlations across apparently distinct behavioral traits may be explained by variation in life history strategy among individual ant colonies. Life history theory predicts that the way in which individuals allocate energy towards somatic maintenance or reproduction drives several distinct traits in physiology, morphology, and energy use; it also predicts that an individual's willingness to engage in risky behaviors should depend on reproductive strategy. We use Temnothorax ants, which have been shown to exhibit ‘personalities’ and a syndrome that may reflect risk tolerance at the colony level. We measure colonies' relative investment in growth rate (new workers produced) compared to reproductive effort (males and queens produced). Comparing sterile worker production to reproductive alate production provides a direct measure of how colonies are investing their energy, analogous to investment in growth versus reproduction in a unitary organism. Consistently with this idea, we found that behavioral type of ant colonies was associated with their life history strategy: risk-tolerant colonies grew faster and invested more in reproduction, whereas risk-averse colonies had lower growth rate but invested relatively more in workers. This provides evidence that behavioral syndromes can be a consequence of life-history strategy variation, linking the two fields and supporting the use of an integrative approach.
• Dornhaus, A. R., Gutenkunst, R. N., Wang, X., & Leighton, G. M. (2017). Behavioral caste is associated with distinct gene expression profiles in workers in Temnothorax rugatulus. BMC Genomics.
• Dornhaus, A., & Dirienzo, N. (2017). Temnothorax rugatulus ant colonies consistently vary in nest structure across time and context.. PloS one, 12(6), e0177598. doi:10.1371/journal.pone.0177598
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  A host of animals build architectural constructions. Such constructions frequently vary with environmental and individual/colony conditions, and their architecture directly influences behavior and fitness. The nests of ant colonies drive and enable many of their collective behaviors, and as such are part of their 'extended phenotype'. Since ant colonies have been recently shown to differ in behavior and life history strategy, we ask whether colonies differ in another trait: the architecture of the constructions they create. We allowed Temnothorax rugatulus rock ants, who create nests by building walls within narrow rock gaps, to repeatedly build nest walls in a fixed crevice but under two environmental conditions. We find that colonies consistently differ in their architecture across environments and over nest building events. Colony identity explained 12-40% of the variation in nest architecture, while colony properties and environmental conditions explained 5-20%, as indicated by the condition and marginal R2 values. When their nest boxes were covered, which produced higher humidity and lower airflow, colonies built thicker, longer, and heavier walls. Colonies also built more robust walls when they had more brood, suggesting a protective function of wall thickness. This is, to our knowledge, the first study to explicitly investigate the repeatability of nestbuilding behavior in a controlled environment. Our results suggest that colonies may face tradeoffs, perhaps between factors such as active vs. passive nest defense, and that selection may act on individual construction rules as a mechanisms to mediate colony-level behavior.
• Leighton, G. M., Dornhaus, A., & Charbonneau, D. (2017). Task switching is associated with temporal delays in Temnothorax rugatulus ants.. Behavioral ecology : official journal of the International Society for Behavioral Ecology, 28(1), 319-327. doi:10.1093/beheco/arw162
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  The major evolutionary transitions often result in reorganization of biological systems, and a component of such reorganization is that individuals within the system specialize on performing certain tasks, resulting in a division of labor. Although the traditional benefit of division of labor is thought to be a gain in work efficiency, one alternative benefit of specialization is avoiding temporal delays associated with switching tasks. While models have demonstrated that costs of task switching can drive the evolution of division of labor, little empirical support exists for this hypothesis. We tested whether there were task-switching costs in Temnothorax rugatulus. We recorded the behavior of every individual in 44 colonies and used this dataset to identify each instance where an individual performed a task, spent time in the interval (i.e., inactive, wandering inside, and self-grooming), and then performed a task again. We compared the interval time where an individual switched task type between that first and second bout of work to instances where an individual performed the same type of work in both bouts. In certain cases, we find that the interval time was significantly shorter if individuals repeated the same task. We find this time cost for switching to a new behavior in all active worker groups, that is, independently of worker specialization. These results suggest that task-switching costs may select for behavioral specialization.
• Papaj, D. R., Dunlap, A. S., & Dornhaus, A. (2017). Sampling and tracking a changing environment: persistence and reward in the foraging decisions of bumblebees.. Interface focus, 7(3), 20160149. doi:10.1098/rsfs.2016.0149
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  The question of when to collect new information and how to apply that information is central to much of behaviour. Theory suggests that the value of collecting information, or sampling, depends on environmental persistence and on the relative costs of making wrong decisions. However, empirical tests of how these variables interact are lacking. We tested whether bumblebee foraging decisions are indeed influenced by these two factors. We gave bees repeated choices between a resource providing a steady, mediocre reward and a resource fluctuating between a low reward and a high reward. In this paradigm, we manipulated environmental persistence by changing how long the quality of a fluctuating resource remained stable at one reward level. We manipulated the costs of decision errors by changing the relative values of the available rewards. Bees sampled the fluctuating resource more frequently when it changed quality more frequently, indicating that they measured environmental persistence and reacted to it as predicted by theory. Bees showed surprisingly suboptimal tracking, not reliably choosing the currently best resource except when the fluctuating resource was very persistent and the potential rewards high. While bees modify their choices in response to different levels of change and potential rewards, they do not always do so according to optimality predictions.
• Sasaki, T., Dornhaus, A., & Charbonneau, D. (2017). Who needs 'lazy' workers? Inactive workers act as a 'reserve' labor force replacing active workers, but inactive workers are not replaced when they are removed.. PloS one, 12(9), e0184074. doi:10.1371/journal.pone.0184074
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  Social insect colonies are highly successful, self-organized complex systems. Surprisingly however, most social insect colonies contain large numbers of highly inactive workers. Although this may seem inefficient, it may be that inactive workers actually contribute to colony function. Indeed, the most commonly proposed explanation for inactive workers is that they form a 'reserve' labor force that becomes active when needed, thus helping mitigate the effects of colony workload fluctuations or worker loss. Thus, it may be that inactive workers facilitate colony flexibility and resilience. However, this idea has not been empirically confirmed. Here we test whether colonies of Temnothorax rugatulus ants replace highly active (spending large proportions of time on specific tasks) or highly inactive (spending large proportions of time completely immobile) workers when they are experimentally removed. We show that colonies maintained pre-removal activity levels even after active workers were removed, and that previously inactive workers became active subsequent to the removal of active workers. Conversely, when inactive workers were removed, inactivity levels decreased and remained lower post-removal. Thus, colonies seem to have mechanisms for maintaining a certain number of active workers, but not a set number of inactive workers. The rapid replacement (within 1 week) of active workers suggests that the tasks they perform, mainly foraging and brood care, are necessary for colony function on short timescales. Conversely, the lack of replacement of inactive workers even 2 weeks after their removal suggests that any potential functions they have, including being a 'reserve', are less important, or auxiliary, and do not need immediate recovery. Thus, inactive workers act as a reserve labor force and may still play a role as food stores for the colony, but a role in facilitating colony-wide communication is unlikely. Our results are consistent with the often cited, but never yet empirically supported hypothesis that inactive workers act as a pool of 'reserve' labor that may allow colonies to quickly take advantage of novel resources and to mitigate worker loss.
• Shin, M. C., Poff, C., Nguyen, H., Kierstead, K., Dornhaus, A., & Charbonneau, D. (2017). Who Are the "Lazy" Ants? The Function of Inactivity in Social Insects and a Possible Role of Constraint: Inactive Ants Are Corpulent and May Be Young and/or Selfish.. Integrative and comparative biology, 57(3), 649-667. doi:10.1093/icb/icx029
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  Social insect colonies are commonly thought of as highly organized and efficient complex systems, yet high levels of worker inactivity are common. Although consistently inactive workers have been documented across many species, very little is known about the potential function or costs associated with this behavior. Here we ask what distinguishes these "lazy" individuals from their nestmates. We obtained a large set of behavioral and morphological data about individuals, and tested for consistency with the following evolutionary hypotheses: that inactivity results from constraint caused by worker (a) immaturity or (b) senescence; that (c) inactive workers are reproducing; that inactive workers perform a cryptic task such as (d) acting as communication hubs or (e) food stores; and that (f) inactive workers represent the "slow-paced" end of inter-worker variation in "pace-of-life." We show that inactive workers walk more slowly, have small spatial fidelity zones near the nest center, are more corpulent, are isolated in colony interaction networks, have the smallest behavioral repertoires, and are more likely to have oocytes than other workers. These results are consistent with the hypotheses that inactive workers are immature and/or storing food for the colony; they suggest that workers are not inactive as a consequence of senescence, and that they are not acting as communication hubs. The hypotheses listed above are not mutually exclusive, and likely form a "syndrome" of behaviors common to inactive social insect workers. Their simultaneous contribution to inactivity may explain the difficulty in finding a simple answer to this deceptively simple question.
• Su, H., Radeva, T., Nagpal, R., Lynch, N., & Dornhaus, A. (2017). Costs of task allocation with local feedback: Effects of colony size and extra workers in social insects and other multi-agent systems.. PLoS computational biology, 13(12), e1005904. doi:10.1371/journal.pcbi.1005904
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  Adaptive collective systems are common in biology and beyond. Typically, such systems require a task allocation algorithm: a mechanism or rule-set by which individuals select particular roles. Here we study the performance of such task allocation mechanisms measured in terms of the time for individuals to allocate to tasks. We ask: (1) Is task allocation fundamentally difficult, and thus costly? (2) Does the performance of task allocation mechanisms depend on the number of individuals? And (3) what other parameters may affect their efficiency? We use techniques from distributed computing theory to develop a model of a social insect colony, where workers have to be allocated to a set of tasks; however, our model is generalizable to other systems. We show, first, that the ability of workers to quickly assess demand for work in tasks they are not currently engaged in crucially affects whether task allocation is quickly achieved or not. This indicates that in social insect tasks such as thermoregulation, where temperature may provide a global and near instantaneous stimulus to measure the need for cooling, for example, it should be easy to match the number of workers to the need for work. In other tasks, such as nest repair, it may be impossible for workers not directly at the work site to know that this task needs more workers. We argue that this affects whether task allocation mechanisms are under strong selection. Second, we show that colony size does not affect task allocation performance under our assumptions. This implies that when effects of colony size are found, they are not inherent in the process of task allocation itself, but due to processes not modeled here, such as higher variation in task demand for smaller colonies, benefits of specialized workers, or constant overhead costs. Third, we show that the ratio of the number of available workers to the workload crucially affects performance. Thus, workers in excess of those needed to complete all tasks improve task allocation performance. This provides a potential explanation for the phenomenon that social insect colonies commonly contain inactive workers: these may be a 'surplus' set of workers that improves colony function by speeding up optimal allocation of workers to tasks. Overall our study shows how limitations at the individual level can affect group level outcomes, and suggests new hypotheses that can be explored empirically.
• Woodrow-tomizuka, A., Powell, S., Dornhaus, A., & Donaldson-matasci, M. C. (2017). Context‐dependent defences in turtle ants: Resource defensibility and threat level induce dynamic shifts in soldier deployment. Functional Ecology, 31(12), 2287-2298. doi:10.1111/1365-2435.12926
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  Induced defences involve the dynamic deployment of limited and specialized defensive resources across multiple locations, to maximize organismal defensive function and fitness. They have been studied intensively in plants and solitary animals, but the induced defences of complex animal societies are poorly understood by comparison, despite the coordinated defensive actions of these taxa. Here, we ask whether the level of environmental danger induces shifts in the deployment of limited and morphologically specialized soldiers across multiple nests in colonies of the turtle ant Cephalotes rohweri. Specifically, we test whether less defensible nests induce greater soldier deployment, and whether elevated enemy threat induced further increases in deployment, or reduced deployment consistent with a risk-limiting strategy. We used colony-collection data to provide natural ecological context to our experiments, a field experiment to address how nest-entrance defensibility and soldier number impact defensive performance, and laboratory experiments to test whether differences in nest defensibility and threat level induce dynamic shifts in soldier deployment to new nests. Less defensible nests were lost rapidly in our field experiment, irrespective of soldier number, but soldier deployment significantly increased survivorship of more defensible nests. Concordantly, less defensible nests induced the deployment of more soldiers per nest under low threat in laboratory experiments. Nevertheless, high-threat conditions revealed a risk-limiting soldier deployment strategy: with more danger, the number of soldiers per nest was significantly reduced in less defensible nests, as was the overall number of new soldier-defended nests. Total deployment to new nests was also consistently lower under high threat, dropping from 40% to 30% of all available soldiers across colonies. Induced soldier-based defences in turtle ants are therefore context-dependent, and dynamically scaled back at multiple levels when the environment is more dangerous. This dynamic, risk-limiting strategy is in strong contrast to stable patterns of soldier production in ants, and to typical task-allocation dynamics in members of the worker caste. Moreover, these findings establish that the evolution of specialized defensive agents can be coupled with sophisticated and inducible deployment strategies in complex social taxa, as we see for organisms at other levels of biological complexity. plain language summary is available for this article.
• Dornhaus, A. R., Cao, N., Cao, T., Davidowitz, G., & Kelemen, E. (2018). Metabolic rate is consistent with age and predicts the lifespan of the bumble bee Bombus impatiens. Biology Letters.
• Dunlap, A. S., Nielsen, M. E., Dornhaus, A. R., & Papaj, D. R. (2016). Foraging bumble bees weigh the reliability of personal and social information. CURRENT BIOLOGY.
• Bengston, S., & Dornhaus, A. R. (2015). Latitudinal variation in behaviors linked to risk-tolerance is driven by nest-site competition and spatial distribution in the ant Temnothorax rugatulus. Behavioral Ecology and Sociobiology, 69, 1265-1274.
• Charbonneau, D., & Dornhaus, A. (2015). When doing nothing is something. How task allocation strategies compromise between flexibility, efficiency, and inactive agents. Journal of Bioeconomics, 17, 217-242.
• Charbonneau, D., & Dornhaus, A. R. (2015). Workers 'specialized' on inactivity: behavioral consistency of inactive workers and their role in task allocation. Behavioral Ecology and Sociobiology.
• Rivera, M., Donaldson-Matasci, M., & Dornhaus, A. R. (2015). Quitting time: When do honey bee foragers decide to stop foraging on natural resources?. Frontiers in Ecology and Evolution, 3, 50.
• Cornejo, A., Dornhaus, A., Lynch, N., & Nagpal, R. (2014). Task Allocation in Ant Colonies. Distributed Computing – Lecture Notes in Computer Science, 8784, 46-60.
• Donaldson-Matasci, M., & Dornhaus, A. (2014). Dance Communication Affects Consistency, but Not Breadth, of Resource Use in Pollen-Foraging Honey Bees. PLOS One, 9, e107527.
• Jandt, J. M., Bengston, S., Pinter-Wollman, N., Pruitt, J. N., Raine, N. E., Dornhaus, A., & Sih, A. (2014). Behavioural syndromes and social insects: Personality at multiple levels. Biological Reviews, 89(1), 48-67.
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  Abstract: Animal personalities or behavioural syndromes are consistent and/or correlated behaviours across two or more situations within a population. Social insect biologists have measured consistent individual variation in behaviour within and across colonies for decades. The goal of this review is to illustrate the ways in which both the study of social insects and of behavioural syndromes has overlapped, and to highlight ways in which both fields can move forward through the synergy of knowledge from each. Here we, (i) review work to date on behavioural syndromes (though not always referred to as such) in social insects, and discuss mechanisms and fitness effects of maintaining individual behavioural variation within and between colonies; (ii) summarise approaches and principles from studies of behavioural syndromes, such as trade-offs, feedback, and statistical methods developed specifically to study behavioural consistencies and correlations, and discuss how they might be applied specifically to the study of social insects; (iii) discuss how the study of social insects can enhance our understanding of behavioural syndromes-research in behavioural syndromes is beginning to explore the role of sociality in maintaining or developing behavioural types, and work on social insects can provide new insights in this area; and (iv) suggest future directions for study, with an emphasis on examining behavioural types at multiple levels of organisation (genes, individuals, colonies, or groups of individuals). © 2013 Cambridge Philosophical Society.
• Westling, J. N., Harrington, K., Bengston, S., & Dornhaus, A. (2014). Morphological differences between extranidal and intranidal workers in the ant Temnothorax rugatulus, but no effect of body size on foraging distance. Insectes sociaux, 61, 367-369.
• Bengston, S. E., & Dornhaus, A. (2013). Colony size does not predict foraging distance in the ant Temnothorax rugatulus: A puzzle for standard scaling models. Insectes Sociaux, 60(1), 93-96.
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  Abstract: Body size is often positively correlated with ecologically relevant traits such as fecundity, survival, resource requirements, and home range size. Ant colonies, in some respects, behave like organisms, and their colony size is thought to be a significant predictor of many behavioral and ecological traits similar to body size in unitary organisms. In this study, we test the relationship between colony size and field foraging distance in the ant species Temnothorax rugatulus. These ants forage in the leaf litter presumably for small arthropod prey. We found colonies did not differ significantly in their foraging distances, and colony size is not a significant predictor of foraging distance. This suggests that large colonies may not exhaust local resources or that foraging trips are not optimized for minimal distance, and thus that food may not be the limiting resource in this species. This study shows T. rugatulus are behaving in ways that differ from existing models of scaling. © 2012 International Union for the Study of Social Insects (IUSSI).
• Cao, T. T., & Dornhaus, A. (2013). Larger laboratory colonies consume proportionally less energy and have lower per capita brood production in Temnothorax ants. Insectes Sociaux, 60(1), 1-5.
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  Abstract: Colony size can affect individual- and colony-level behavioral and physiological traits in social insects. Changes in behavior and physiology in response to colony growth and development can affect productivity and fitness. Here, we used respirometry to study the relationship between colony size and colony energy consumption in Temnothorax rugatulus ants. In addition, we examined the relationship between colony size and worker productivity measured as per capita brood production. We found that colony metabolic rate scales with colony size to the 0. 78 power and the number of brood scales with the number of workers to the 0. 49 power. These regression analyses reveal that larger ant colonies use proportionally less energy and produce fewer brood per worker. Our findings provide new information on the relationships between colony size and energetic efficiency and productivity in a model ant genus. We discuss the potential mechanisms giving rise to allometric scaling of metabolic rate in ant colonies and the influence of colony size on energy consumption and productivity in general. © 2012 International Union for the Study of Social Insects (IUSSI).
• Donaldson-Matasci, M. C., DeGrandi-Hoffman, G., & Dornhaus, A. (2013). Bigger is better: Honeybee colonies as distributed information-gathering systems. Animal Behaviour, 85(3), 585-592.
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  Abstract: In collectively foraging groups, communication about food resources can play an important role in the organization of the group's activity. For example, the honeybee dance communication system allows colonies to selectively allocate foragers among different floral resources according to their quality. Because larger groups can potentially collect more information than smaller groups, they might benefit more from communication because it allows them to integrate and use that information to coordinate forager activity. Larger groups might also benefit more from communication because it allows them to dominate high-value resources by recruiting large numbers of foragers. By manipulating both colony size and the ability to communicate location information in the dance, we show that larger colonies of honeybees benefit more from communication than do smaller colonies. In fact, colony size and dance communication worked together to improve foraging performance; the estimated net gain per foraging trip was highest in larger colonies with unimpaired communication. These colonies also had the earliest peaks in foraging activity, but not the highest ones. This suggests they may find and recruit to resources more quickly, but not more heavily. The benefits of communication we observed in larger colonies are thus likely a result of more effective information-gathering due to massive parallel search rather than increased competitive ability due to heavy recruitment. © 2013 The Association for the Study of Animal Behaviour.
• Dornhaus, A., Bengston, S., Jandt, J. M., Pinter-Wollman, N., Pruitt, J. N., Raine, N. E., & Sih, A. (2013). Behavioural syndromes and social insects: personality at multiple levels. Biological Reviews, 89(1), 48-67. doi:10.1111/brv.12042
• Fasciano, T., Nguyen, H., Dornhaus, A., & Shin, M. C. (2013). Tracking multiple ants in a colony. Proceedings of IEEE Workshop on Applications of Computer Vision, 534-540.
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  Abstract: The automated tracking of social insects, such as ants, could dramatically increase the fidelity and amount of analyzed data for studying complex group behaviors. Recently, data association based multiple object tracking methods have shown promise in improving handling of occlusions. However, the tracking of ants in a colony is still challenging as (1) their motion is often sporadic and irregular and (2) they are mostly present the entire duration of video. In this paper, we propose to improve the data association based tracking of multiple ants. First, we model the ant's motion using a set of irregular motion features including random walk model. Second, we use the convergence of particle filter based tracking to match tracklets with a long temporal gap. Testing results of two-fold cross validation on a 10,000 frame video shows that our proposed method was able to reduce the number of fragments by 61% and ID switches by 57%. © 2013 IEEE.
• Leonard, A. S., Brent, J., Papaj, D. R., & Dornhaus, A. (2013). Floral nectar guide patterns discourage nectar robbing by bumble bees. PLOS ONE, 8(2), e55914.
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  featured in PLoS Author SpotlightPMID: 23418475;PMCID: PMC3572167;Abstract: Floral displays are under selection to both attract pollinators and deter antagonists. Here we show that a common floral trait, a nectar guide pattern, alters the behavior of bees that can act opportunistically as both pollinators and as antagonists. Generally, bees access nectar via the floral limb, transporting pollen through contact with the plant's reproductive structures; however bees sometimes extract nectar from a hole in the side of the flower that they or other floral visitors create. This behavior is called "nectar robbing" because bees may acquire the nectar without transporting pollen. We asked whether the presence of a symmetric floral nectar guide pattern on artificial flowers affected bumble bees' (Bombus impatiens) propensity to rob or access nectar "legitimately." We discovered that nectar guides made legitimate visits more efficient for bees than robbing, and increased the relative frequency of legitimate visits, compared to flowers lacking nectar guides. This study is the first to show that beyond speeding nectar discovery, a nectar guide pattern can influence bees' flower handling in a way that could benefit the plant. © 2013 Leonard et al.
• Leonard, A. S., Brent, J., Papaj, D. R., & Dornhaus, A. (2013). Floral nectar guide patterns discourage nectar robbing by bumble bees. PLoS ONE, 8(2), e55914.
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  featured in PLoS Author SpotlightPMID: 23418475;PMCID: PMC3572167;Abstract: Floral displays are under selection to both attract pollinators and deter antagonists. Here we show that a common floral trait, a nectar guide pattern, alters the behavior of bees that can act opportunistically as both pollinators and as antagonists. Generally, bees access nectar via the floral limb, transporting pollen through contact with the plant's reproductive structures; however bees sometimes extract nectar from a hole in the side of the flower that they or other floral visitors create. This behavior is called "nectar robbing" because bees may acquire the nectar without transporting pollen. We asked whether the presence of a symmetric floral nectar guide pattern on artificial flowers affected bumble bees' (Bombus impatiens) propensity to rob or access nectar "legitimately." We discovered that nectar guides made legitimate visits more efficient for bees than robbing, and increased the relative frequency of legitimate visits, compared to flowers lacking nectar guides. This study is the first to show that beyond speeding nectar discovery, a nectar guide pattern can influence bees' flower handling in a way that could benefit the plant. © 2013 Leonard et al.
• Powell, S., & Dornhaus, A. (2013). Soldier-based defences dynamically track resource availability and quality in ants. Animal Behaviour, 85(1), 157-164.
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  Abstract: Specialized defence traits and strategies are crucial in surviving enemy attacks and in resource acquisition. In numerous social insect lineages, soldiers function as specialized defence traits of the colony, but associated defence strategies are poorly known. The turtle ant Cephalotes rohweri is an obligate cavity-nesting ant with highly specialized soldiers. To maximize growth and reproduction, colonies must use their limited availability of soldiers to defend multiple cavities. Using laboratory experiments informed by field data, we addressed how soldier 'deployment' across cavities adjusts to changes in cavity availability and quality. From initial field-like conditions, soldier deployment to newly available cavities was rapid, stabilized quickly, and at least doubled the number of cavities defended by each colony. New cavities were defended by fewer soldiers than original cavities still in use. Nevertheless, when new cavities differed in size, an important quality metric, large cavities were used more often and defended by more soldiers than small cavities. Despite these dynamic responses, total soldier deployment to new cavities was limited to an approximately constant proportion (0.4) of overall soldier availability across colonies and resource contexts. Moreover, there was a significant positive relationship between total soldier deployment to new cavities (greater for larger colonies) and both the number of newly defended cavities and their average level of defence. These results demonstrate that colony-wide soldier deployment is dynamic, predictable and context sensitive but ultimately constrained by the availability of soldiers in the colony. Furthermore, the consistently lower number of soldiers in new cavities, which always limits the potential losses to enemies, is concordant with a 'conservative bet-hedging' life history strategy. Broadly, our findings show that a specialized soldier caste can be associated with a far more sophisticated defence strategy than previously recognized. This provides a more complete perspective on the evolution of soldier-based defences in insect societies. © 2012 The Association for the Study of Animal Behaviour.
• Blonder, B., Wey, T. W., Dornhaus, A., James, R., & Sih, A. (2012). Temporal dynamics and network analysis. Methods in Ecology and Evolution, 3(6), 958-972.
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  Abstract: 1. Network analysis is widely used in diverse fields and can be a powerful framework for studying the structure of biological systems. Temporal dynamics are a key issue for many ecological and evolutionary questions. These dynamics include both changes in network topology and flow on the network. Network analyses that ignore or do not adequately account for the temporal dynamics can result in inappropriate inferences. 2. We suggest that existing methods are currently under-utilized in many ecological and evolutionary network analyses and that the broader incorporation of these methods will considerably advance the current field. Our goal is to introduce ecologists and evolutionary biologists interested in studying network dynamics to extant ideas and methodological approaches, at a level appropriate for those new to the field. 3. We present an overview of time-ordered networks, which provide a framework for analysing network dynamics that addresses multiple inferential issues and permits novel types of temporally informed network analyses. We review available methods and software, discuss the utility and considerations of different approaches, provide a worked example analysis and highlight new research opportunities in ecology and evolutionary biology. Blog © 2012 The Authors. Methods in Ecology and Evolution © 2012 British Ecological Society.
• Cao, T. T., & Dornhaus, A. (2012). Ants use pheromone markings in emigrations to move closer to food-rich areas. Insectes Sociaux, 59(1), 87-92.
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  Abstract: Nest site quality can affect survival and reproduction, and thus many animals have evolved behaviors which facilitate nest site assessment and selection. Ants of the genus Temnothorax have been shown to include an array of nest site attributes when choosing such a site. Here, we show that they also include traits of the habitat surrounding nest sites. In particular, we found that during emigration, ants preferred to move to nests located close to a previously explored food-rich area. We also determined that scent markings played a role in this choice and that scouts and transporting ants may have tracked scent marks laid in foraging, and this behavior could have biased emigration toward nests located near previously foraged areas. These results indicate that pheromones play a bigger role in Temnothorax foraging and decision making in emigration than previously thought. Overall, this work provides new insights into the mechanisms involved in habitat selection in ants and contributes to our understanding of collective behavior in social insects in general. © 2011 International Union for the Study of Social Insects (IUSSI).
• Donaldson-Matasci, M. C., & Dornhaus, A. (2012). Erratum to How habitat affects the benefits of communication in collectively foraging honey bees (Behav Ecol Sociobiol, 10.1007/s00265-011-1306-z). Behavioral Ecology and Sociobiology, 66(6), 993-.
• Donaldson-Matasci, M. C., & Dornhaus, A. (2012). How habitat affects the benefits of communication in collectively foraging honey bees. Behavioral Ecology and Sociobiology, 66(4), 583-592.
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  Abstract: Honey bees (Apis mellifera) use the dance language to symbolically convey information about the location of floral resources from within the nest. To figure out why this unique ability evolved, we need to understand the benefits it offers to the colony. Previous studies have shown that, in fact, the location information in the dance is not always beneficial. We ask, in which ecological habitats do honey bee colonies actually benefit from the dance language, and what is it about those habitats that makes communication useful? In this study, we examine the effects of floral distribution patterns on the benefits of dance communication across five different habitats. In each habitat, we manipulated colonies' ability to communicate and measured their foraging success, while simultaneously characterizing the naturally occurring floral distribution. We find that communication is most beneficial when floral species richness is high and patches contain many flowers. These are ecological features that could have helped shape the evolution of the honey bee dance language. © 2012 Springer-Verlag.
• Dornhaus, A. (2012). Finding optimal collective strategies using individual-based simulations: colony organization in social insects. Mathematical and Computer Modelling of Dynamical Systems, 18(1), 25-37.
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  Abstract: Social insects like ants and bees live in cooperative colonies containing up to millions of individuals. These colonies are sometimes termed 'superorganisms' and have evolved tightly integrated and sophisticated collective behaviours. Different species, however, often differ in the type and mechanisms of communication and collective organization employed. I show here how individual-based models can be used to identify the non-intuitive benefits of different mechanisms of communication and division of labour and how these benefits may depend on the external environment as well as traits of the society itself. This allows us to understand under what ecological conditions particular types of collective organization may have evolved, and thus can also help to explain variation among species. © 2012 Copyright Taylor and Francis Group, LLC.
• Dornhaus, A., Powell, S., & Bengston, S. (2012). Group size and its effects on collective organization. Annual Review of Entomology, 57, 123-141.
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  PMID: 21888521;Abstract: Many insects and arthropods live in colonies or aggregations of varying size. Group size may affect collective organization either because the same individual behavior has different consequences when displayed in a larger group or because larger groups are subject to different constraints and selection pressures than smaller groups. In eusocial colonies, group size may have similar effects on colony traits as body size has on organismal traits. Social insects may, therefore, be useful to test theories about general principles of scaling, as they constitute a distinct level of organization. However, there is a surprising lack of data on group sizes in social insects and other group-living arthropods, and multiple confounding factors have to be controlled to detect effects of group size. If such rigorous studies are performed, group size may become as important to understanding collective organization as is body size in explaining behavior and life history of individual organisms. © 2012 by Annual Reviews. All rights reserved.
• Duong, N., & Dornhaus, A. (2012). Ventilation response thresholds do not change with age or self-reinforcement in workers of the bumble bee Bombus impatiens. Insectes Sociaux, 59(1), 25-32.
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  Abstract: The response threshold model is a potential mechanism for task allocation in social insects, and it assumes that workers vary in the levels of task stimuli to which they respond. Furthermore, response thresholds of individual workers may change over time through self-reinforcement (experience), such that workers become more sensitive to task stimuli. However, in addition to self-reinforcement, aging is another process that occurs through time. Distinguishing whether response thresholds change within workers due to self-reinforcement or aging may give insight into the flexibility of this task allocation mechanism. Using a ventilation paradigm, we manipulated workers of Bombus impatiens to have either repeated or lack of exposures to increases in nest air temperature, thereby allowing us to manipulate experience and thus self-reinforcement. Nest air temperature was the task stimulus, and ventilation (fanning) was the behavioral response. We found that ventilation response thresholds do not decrease either with age or experience in workers of B. impatiens, contrary to what has been reported for B. terrestris workers (Weidenmüller, 2004). Instead, we found high levels of intra-individual variation in response thresholds. Our results also show that workers with lower average response thresholds respond to heating events with higher probability than those with higher ventilation thresholds. These results provide insight into the role of the response threshold framework for task allocation; we also discuss how response probabilities may play a role in task allocation among workers. © 2011 International Union for the Study of Social Insects (IUSSI).
• Goldsby, H. J., Dornhaus, A., Kerr, B., & Ofria, C. (2012). Task-switching costs promote the evolution of division of labor and shifts in individuality. Proceedings of the National Academy of Sciences of the United States of America, 109(34), 13686-13691.
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  PMID: 22872867;PMCID: PMC3427090;Abstract: From microbes to humans, the success of many organisms is achieved by dividing tasks among specialized group members. The evolution of such division of labor strategies is an important aspect of the major transitions in evolution. As such, identifying specific evolutionary pressures that give rise to group-level division of labor has become a topic of major interest among biologists. To overcome the challenges associated with studying this topic in natural systems, we use actively evolving populations of digital organisms, which provide a unique perspective on the de novo evolution of division of labor in an open-ended system. We provide experimental results that address a fundamental question regarding these selective pressures: Does the ability to improve group efficiency through the reduction of task-switching costs promote the evolution of division of labor? Our results demonstrate that as task-switching costs rise, groups increasingly evolve division of labor strategies. We analyze the mechanisms by which organisms coordinate their roles and discover strategies with striking biological parallels, including communication, spatial patterning, and task-partitioning behaviors. In many cases, under high task-switching costs, individuals cease to be able to perform tasks in isolation, instead requiring the context of other group members. The simultaneous loss of functionality at a lower level and emergence of new functionality at a higher level indicates that task-switching costs may drive both the evolution of division of labor and also the loss of lower-level autonomy, which are both key components of major transitions in evolution.
• Jandt, J. M., Robins, N. S., Moore, R. E., & Dornhaus, A. (2012). Individual bumblebees vary in response to disturbance: A test of the defensive reserve hypothesis. Insectes Sociaux, 59(3), 313-321.
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  Abstract: Bees may leave their nest in the event of an attack, but this is not their only response. Here, we examine the behavior of those individuals that remain inside the nest during a disturbance. Specifically, we test the hypothesis that bee workers usually exhibiting high levels of inactivity (i.e., 'lazy' bees) may function as defensive reserves that are more likely to respond when the colony is disturbed. We explore this hypothesis by simulating vertebrate attacks by vibrating or blowing carbon dioxide into two colonies on alternating days and measuring the movements and tasks performed by bees inside the nest. Our results show that regardless of the disturbance type, workers increase guarding behavior after a disturbance stops. Although previously inactive bees increased their movement speed inside the nest when the disturbance was vibration, they were not more likely to leave the nest (presumably to attack the simulated attacker) or switch to guarding behavior for any disturbance type. We therefore reject the hypothesis that inactive Bombus impatiens bumblebees act as defensive reserves, and propose alternative hypotheses regarding why many workers remain inactive inside the nest. © International Union for the Study of Social Insects (IUSSI) 2012.
• Kaczorowski, R. L., Leonard, A. S., Dornhaus, A., & Papaj, D. R. (2012). Floral signal complexity as a possible adaptation to environmental variability: A test using nectar-foraging bumblebees, Bombus impatiens. ANIMAL BEHAVIOUR, 83(4), 905-913.
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  Abstract: Floral signals are typically emitted across multiple sensory modalities, although why they are multimodal is unclear. One possible explanation is that multimodal signalling ensures that at least one signal component will be transmitted effectively under varying environmental conditions (the 'efficacy backup' hypothesis). For example, by transmitting both component A and B, a signaller can communicate under environmental conditions where transmission of component A is reduced; component B 'backs up' A. To test this hypothesis, we determined whether a floral scent could back up a floral colour signal when light levels were low. We trained nectar-foraging bumblebees to discriminate rewarding and unrewarding targets that differed in colour, scent, or both colour and scent, and then presented the targets at different levels of illumination. We measured bees' accuracy at distinguishing the two targets and their rate of visits to the trained target. Performance on both measures declined under low light when targets were unscented. The presence of scent reduced the loss of accuracy under low light, supporting the efficacy backup hypothesis, but this effect depended upon the colour of the previously rewarded target. In contrast, the presence of scent did not affect the overall rate of correct visits under low light (correct visits/foraging time). A backup mechanism that maintains accuracy, but not rate of nectar collection, does not necessarily benefit the pollinator. However, it most likely benefits the plant through reduced pollen wastage. In short, multimodal floral signals may benefit the plant by improving pollen transfer, while not benefiting the pollinator. © 2012 The Association for the Study of Animal Behaviour.
• Kaczorowski, R. L., Leonard, A. S., Dornhaus, A., & Papaj, D. R. (2012). Floral signal complexity as a possible adaptation to environmental variability: A test using nectar-foraging bumblebees, Bombus impatiens. Animal Behaviour, 83(4), 905-913.
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  Abstract: Floral signals are typically emitted across multiple sensory modalities, although why they are multimodal is unclear. One possible explanation is that multimodal signalling ensures that at least one signal component will be transmitted effectively under varying environmental conditions (the 'efficacy backup' hypothesis). For example, by transmitting both component A and B, a signaller can communicate under environmental conditions where transmission of component A is reduced; component B 'backs up' A. To test this hypothesis, we determined whether a floral scent could back up a floral colour signal when light levels were low. We trained nectar-foraging bumblebees to discriminate rewarding and unrewarding targets that differed in colour, scent, or both colour and scent, and then presented the targets at different levels of illumination. We measured bees' accuracy at distinguishing the two targets and their rate of visits to the trained target. Performance on both measures declined under low light when targets were unscented. The presence of scent reduced the loss of accuracy under low light, supporting the efficacy backup hypothesis, but this effect depended upon the colour of the previously rewarded target. In contrast, the presence of scent did not affect the overall rate of correct visits under low light (correct visits/foraging time). A backup mechanism that maintains accuracy, but not rate of nectar collection, does not necessarily benefit the pollinator. However, it most likely benefits the plant through reduced pollen wastage. In short, multimodal floral signals may benefit the plant by improving pollen transfer, while not benefiting the pollinator. © 2012 The Association for the Study of Animal Behaviour.
• Kulahci, I. G., Dornhaus, A., & Papaj, D. R. (2012). Multimodal signals enhance decision making in foraging bumble-bees. PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES, 275(1636), 797-802.
• Pinter-Wollman, N., Hubler, J., Holley, J., Franks, N. R., & Dornhaus, A. (2012). How is activity distributed among and within tasks in Temnothorax ants?. Behavioral Ecology and Sociobiology, 66(10), 1407-1420.
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  Abstract: How social insect colonies behave results from the actions of their workers. Individual variation among workers in their response to various tasks is necessary for the division of labor within colonies. A worker may be active in only a subset of tasks (specialist), perform all tasks (elite), or exhibit no particular pattern of task activity (idiosyncratic). Here we examine how worker activity is distributed among and within tasks in ants of the genus Temnothorax. We found that workers exhibited elitism within a situation, i. e., in particular sets of tasks, such as those associated with emigrations, nest building, or foraging. However, there was weak specialization for working in a particular situation. A few workers exhibited elitism across all situations, i. e., high performance in all tasks in all situations. Within any particular task, the distribution of activity among workers was skewed, with few ants performing most of the work and most ants performing very little of the work. We further found that workers persisted in their task preference over days, with the same individuals performing most of the work day after day. Interestingly, colonies were robust to the removal of these highly active workers; they were replaced by other individuals that were previously less active. This replacement was not short-lived; when the removed individuals were returned to the colony, not all of them resumed their prior high activity levels, and not all the workers that replaced them reduced their activity. Thus, even though some workers specialize in tasks within a particular situation and are persistent in performing them, task allocation in a colony is plastic and colonies can withstand removal of highly active individuals. © 2012 Springer-Verlag.
• Bengston, S. E., & Dornhaus, A. (2014). Be meek or be bold? A colony-level behavioural syndrome in ants. Proceedings of the Royal Society B: Biological Sciences, 281(1791), 20140518.
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  Consistent individual variation in animal behaviour is nearly ubiquitous and has important ecological and evolutionary implications. Additionally, suites of behavioural traits are often correlated, forming behavioural syndromes in both humans and other species. Such syndromes are often described by testing for variation in traits across commonly described dimensions (e. g. aggression and neophobia), independent of whether this variation is ecologically relevant to the focal species. Here, we use a variety of ecologically relevant behavioural traits to test for a colony-level behavioural syndrome in rock ants (Temnothorax rugatulus). Specifically, we combine field and laboratory assays to measure foraging effort, how colonies respond to different types of resources, activity level, response to threat and aggression level. We find evidence for a colony level syndrome that suggests colonies consistently differ in coping style-some are more risk-prone, whereas others are more risk-averse. Additionally, by collecting data across the North American range of this species, we show that environmental variation may affect how different populations maintain consistent variation in colony behaviour.
• Bengston, S. E., Jandt, J. M., Dornhaus, A., & Bengston, S. E. (2011). Food Exploitation by Social Insects: Ecological, Behavioral, and Theoretical Approaches. Contemporary Topics in Entomology Series. Edited by Stefan Jarau and Michael Hrncir. CRC Press. Boca Raton (Florida): Taylor & Francis. $119.95. xii + 348 p. + 4 pl.; ill.; index. ISBN: 978-1-4200-7560-1. 2009.. The Quarterly Review of Biology, 86(4), 359-359. doi:10.1086/662482
• Blonder, B., & Dornhaus, A. (2011). Time-ordered networks reveal limitations to information flow in ant colonies. PLoS ONE, 6(5).
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  PMID: 21625450;PMCID: PMC3098866;Abstract: Background: An important function of many complex networks is to inhibit or promote the transmission of disease, resources, or information between individuals. However, little is known about how the temporal dynamics of individual-level interactions affect these networks and constrain their function. Ant colonies are a model comparative system for understanding general principles linking individual-level interactions to network-level functions because interactions among individuals enable integration of multiple sources of information to collectively make decisions, and allocate tasks and resources. Methodology/Findings: Here we show how the temporal and spatial dynamics of such individual interactions provide upper bounds to rates of colony-level information flow in the ant Temnothorax rugatulus. We develop a general framework for analyzing dynamic networks and a mathematical model that predicts how information flow scales with individual mobility and group size. Conclusions/Significance: Using thousands of time-stamped interactions between uniquely marked ants in four colonies of a range of sizes, we demonstrate that observed maximum rates of information flow are always slower than predicted, and are constrained by regulation of individual mobility and contact rate. By accounting for the ordering and timing of interactions, we can resolve important difficulties with network sampling frequency and duration, enabling a broader understanding of interaction network functioning across systems and scales. © 2011 Blonder, Dornhaus.
• Charbonneau, D., Hillis, N., & Dornhaus, A. (2015). 'Lazy' in nature: ant colony time budgets show high 'inactivity' in the field as well as in the lab. Insectes sociaux, 62, 31-35.
• Couvillon, M. J., Jandt, J. M., Bonds, J., Helm, B., & Dornhaus, A. (2011). Percent lipid is associated with body size but not task in the bumble bee Bombus impatiens. Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology, 197(11), 1097-1104.
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  PMID: 21847618;Abstract: In some group-living organisms, labor is divided among individuals. This allocation to particular tasks is frequently stable and predicted by individual physiology. Social insects are excellent model organisms in which to investigate the interplay between physiology and individual behavior, as division of labor is an important feature within colonies, and individual physiology varies among the highly related individuals of the colony. Previous studies have investigated what factors are important in determining how likely an individual is, compared to nestmates, to perform certain tasks. One such task is foraging. Corpulence (i. e., percent lipid) has been shown to determine foraging propensity in honey bees and ants, with leaner individuals being more likely to be foragers. Is this a general trend across all social insects? Here we report data analyzing the individual physiology, specifically the percent lipid, of worker bumble bees (Bombus impatiens) from whom we also analyze behavioral task data. Bumble bees are also unusual among the social bees in that workers may vary widely in size. Surprisingly we find that, unlike other social insects, percent lipid is not associated with task propensity. Rather, body size closely predicts individual relative lipid stores, with smaller worker bees being allometrically fatter than larger worker bees. © 2011 Springer-Verlag.
• Fletcher, M., Dornhaus, A., & Shin, M. C. (2011). Multiple ant tracking with global foreground maximization and variable target proposal distribution. 2011 IEEE Workshop on Applications of Computer Vision, WACV 2011, 570-576.
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  Abstract: Motion and behavior analysis of social insects such as ants requires tracking many ants over time. This process is highly labor-intensive and tedious. Automatic tracking is challenging as ants often interact with one another, resulting in frequent occlusions that cause drifts in tracking. In addition, tracking many objects is computationally expensive. In this paper, we present a robust and efficient method for tracking multiple ants. We first prevent drifts by maximizing the coverage of foreground pixels at at global scale. Secondly, we improve speed by reducing markov chain length through dynamically changing the target proposal distribution for perturbed ant selection. Using a real dataset with ground truth, we demonstrate that our algorithm was able to improve the accuracy by 15% (resulting in 98% tracking accuracy) and the speed by 76%. © 2010 IEEE.
• Jandt, J. M., & Dornhaus, A. (2011). Competition and cooperation: Bumblebee spatial organization and division of labor may affect worker reproduction late in life. Behavioral Ecology and Sociobiology, 65(12), 2341-2349.
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  Abstract: Within-group conflict may influence the degree to which individuals within a group cooperate. For example, the most dominant individuals within a group often gain access to the best resources and may be less inclined to perform risky tasks. We monitored space use and division of labor among all workers in three colonies of bumblebees, Bombus impatiens, during the ergonomic and queenless phases of their colony cycle. We then measured the two largest oocytes in each worker to estimate each individual's reproductive potential at the end of the colony cycle. We show that workers that remained farther from the queen while inside the nest and avoided risky or more energy-expensive tasks during the ergonomic phase developed larger oocytes by the end of the colony cycle. These individuals also tended to be the largest, oldest workers. After the queen died, these workers were more likely than their nestmates to increase brood incubation. Our results suggest that inactive bumblebees may be storing fat reserves to later develop reproductive organs and that the spatial organization of workers inside the nest, particularly the distance workers maintain from the queen, may predict which individuals will later have the greatest reproductive potential in the colony. © 2011 Springer-Verlag.
• Jandt, J. M., & Dornhaus, A. (2014). Bumblebee response thresholds and body size: does worker diversity increase colony performance?. Animal Behaviour, 87, 97-106.
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  Abstract: Although models of colony organization in social insects often rely on the assumption that within-group variation increases group performance, empirical support for this is mostly confined to studies of genetic variation. However, workers in ant or bee colonies often vary in behaviour and morphology even when genetic variation is low. Bumblebees provide a unique opportunity to explore the consequences of such variation: colonies have a wide range of worker body sizes compared to other social bee species, and workers also vary in response thresholds (i.e. stimulus levels at which workers respond by performing a task), in spite of queens being singly mated (and thus, low genetic variation). Here we test how body size and response threshold diversity affect colony performance in two unrelated in-nest tasks (thermoregulation and undertaking). We manipulated worker diversity using worker removals to restrict threshold or body size variation within the colony. We also quantified the degree of intracolony variation across colonies and related this to colony performance. In general, colonies took longer to cool the nest after bees were removed, but there was no significant effect of treatment on fanning or undertaking success. Furthermore, when intracolony variation was analysed as a continuous variable, we found no effect on colony-level thermoregulation or undertaking performance. Instead, average threshold was a more useful predictor of thermoregulation success, and colonies with a narrower range of size variation had more success at undertaking. These results emphasize the importance of understanding how different types of variation (e.g. behavioural, morphological, etc.) contribute to colony performance. © 2013 The Association for the Study of Animal Behaviour.
• Jones, E. I., & Dornhaus, A. (2011). Predation risk makes bees reject rewarding flowers and reduce foraging activity. Behavioral Ecology and Sociobiology, 65(8), 1505-1511.
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  Abstract: In the absence of predators, pollinators can often maximize their foraging success by visiting the most rewarding flowers. However, if predators use those highly rewarding flowers to locate their prey, pollinators may benefit from changing their foraging preferences to accept less rewarding flowers. Previous studies have shown that some predators, such as crab spiders, indeed hunt preferentially on the most pollinator-attractive flowers. In order to determine whether predation risk can alter pollinator preferences, we conducted laboratory experiments on the foraging behavior of bumble bees (Bombus impatiens) when predation risk was associated with a particular reward level (measured here as sugar concentration). Bees foraged in arenas containing a choice of a high-reward and a low-reward artificial flower. On a bee's first foraging trip, it was either lightly squeezed with forceps, to simulate a crab spider attack, or was allowed to forage safely. The foragers' subsequent visits were recorded for between 1 and 4 h without any further simulated attacks. Compared to bees that foraged safely, bees that experienced a simulated attack on a low-reward artificial flower had reduced foraging activity. However, bees attacked on a high-reward artificial flower were more likely to visit low-reward artificial flowers on subsequent foraging trips. Forager body size, which is thought to affect vulnerability to capture by predators, did not have an effect on response to an attack. Predation risk can thus alter pollinator foraging behavior in ways that influence the number and reward level of flowers that are visited. © 2011 Springer-Verlag.
• Lanan, M. C., Dornhaus, A., & Bronstein, J. L. (2011). The function of polydomy: the ant Crematogaster torosa preferentially forms new nests near food sources and fortifies outstations. BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY, 65(5), 959-968.
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  Many ant species are polydomous, forming multiple spatially segregated nests that exchange workers and brood. However, why polydomy occurs is still uncertain. We investigated whether colonies of Crematogaster torosa form new polydomous nests to better exploit temporally stable food resources. Specifically, we tested the effect of food presence or absence and distance on the likelihood that colonies would form a new nest. Because this species also forms little-known structures that house only workers without brood (outstations), we also compared the function of this structure with true nests. Laboratory-reared colonies were connected to a new foraging arena containing potential nest sites with or without food for 4 months. When food was present, most colonies formed polydomous nests nearby and the remainder formed outstations. When food was absent, the behavior of colonies differed significantly, frequently forming outstations but never polydomous nests. Distance had no effect on the type of structure formed, but when food was present, a larger proportion of the workforce moved shorter distances. Workers often fortified the entrances to both structures and used them for storage of dried insect tissue ("jerky"). In an investigation of spatial fidelity, we found that workers on the between-nest trail were associated with the original nest, whereas workers collecting food were more likely to be associated with the new nest or outstation. C. torosa appears to have a flexible colony structure, forming both outstations and polydomous nests. Polydomous nests in this species were associated with foraging and were only formed near food resources.
• Lanan, M. C., Dornhaus, A., Jones, E. I., Waser, A., & Bronstein, J. L. (2012). The Trail Less Traveled: Individual Decision-Making and Its Effect on Group Behavior. PLOS ONE, 7(10), e47976.
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  Social insect colonies are complex systems in which the interactions of many individuals lead to colony-level collective behaviors such as foraging. However, the emergent properties of collective behaviors may not necessarily be adaptive. Here, we examine symmetry breaking, an emergent pattern exhibited by some social insects that can lead colonies to focus their foraging effort on only one of several available food patches. Symmetry breaking has been reported to occur in several ant species. However, it is not clear whether it arises as an unavoidable epiphenomenon of pheromone recruitment, or whether it is an adaptive behavior that can be controlled through modification of the individual behavior of workers. In this paper, we used a simulation model to test how symmetry breaking is affected by the degree of non-linearity of recruitment, the specific mechanism used by individuals to choose between patches, patch size, and forager number. The model shows that foraging intensity on different trails becomes increasingly asymmetric as the recruitment response of individuals varies from linear to highly non-linear, supporting the predictions of previous work. Surprisingly, we also found that the direction of the relationship between forager number (i.e., colony size) and asymmetry varied depending on the specific details of the decision rule used by individuals. Limiting the size of the resource produced a damping effect on asymmetry, but only at high forager numbers. Variation in the rule used by individual ants to choose trails is a likely mechanism that could cause variation among the foraging behaviors of species, and is a behavior upon which selection could act.
• Leonard, A. S., Dornhaus, A., & Papaj, D. R. (2011). Flowers help bees cope with uncertainty: signal detection and the function of floral complexity. Journal of Experimental Biology, 214, 113-121.
• Leonard, A. S., Dornhaus, A., & Papaj, D. R. (2011). Forget-me-not: Complex floral displays, inter-signal interactions, and pollinator cognition. CURRENT ZOOLOGY, 57(2), 215-224.
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  Abstract: Flowers are multisensory displays used by plants to influence the behavior of pollinators. Although we know a great deal about how individual signal components are produced by plants and detected or learned by pollinators, very few experiments directly address the function of floral signal complexity, i.e. how the multicomponent nature of these signals benefits plant or pollinator. Yet, experimental psychology suggests that increasing complexity can enhance subjects' ability to detect, learn and remember stimuli, and the plant's reproductive success depends upon ensuring that pollinators learn their signals and so transport pollen to other similar (conspecific) flowers. Here we explore functional hypotheses for why plants invest in complex floral displays, focusing on hypotheses in which floral signals interact to promote pollinator learning and memory. Specifically, we discuss how an attention-altering or context-providing function of one signal may promote acquisition or recall of a second signal. Although we focus on communication between plants and pollinators, these process-based hypotheses should apply to any situation where a sender benefits from enhancing a receiver's acquisition or recall of information. © 2011 Current Zoology.
• Leonard, A. S., Dornhaus, A., & Papaj, D. R. (2011). Forget-me-not: Complex floral displays, inter-signal interactions, and pollinator cognition. Current Zoology, 57(2), 215-224.
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  Abstract: Flowers are multisensory displays used by plants to influence the behavior of pollinators. Although we know a great deal about how individual signal components are produced by plants and detected or learned by pollinators, very few experiments directly address the function of floral signal complexity, i.e. how the multicomponent nature of these signals benefits plant or pollinator. Yet, experimental psychology suggests that increasing complexity can enhance subjects' ability to detect, learn and remember stimuli, and the plant's reproductive success depends upon ensuring that pollinators learn their signals and so transport pollen to other similar (conspecific) flowers. Here we explore functional hypotheses for why plants invest in complex floral displays, focusing on hypotheses in which floral signals interact to promote pollinator learning and memory. Specifically, we discuss how an attention-altering or context-providing function of one signal may promote acquisition or recall of a second signal. Although we focus on communication between plants and pollinators, these process-based hypotheses should apply to any situation where a sender benefits from enhancing a receiver's acquisition or recall of information. © 2011 Current Zoology.
• Leonard, A. S., Dornhaus, A., Papaj, D. R., Leonard, A. S., Dornhaus, A., Papaj, D. R., Leonard, A. S., Dornhaus, A., & Papaj, D. R. (2011). Flowers help bees cope with uncertainty: signal detection and the function of floral complexity. THE JOURNAL OF EXPERIMENTAL BIOLOGY, 214, 113-121.
• Muth, F., Keasar, T., & Dornhaus, A. (2015). Trading off short-term costs for long-term gains: how do bumblebees decide to learn morphologically complex flowers?. Animal Behaviour, 101, 191-199.
• Couvillon, M. J., & Dornhaus, A. (2010). Small worker bumble bees (Bombus impatiens) are hardier against starvation than their larger sisters. Insectes Sociaux, 57(2), 193-197.
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  Abstract: In bumble bees (Bombus spp.), where workers within the same colony exhibit up to a tenfold difference in mass, labor is divided by body size. Current adaptive explanations for this important life history feature are unsatisfactory. Within the colony, what is the function of the smaller workers? Here, we report on the differential robustness to starvation of small and large worker bumble bees (Bombus impatiens); when nectar is scarce, small workers remain alive significantly longer than larger workers. The presence of small workers, and size variation in general, might act as insurance against times of nectar shortage. These data may provide a novel, adaptive explanation, independent of division of labor, for size polymorphism within the worker caste. © Birkhäuser Verlag, Basel/Switzerland 2009.
• Couvillon, M. J., Fitzpatrick, G., & Dornhaus, A. (2010). Ambient air temperature does not predict whether small or large workers forage in bumble bees (Bombus impatiens). Psyche.
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  Abstract: Bumble bees are important pollinators of crops and other plants. However, many aspects of their basic biology remain relatively unexplored. For example, one important and unusual natural history feature in bumble bees is the massive size variation seen between workers of the same nest. This size polymorphism may be an adaptation for division of labor, colony economics, or be nonadaptive. It was also suggested that perhaps this variation allows for niche specialization in workers foraging at different temperatures: larger bees might be better suited to forage at cooler temperatures and smaller bees might be better suited to forage at warmer temperatures. This we tested here using a large, enclosed growth chamber, where we were able to regulate the ambient temperature. We found no significant effect of ambient or nest temperature on the average size of bees flying to and foraging from a suspended feeder. Instead, bees of all sizes successfully flew and foraged between 16 °C and 36 °C. Thus, large bees foraged even at very hot temperatures, which we thought might cause overheating. Size variation therefore could not be explained in terms of niche specialization for foragers at different temperatures. © 2010 Margaret J. Couvillon et al.
• Couvillon, M. J., Jandt, J. M., Duong, N., & Dornhaus, A. (2010). Ontogeny of worker body size distribution in bumble bee (Bombus impatiens) colonies. Ecological Entomology, 35(4), 424-435.
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  Abstract: 1. Bumble bees exhibit worker size polymorphisms; highly related workers within a colony may vary up to 10-fold in body mass. As size variation is an important life history feature in bumble bees, the distribution of body sizes within the colony and how it fluctuates over the colony cycle were analysed. 2. Ten commercially purchased colonies of Bombus impatiens (Cresson) were reared in ad libitum conditions. The size of all workers present and newly emerging workers (callows) was recorded each week. 3. The average size of bumble bee workers did not change with colony age, but variation in body size tended to decrease over time. The average size of callows did not change with population size, but did tend to decrease with colony age. In all measures, there was considerable variation among colonies. 4. Colonies of B. impatiens usually produced workers with normally distributed body sizes throughout the colony life cycle. Unlike most polymorphic ants, there was no increase in worker body size with colony age or colony size. This provides the first, quantitative data on the ontogeny of bumble bee worker size distribution. The potential adaptive significance of this size variation is discussed. © 2010 The Authors. Journal compilation © 2010 The Royal Entomological Society.
• Ferguson, H. M., Dornhaus, A., Beeche, A., Borgemeister, C., Gottlieb, M., Mulla, M. S., Gimnig, J. E., Fish, D., & Killeen, G. F. (2010). Ecology: A prerequisite for malaria elimination and eradication. PLoS Medicine, 7(8), e1000303.
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  PMID: 20689800;PMCID: PMC2914634;Abstract: Existing front-line vector control measures, such as insecticide-treated nets and residual sprays, cannot break the transmission cycle of Plasmodium falciparum in the most intensely endemic parts of Africa and the Pacific. The goal of malaria eradication will require urgent strategic investment into understanding the ecology and evolution of the mosquito vectors that transmit malaria. Priority areas will include understanding aspects of the mosquito life cycle beyond the blood feeding processes which directly mediate malaria transmission. Global commitment to malaria eradication necessitates a corresponding longterm commitment to vector ecology.
• A., J., Bogacz, R., Dornhaus, A., Planqué, R., Kovacs, T., & Franks, N. R. (2009). On optimal decision-making in brains and social insect colonies. Journal of the Royal Society Interface, 6(40), 1065-1074.
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  PMID: 19324679;PMCID: PMC2827444;Abstract: The problem of how to compromise between speed and accuracy in decision-making faces organisms at many levels of biological complexity. Striking parallels are evident between decision-making in primate brains and collective decision-making in social insect colonies: in both systems, separate populations accumulate evidence for alternative choices; when one population reaches a threshold, a decision is made for the corresponding alternative, and this threshold may be varied to compromise between the speed and the accuracy of decision-making. In primate decision-making, simple models of these processes have been shown, under certain parametrizations, to implement the statistically optimal procedure that minimizes decision time for any given error rate. In this paper, we adapt these same analysis techniques and apply them to new models of collective decision-making in social insect colonies. We show that social insect colonies may also be able to achieve statistically optimal collective decision-making in a very similar way to primate brains, via direct competition between evidence-accumulating populations. This optimality result makes testable predictions for how collective decision-making in social insects should be organized. Our approach also represents the first attempt to identify a common theoretical framework for the study of decision-making in diverse biological systems. © 2009 The Royal Society.
• Couvillon, M. J., & Dornhaus, A. (2009). Location, location, location: larvae position inside the nest is correlated with adult body size in worker bumble-bees (Bombus impatiens). Proceedings. Biological sciences / The Royal Society, 276(1666), 2411-2418.
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  Social insects display task-related division of labour. In some species, division of labour is related to differences in body size, and worker caste members display morphological adaptations suited for particular tasks. Bumble-bee workers (Bombus spp.) can vary in mass by eight- to tenfold within a single colony, which previous work has linked to division of labour. However, little is known about the proximate mechanism behind the production of this wide range of size variation within the worker caste. Here, we quantify the larval feeding in Bombus impatiens in different nest zones of increasing distance from the centre. There was a significant difference in the number of feedings per larva across zones, with a significant decrease in feeding rates as one moved outwards from the centre of the nest. Likewise, the diameter of the pupae in the peripheral zones was significantly smaller than that of pupae in the centre. Therefore, we conclude that the differential feeding of larvae within a nest, which leads to the size variation within the worker caste, is based on the location of brood clumps. Our work is consistent with the hypothesis that some larvae are 'forgotten', providing a possible first mechanism for the creation of size polymorphism in B. impatiens.
• Dornhaus, A., Holley, J., & Franks, N. R. (2009). Larger colonies do not have more specialized workers in the ant Temnothorax albipennis. Behavioral Ecology, 20(5), 922-929.
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  Abstract: Social insects are distinguished by their extraordinary degree of cooperation and the complexity of their group organization. However, a high proportion of individuals (often >50% at any one time) in a social insect colony tend to be inactive. It has been hypothesized that larger colonies can afford such inactivity because of efficiencies gained through stronger division of labor. We quantify the degree to which colonies of different sizes exhibit division of labor, and what proportion tends to be inactive, in the ant Temnothorax albipennis. Colony size neither influenced individual specialization nor overall division of labor in this species and larger colonies did not show a higher proportion of inactive workers. Interestingly, small colonies seemed to rely more on a small number of high-performance workers: the proportion of work performed by the single most active worker is significantly higher in smaller colonies for several tasks. More research is needed to resolve when and how colony size affects collective organization and division of labor in insect colonies.
• Jandt, J. M., & Dornhaus, A. (2009). Spatial organization and division of labour in the bumble bee Bombus impatiens. Animal Behaviour, 77(3), 641-651.
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  Abstract: Individuals in many types of animal groups show both reproductive and task-related division of labour. In some social insect species, such division of labour may be related to the spatial organization of workers inside the nest. We examined colonies of bumblebees and found that (1) 11-13% of workers maintained small spatial fidelity zones inside the nest, and all workers tended to remain at a specific distance from the colony centre independent of their age; (2) smaller individuals maintained smaller spatial zones and tended to be closer to the centre; and (3) individuals that were more likely to perform the in-nest task of larval feeding tended to remain in the centre of the nest, whereas foragers were more often found on the periphery of the nest when not foraging. Individuals that performed other tasks did not maintain a predictable distance to the centre, and there was no evidence that spatial preferences changed over time. Instead, spatial patterns may result from inherent differences between individuals in terms of activity level, and may be a self-organized sorting mechanism that influences division of labour among workers.
• Jandt, J. M., Huang, E., & Dornhaus, A. (2009). Weak specialization of workers inside a bumble bee (Bombus impatiens) nest. Behavioral Ecology and Sociobiology, 63(12), 1829-1836.
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  Abstract: Division of labor is common across social groups. In social insects, many studies focus on the differentiation of in-nest and foraging workers and/or the division of foraging tasks. Few studies have specifically examined how workers divide in-nest tasks. In the bumble bee, Bombus impatiens, we have shown previously that smaller workers are more likely to feed larvae and incubate brood, whereas larger workers are more likely to fan or guard the nest. Here, we show that in spite of this, B. impatiens workers generally perform multiple tasks throughout their life. The size of this task repertoire size does not depend on body size, nor does it change with age. Further, individuals were more likely to perform the task they had been performing on the previous day than any other task, a pattern most pronounced among individuals who guarded the nest. On the other hand, there was no predictable sequence of task switching. Because workers tend to remain in the same region of the nest over time, in-nest workers may concentrate on a particular task, or subset of tasks, inside that region. This division of space, then, may be an important mechanism that leads to this weak specialization among in-nest bumble bee workers. © 2009 Springer-Verlag.
• Dornhaus, A. (2008). Specialization does not predict individual efficiency in an ant. PLoS Biology, 6(11), 2368-2375.
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  PMID: 19018663;Abstract: The ecological success of social insects is often attributed to an increase in efficiency achieved through division of labor between workers in a colony. Much research has therefore focused on the mechanism by which a division of labor is implemented, i.e., on how tasks are allocated to workers. However, the important assumption that specialists are indeed more efficient at their work than generalist individuals - the "Jack-of-all-trades is master of none" hypothesis - has rarely been tested. Here, I quantify worker efficiency, measured as work completed per time, in four different tasks in the ant Temnothorax albipennis: honey and protein foraging, collection of nest-building material, and brood transports in a colony emigration. I show that individual efficiency is not predicted by how specialized workers were on the respective task. Worker efficiency is also not consistently predicted by that worker's overall activity or delay to begin the task. Even when only the worker's rank relative to nestmates in the same colony was used, specialization did not predict efficiency in three out of the four tasks, and more specialized workers actually performed worse than others in the fourth task (collection of sand grains). I also show that the above relationships, as well as median individual efficiency, do not change with colony size. My results demonstrate that in an ant species without morphologically differentiated worker castes, workers may nevertheless differ in their ability to perform different tasks. Surprisingly, this variation is not utilized by the colony - worker allocation to tasks is unrelated to their ability to perform them. What, then, are the adaptive benefits of behavioral specialization, and why do workers choose tasks without regard for whether they can perform them well? We are still far from an understanding of the adaptive benefits of division of labor in social insects. © 2008 Anna Dornhaus.
• Dornhaus, A., & Cao, T. T. (2008). Ants under crowded conditions consume more energy. Biology Letters, 4(6), 613-615. doi:10.1098/rsbl.2008.0381
• Dornhaus, A., & Franks, N. R. (2008). Individual and collective cognition in ants and other insects (Hymenoptera: Formicidae). Myrmecological News, 11, 215-226.
• Dornhaus, A., Cao, T. T., & Dornhaus, A. R. (2008). Ants under crowded conditions consume more energy. Biology letters, 4(6).
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  Social insects live in colonies consisting of many workers, where worker interactions play an important role in regulating colony activities. Workers interact within the social space of the nest; therefore, constraints on nest space may alter worker behaviour and affect colony activities and energetics. Here we show in the ant Temnothorax rugatulus that changes in nest space have a significant effect on colony energetics. Colonies with restricted nest space showed a 14.2 per cent increase in metabolic rate when compared with the same colonies in large uncrowded nests. Our study highlights the importance of social space and shows that constraints on social space can significantly affect colony behaviour and energy use in ants. We discuss the implications of our findings regarding social insects in general.
• Dornhaus, A., Holley, J., Pook, V. G., Worswick, G., & Franks, N. R. (2008). Why do not all workers work? Colony size and workload during emigrations in the ant Temnothorax albipennis. Behavioral Ecology and Sociobiology, 63(1), 43-51.
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  Abstract: Here, we study distribution of workload and its relationship to colony size among worker ants of Temnothorax albipennis, in the context of colony emigrations. We find that one major aspect of workload, number of items transported by each worker, was more evenly distributed in larger colonies. By contrast, in small colonies, a small number of individuals perform most of the work in this task (in one colony, a single ant transported 57% of all items moved in the emigration). Transporters in small colonies carried more items to the new nest per individual and achieved a higher overall efficiency in transport (more items moved per transporter and unit time). Our results suggest that small colonies may be extremely dependent on a few key individuals. In studying colony organisation and division of labour, the amount of work performed by each individual, not just task repertoire (which tasks are performed at all), should be taken into account. © 2008 Springer-Verlag.
• Duong, N., & Dornhaus, A. (2008). Ventilation response thresholds do not change with age or self-reinforcement in workers of the bumble bee Bombus impatiens. INSECTES SOCIAUX, 59(1), 25-32.
• Huang, M. H., & Dornhaus, A. (2008). A meta-analysis of ant social parasitism: Host characteristics of different parasitism types and a test of Emery's rule. Ecological Entomology, 33(5), 589-596.
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  Abstract: 1. In ant social parasitism, the process by which parasite-host systems evolved and the types of invasion mechanisms parasites use are being debated. Emery's rule, for example, states that social parasites are the closest relatives to their hosts. The present study uses previously published data to test whether Emery's rule applies equally to all parasitism types (i.e. xenobiosis, temporary, dulosis, and inquilinism). In addition, this study also investigates other links between parasite-host relatedness and host biology, which has implications for understanding the invasion mechanisms used by certain parasites. 2. We find that xenobiotic parasites typically use distantly-related host species that are of at least medium colony size. Temporary parasites often have multiple host species that are very closely related to the parasite and hosts with medium-size colonies. Dulotic parasites frequently have multiple host species that are slightly less related and of any size. Lastly, inquiline parasites tend to have a single, very closely related, host species with medium-size colonies. 3. Parasites tend to be more closely related to host species if they have a single host species or when the host has a large colony size. In contrast, parasites with multiple host species or hosts of small colony size tend to be less related to their hosts. 4. This study is the first to examine trends in ant social parasitism across all known parasite species. Our meta-analysis shows that Emery's rule applies to inquilinism and temporary parasitism, but not to dulosis and xenobiosis. Our results also suggest that both parasitism type and parasite-host relatedness predict the number of hosts and host colony size. It may be that a chemical mimicry mechanism allows invasion of large host colonies, but requires close relatedness of parasite and host, and concentration on a single host species. © 2008 The Authors.
• Kulahci, I. G., Dornhaus, A., & Papaj, D. R. (2008). Multimodal signals enhance decision-making in foraging bumble-bees. Proceedings of the Royal Society B: Biological Sciences, 275, 797-802.
• Franks, N. R., Dornhaus, A., Hitchcock, G., Guillem, R., Hooper, J., & Webb, C. (2007). Avoidance of conspecific colonies during nest choice by ants. Animal Behaviour, 73(3), 525-534.
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  Abstract: Conspecific ant colonies are often overdispersed, i.e. they are further apart than they would be if they were distributed randomly. This overdispersion might be driven by competition for food resources or nest sites and may result from established colonies preventing incipient colonies from settling too close to them. We investigated another possible mechanism for overdispersion: active nest choice by emigrating colonies. Colonies may be influenced by the presence of conspecifics when they are emigrating from a nest that has become uninhabitable. In the laboratory, we presented Temnothorax albipennis ant colonies with a choice of three new nests, which were equidistant from their old nest site. The new nests were identical except that one was near to an established conspecific colony. The emigrating colonies significantly preferred the new nest site that was furthest from the resident colony. This selection was not just the result of access to the other nests being blocked by aggression from the resident colony; emigrating colonies thus made active choices. Odour cues may influence nest selection: odours left around nest sites by foreign colonies deterred nest occupancy. There was more aggression near the resident colony, but this appeared to be caused by the greater density of resident ants there rather than those ants being more aggressive per capita. We also observed a relatively high proportion of fusions between colonies. Possible reasons for this are considered together with their implications. © 2007 The Association for the Study of Animal Behaviour.
• Franks, N. R., Hooper, J. W., Dornhaus, A., Aukett, P. J., Hayward, A. L., & Berghoff, S. M. (2007). Reconnaissance and latent learning in ants. Proceedings of the Royal Society B: Biological Sciences, 274(1617), 1505-1509.
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  PMID: 17426016;PMCID: PMC2176157;Abstract: We show that ants can reconnoitre their surroundings and in effect plan for the future. Temnothorax albipennis colonies use a sophisticated strategy to select a new nest when the need arises. Initially, we presented colonies with a new nest of lower quality than their current one that they could explore for one week without a need to emigrate. We then introduced a second identical low quality new nest and destroyed their old nest so that they had to emigrate. Colonies showed a highly significant preference for the (low quality) novel new nest over the identical but familiar one. In otherwise identical experiments, colonies showed no such discrimination when the choice was between a familiar and an unfamiliar high-quality nest. When, however, either all possible pheromone marks were removed, or landmarks were re-orientated, just before the emigration, the ants chose between identical low-quality new nests at random. These results demonstrate for the first time that ants are capable of assessing and retaining information about the quality of potential new nest sites, probably by using both pheromones and landmark cues, even though this information may only be of strategic value to the colony in the future. They seem capable, therefore, of latent learning and, more explicitly, learning what not to do. © 2007 The Royal Society.
• Franks, N. R., Hooper, J. W., Gumn, M., Bridger, T. H., Marshall, J. A., Gross, R., & Dornhaus, A. R. (2007). Moving targets: collective decisions and flexible choices in house-hunting ants. Swarm Intelligence, 1, 81-94.
• Planqué, R., Dornhaus, A., Franks, N. R., Kovacs, T., & A., J. (2007). Weighting waiting in collective decision-making. Behavioral Ecology and Sociobiology, 61(3), 347-356.
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  Abstract: Animals searching for food, mates, or a home often need to decide when to stop looking and choose the best option found so far. By re-analyzing experimental data from experiments by Mallon et al. (Behav Ecol Sociobiol 50:352-359, 2001), we demonstrate that house-hunting ant colonies are gradually more committed to new nests during the emigration. Early in house-hunting, individual ants were flexibly committed to new nest sites. However, when carrying to a new nest had started, ants hardly ever switched preference. Using a theoretical model based on experimental data, we test at which stage flexible commitment influences speed and accuracy most. We demonstrate that ant colonies have found a good compromise between impatience and procrastination. Early flexibility combined with later rigidity is identically effective as other strategies that include flexible commitment, but it is particularly good when emigration conditions are harsh. © 2006 Springer-Verlag.
• Thom, C., & Dornhaus, A. (2007). Preliminary report on the use of volatile compounds by foraging honey bees in the hive (Hymenoptera: Apidae: Apis). Entomologia Generalis, 29(2-4), 299-304.
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  Abstract: A honey bee colony (Apis mellifera Linnaeus) frequently adjusts its nectar foraging effort to changes in foraging conditions. It is possible that workers use a volatile substance, e.g. a pheromone, to quickly activate foragers in all regions of the hive. To test whether volatiles from a foraging colony can activate foragers of a non-foraging colony, two colonies, each restricted to a different greenhouse, were connected with a glass tube that allowed volatiles to drift between colonies. During the experiment, one colony was allowed to forage unscented sugar water. The scent of the foraging colony was fanned into the colony that did not have sugar water available, and the number of times that workers each left the hive and arrived at the empty feeder station was recorded. The number of visits of the empty feeder by foragers from the non-foraging colony tended to increase, while the number of times that bees left the hive did not seem to change. The result suggests an increase in foraging motivation of already active foragers. However, the results will have to be corroborated by further experiments. © 2007 E. Schweizerbart'sche Verlagsbuchhandlung.
• Dornhaus, A., & Franks, N. R. (2006). Colony size affects collective decision-making in the ant Temnothorax albipennis. Insectes Sociaux, 53(4), 420-427.
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  Abstract: Social insects are well-known for their ability to achieve robust collective behaviours even when individuals have limited information. It is often assumed that such behaviours rely on very large group sizes, but many insect colonies start out with only a few workers. Here we investigate the influence of colony size on collective decision-making in the house-hunting of the ant Temnothorax albipennis. In experiments where colony size was manipulated by splitting colonies, we show that worker number has an influence on the speed with which colonies discover new nest sites, but not on the time needed to make a decision (achieve a quorum threshold) or total emigration time. This occurred because split colonies adopted a lower quorum threshold, in fact they adopted the same threshold in proportion to their size as full-size colonies. This indicates that ants may be measuring relative quorum, i.e. population in the new nest relative to that of the old nest, rather than the absolute number. Experimentally reduced colonies also seemed to gain more from experience through repeated emigrations, as they could then reduce nest discovery times to those of larger colonies. In colonies of different sizes collected from the field, total emigration time was also not correlated with colony size. However, quorum threshold was not correlated with colony size, meaning that individuals in larger colonies adopted relatively lower quorum thresholds. Since this is a different result to that from size-manipulated colonies, it strongly suggests that the differences between natural small and large colonies were not caused by worker number alone. Individual ants may have adjusted their behaviour to their colony's size, or other factors may correlate with colony size in the field. Our study thus shows the importance of experimentally manipulating colony size if the effect of worker number on the emergence of collective behaviour is to be studied. © Birkhäuser Verlag, 2006.
• Dornhaus, A., Collins, E. J., Dechaume-Moncharmont, F., Houston, A. I., Franks, N. R., & McNamara, J. M. (2006). Paying for information: Partial loads in central place foragers. Behavioral Ecology and Sociobiology, 61(1), 151-161.
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  Abstract: Information about food sources can be crucial to the success of a foraging animal. We predict that this will influence foraging decisions by group-living foragers, which may sacrifice short-term foraging efficiency to collect information more frequently. This result emerges from a model of a central-place forager that can potentially receive information on newly available superior food sources at the central place. Such foragers are expected to return early from food sources, even with just partial loads, if information about the presence of sufficiently valuable food sources is likely to become available. Returning with an incomplete load implies that the forager is at that point not achieving the maximum possible food delivery rate. However, such partial loading can be more than compensated for by an earlier exploitation of a superior food source. Our model does not assume cooperative foraging and could thus be used to investigate this effect for any social central-place forager. We illustrate the approach using numerical calculations for honeybees and leafcutter ants, which do forage cooperatively. For these examples, however, our results indicate that reducing load confers minimal benefits in terms of receiving information. Moreover, the hypothesis that foragers reduce load to give information more quickly (rather than to receive it) fits empirical data from social insects better. Thus, we can conclude that in these two cases of social-insect foraging, efficient distribution of information by successful foragers may be more important than efficient collection of information by unsuccessful ones. © 2006 Springer-Verlag.
• Dornhaus, A., Klügl, F., Oechslein, C., Puppe, F., & Chittka, L. (2006). Benefits of recruitment in honey bees: Effects of ecology and colony size in an individual-based model. Behavioral Ecology, 17(3), 336-344.
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  Abstract: Why do some social insects have sophisticated recruitment systems, while other species do not communicate about food source locations at all? To answer this question, it is necessary to identify the social or ecological factors that make recruitment adaptive and thus likely to evolve. We developed an individual-based model of honey bee foraging to quantify the benefits of recruitment under different spatial distributions of nondepleting resource patches and with different colony sizes. Benefits of recruitment were strongly dependent on resource patch quality, density, and variability. Communication was especially beneficial if patches were poor, few, and variable. A sensitivity analysis of the model showed that under conditions of high resource density recruitment could even become detrimental, especially if foraging duration was short, tendency to scout was high, or recruits needed a long time to find communicated locations. Colony size, a factor often suspected to influence recruitment evolution, had no significant effect. These results may explain the recent experimental findings that in honey bees, benefits of waggle dance recruitment seem to vary seasonally and with habitat. They may also explain why some, but not other, species of social bees have evolved a strategy to communicate food locations to nest mates.
• Franks, N. R., Dornhaus, A., Best, C. S., & Jones, E. L. (2006). Decision making by small and large house-hunting ant colonies: one size fits all. Animal Behaviour, 72(3), 611-616.
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  Abstract: We conducted two experiments with Temnothorax albipennis ant colonies. In the first, we assessed their ability to select the best nest, in terms of entrance size, among an array of mediocre ones. Small and large ant colonies were equally adept at solving this best-of-N choice problem. However, large colonies were faster than small ones at finding the best nest probably because they could deploy more scouts. As a result, large colonies in nature probably find more of the available nests more quickly than small colonies. Thus larger colonies may have a greater tendency to split than small colonies. Large colonies, however, used larger quorum thresholds to make collective decisions than smaller colonies. Higher quorum thresholds should help to reduce splitting by large colonies. Large colonies also used more reverse tandem runs, a process for recruitment of more active participants into emigrations. More reverse tandem runs may help large colonies to reunite if they do split. In a second experiment, large and small colonies had almost identical preferences for nests with a floor area that would ideally accommodate a fully grown colony. Thus, small colonies behaved in a way that seemed to anticipate their future needs, when they would have grown to fill a larger space. © 2006 The Association for the Study of Animal Behaviour.
• Franks, N. R., Dornhaus, A., Metherell, B. G., Nelson, T. R., A., S., & Symes, W. S. (2006). Not everything that counts can be counted: Ants use multiple metrics for a single nest trait. Proceedings of the Royal Society B: Biological Sciences, 273(1583), 165-169.
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  Abstract: There are claims in the literature that certain insects can count. We question the generality of these claims and suggest that summation rather than counting (sensu stricto) is a more likely explanation. We show that Temnothorax albipennis ant colonies can discriminate between potential nest sites with different numbers of entrances. However, our experiments suggest that the ants use ambient light levels within the nest cavity to assess the abundance of nest entrances rather than counting per se. Intriguingly, Weber's Law cannot explain the ants' inaccuracy. The ants also use a second metric, independent of light, to assess and discriminate against wide entrances. Thus, these ants use at least two metrics to evaluate one nest trait: the configuration of the portals to their potential homes. © 2005 The Royal Society.
• Marshall, J. A., Dornhaus, A., Franks, N. R., & Kovacs, T. (2006). Noise, cost and speed-accuracy trade-offs: Decision-making in a decentralized system. Journal of the Royal Society Interface, 3(7), 243-254.
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  PMID: 16849234;PMCID: PMC1578745;Abstract: Many natural and artificial decision-making systems face decision problems where there is an inherent compromise between two or more objectives. One such common compromise is between the speed and accuracy of a decision. The ability to exploit the characteristics of a decision problem in order to vary between the extremes of making maximally rapid, or maximally accurate decisions, is a useful property of such systems. Colonies of the ant Temnothorax albipennis (formerly Leptothorax albipennis) are a paradigmatic decentralized decision-making system, and have been shown flexibly to compromise accuracy for speed when making decisions during house-hunting. During emigration, a colony must typically evaluate and choose between several possible alternative new nest sites of differing quality. In this paper, we examine this speed-accuracy trade-off through modelling, and conclude that noise and time-cost of assessing alternative choices are likely to be significant for T. albipennis. Noise and cost of such assessments are likely to mean that T. albipennis' decision-making mechanism is Pareto-optimal in one crucial regard; increasing the willingness of individuals to change their decisions cannot improve collective accuracy overall without impairing speed. We propose that a decentralized control algorithm based on this emigration behaviour may be derived for applications in engineering domains and specify the characteristics of the problems to which it should be suited, based on our new results. © 2005 The Royal Society.
• Planque, R., Marshall, J. A., Kovacs, T., Franks, N. R., & Dornhaus, A. (2006). Weighting waiting in collective decision-making. Behavioral Ecology and Sociobiology, 61(3), 347-356. doi:10.1007/s00265-006-0263-4
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  Animals searching for food, mates, or a home often need to decide when to stop looking and choose the best option found so far. By re-analyzing experimental data from experiments by Mallon et al. (Behav Ecol Sociobiol 50:352–359, 2001), we demonstrate that house-hunting ant colonies are gradually more committed to new nests during the emigration. Early in house-hunting, individual ants were flexibly committed to new nest sites. However, when carrying to a new nest had started, ants hardly ever switched preference. Using a theoretical model based on experimental data, we test at which stage flexible commitment influences speed and accuracy most. We demonstrate that ant colonies have found a good compromise between impatience and procrastination. Early flexibility combined with later rigidity is identically effective as other strategies that include flexible commitment, but it is particularly good when emigration conditions are harsh.
• Raine, N. E., Ings, T. C., Dornhaus, A., Saleh, N., & Chittka, L. (2006). Adaptation, Genetic Drift, Pleiotropy, and History in the Evolution of Bee Foraging Behavior. Advances in the Study of Behavior, 36, 305-354.
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  Abstract: Our goal in this chapter is to determine whether particular behavioral traits represent actual adaptations in the context of foraging. Social bees are our chosen study system because they provide a convenient and tractable biological system with which to study the potential adaptiveness of a wide range of foraging traits such as flower constancy, floral color preference, learning to associate floral color as a predictor of reward, traplining, and communication about food sources. This variety of behavioral traits allows us to demonstrate the strengths and weaknesses of applying five approaches (four experimental and one theoretical) to the study of foraging at the species, population, and colony level. (1) The comparative approach allows us to contrast behavioral traits of extant species with those of their common ancestor. We correlated differences in floral color preference between closely related species (and populations), with a known phylogeny, with features in each bee's respective environment. (2) Reciprocal transplant experiments allowed us to test for local adaptation. We compared the relative foraging performance of distinct bee populations in both of their respective native environments. (3) Manipulating the foraging environment to eliminate specific behavioral traits permitted a direct comparison of animals' foraging performance in their normal and experimentally manipulated environment, allowing us to quantify the effect of the trait in question (traplining) on foraging performance. (4) Manipulating the foraging phenotype to eliminate specific behavioral traits is another valuable approach. Unless suitable behavioral mutants, knockouts, or molecular techniques to selectively block gene expression are available, creating such artificial foraging phenotypes is only possible for a very small number of specific traits, for example, the honeybee dance language. (5) Integrating biologically realistic modeling with experimental studies allows us to test predictions about the adaptive significance of foraging-related traits not amenable to experimental manipulation and to identify the ranges over which these traits might affect fitness. Do these approaches provide evidence that foraging behaviors are adaptive? In some cases, we show that forager behavior has indeed been tuned to function adaptively in a given niche, although the adaptive benefits of such behavioral traits are often strongly context dependent. However, in other cases, the observed patterns of behavior were more parsimoniously explained by chance evolutionary processes, or by the historical conditions under which bees operated in their evolutionary past. © 2006 Elsevier Inc. All rights reserved.
• Dechaume-Moncharmont, F., Dornhaus, A., Houston, A. I., McNamara, J. M., Collins, E. J., & Franks, N. R. (2005). The hidden cost of information in collective foraging. Proceedings of the Royal Society B: Biological Sciences, 272(1573), 1689-1695.
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  PMID: 16087424;PMCID: PMC1559855;Abstract: Many animals nest or roost colonially. At the start of a potential foraging period, they may set out independently or await information from returning foragers. When should such individuals act independently and when should they wait for information? In a social insect colony, for example, information transfer may greatly increase a recruit's probability of finding food, and it is commonly assumed that this will always increase the colony's net energy gain. We test this assumption with a mathematical model. Energy gain by a colony is a function both of the probability of finding food sources and of the duration of their availability. A key factor is the ratio of pro-active foragers to re-active foragers. When leaving the nest, pro-active foragers search for food independently, whereas re-active foragers rely on information from successful foragers to find food. Under certain conditions, the optimum strategy is totally independent (pro-active) foraging because potentially valuable information that re-active foragers may gain from successful foragers is not worth waiting for. This counter-intuitive outcome is remarkably robust over a wide range of parameters. It occurs because food sources are only available for a limited period. Our study emphasizes the importance of time constraints and the analysis of dynamics, not just steady states, to understand social insect foraging. © 2005 The Royal Society.
• Dornhaus, A., & Chittka, L. (2005). Bumble bees (Bombus terrestris) store both food and information in honeypots. Behavioral Ecology, 16(3), 661-666.
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  Abstract: Social insect foragers often transmit information about food sources to nest mates. In bumble bees (Bombus terrestris), for example, successful foragers use excited motor displays and a pheromone as communication signals. In addition, bees could make use of an indirect pathway of information flow, via the honey stores. We show here that, indeed, bees in the nest continuously monitor honeypots and sample their contents, thus obtaining information on supply and demand of nectar. When there is an influx of nectar into the nest, the colony deploys more workers for foraging. The number of new foragers depends on sugar concentration. Foragers returning with high-quality sugar solution display more "excited runs" on the nest structure. The recruits' response, however, does not depend on modulated behavior by foragers: more workers start to forage with high quality of incoming nectar, even when this nectar is brought by a pipette. Moreover, we show that the readiness of bees to respond to recruitment signals or incoming nectar also depends on colony demand. When colony nectar stores are full, the response of bees to equal amounts of nectar influx is smaller than when stores are empty. When colony nectar stores are depleted, foragers spend more time running excitedly and less time probing pots in the nest and run with higher average speed, possibly to disperse the alerting pheromone more efficiently. However, more bees respond to nectar influx to empty stores, whether or not this is accompanied by forager signals. Thus, honeypots serve to store information as well as food. © The Author 2005. Published by Oxford University Press on behalf of the International Society for Behavioral Ecology. All rights reserved.
• Franks, N. R., Hooper, J., Webb, C., & Dornhaus, A. (2005). Tomb evaders: House-hunting hygiene in ants. Biology Letters, 1(2), 190-192.
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  PMID: 17148163;PMCID: PMC1626204;Abstract: House-hunting ants avoid otherwise excellent potential nest sites that contain dead ants which may pose risks from poor hygiene. This discovery adds another category to the exceptionally long list of nest site attributes that ants evaluate. It further indicates the importance of disease as a selection pressure on social insects. © 2005 The Royal Society.
• Granero, A. M., M., J., J., F., L., J., Dornhaus, A., Ghani, J., Serrano, A. R., & Chittka, L. (2005). Chemical compounds of the foraging recruitment pheromone in bumblebees. Naturwissenschaften, 92(8), 371-374.
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  PMID: 16049691;Abstract: When the frenzied and irregular food-recruitment dances of bumblebees were first discovered, it was thought that they might represent an evolutionary prototype to the honeybee waggle dance. It later emerged that the primary function of the bumblebee dance was the distribution of an alerting pheromone. Here, we identify the chemical compounds of the bumblebee recruitment pheromone and their behaviour effects. The presence of two monoterpenes and one sesquiterpene (eucalyptol, ocimene and farnesol) in the nest airspace and in the tergal glands increases strongly during foraging. Of these, eucalyptol has the strongest recruitment effect when a bee nest is experimentally exposed to it. Since honeybees use terpenes for marking food sources rather than recruiting foragers inside the nest, this suggests independent evolutionary roots of food recruitment in these two groups of bees. © Springer-Verlag 2005.
• Dornhaus, A., & Chittka, L. (2004). Information flow and regulation of foraging activity in bumble bees (Bombus spp.). Apidologie, 35(2), 183-192.
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  Abstract: Communication in the context of foraging in bumble bees has received less attention than in other social bees. Yet, recent studies have revealed that information flow mediates colony foraging activity. The species studied do not recruit to specific locations, but bees can learn the scent of food sources at the nest, which may reduce their search time. Location communication may not confer high benefits to bumble bees. But bees react to nectar influx with increased foraging activity, with high quality food eliciting more activity. This shows that bees recognize and sample freshly collected nectar. If the colony has no demand for food, foraging activity does not increase. Successful foragers distribute a tergal gland pheromone in the nest that also elicits higher foraging activity. Information exchange in the nest thus enables bumble bees to base their decision to forage on demand and the presence and profitability of food.
• Dornhaus, A., & Chittka, L. (2004). Why do honey bees dance?. Behavioral Ecology and Sociobiology, 55(4), 395-401.
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  Abstract: The honey bee dance language, used to recruit nestmates to food sources, is regarded by many as one of the most intriguing communication systems in animals. What were the ecological circumstances that favoured its evolution? We examined this question by creating experimental phenotypes in which the location information of the dances was obscured. Surprisingly, in two temperate habitats, these colonies performed only insignificantly worse than colonies which were able to communicate normally. However, foraging efficiency was substantially impaired in an Asian tropical forest following this manipulation. This indicates that dance language communication about food source locations may be important in some habitats, but not in others. Combining published data and our own, we assessed the clustering of bee forage sites in a variety of habitats by evaluating the bees' dances. We found that the indicated sites are more clustered in tropical than in temperate habitats. This supports the hypothesis that in the context of foraging, the dance language is an adaptation to the particular habitats in which the honey bees evolved. We discuss our findings in relation to spatial aggregation patterns of floral food in temperate and tropical habitats.
• Dornhaus, A., Franks, N. R., Hawkins, R. M., & Shere, H. N. (2004). Ants move to improve: Colonies of Leptothorax albipennis emigrate whenever they find a superior nest site. Animal Behaviour, 67(5), 959-963.
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  Abstract: A high-quality home can be a major factor determining fitness. However, when house hunting becomes necessary, animals might often face a speed-versus-accuracy trade-off and therefore be unable to survey their environment extensively for the optimum site. We found that the ant Leptothorax albipennis was able to correct errors made in such a hurried decision by continuing to survey even after a colony had settled in a nest site. Colonies moved from intact undisturbed nests to another nest site whenever the new nest site presented a sufficient improvement in nest quality. Thus, scout ants must be able to judge and compare the quality of the new, empty nest site with the one currently inhabited by the colony. Emigrations from intact nests were initiated by high numbers of ants recruited by tandem runs. This evidence may explain how a small number of scouts can motivate an entire colony to move when there is no immediate need to do so. Compared with their behaviour in emigrations from destroyed nests, the ants favoured even more strongly accuracy over speed, because they waited for a larger number of scouts to agree on one site before starting the emigration. They could do this without increased risk because the rest of the colony remained safely in the old nest. © 2004 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
• A., J., Kovacs, T., Dornhaus, A. R., & Franks, N. R. (2003). Simulating the evolution of ant behaviour in evaluating nest sites. Lecture Notes in Artificial Intelligence (Subseries of Lecture Notes in Computer Science), 2801, 643-650.
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  Abstract: When an ant colony needs to find a new nest, scouts are sent out to evaluate the suitability of potential sites, particularly their size. It has been suggested that ant scouts of Leptothorax albipennis use a simple heuristic known as Buffon's needle to evaluate nest size. They do this in two stages: first laying a pheromone trail in the nest site, then, after a return to the old nest, coming back and wandering within the site assessing frequency of intersection with the pheromone trail ("two-pass" strategy). If a colony is forced to relocate from its current nest due to destruction of that nest, the time required to find a suitable new nest may be crucial. This paper details preliminary results from a computer simulation model of evaluation of nest size. The model aims to study why a "two-pass" strategy is used by ants when a "one-pass" strategy, in which the ant simultaneously lays pheromone and assesses the frequency at which it encounters its own trail, may be more time efficient. Analysis of the results indicates no clear advantage for the "two-pass" strategy, given the assumptions of the model. Possible implications of this result are discussed.
• Chittka, L., Dyer, A. G., Bock, F., & Dornhaus, A. (2003). Bees trade off foraging speed for accuracy. Nature, 424(6947), 388-.
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  PMID: 12879057;
• Dornhaus, A., & Cameron, S. (2003). A scientific note on food alert in Bombus transversalis. Apidologie, 34(1), 87-88.
• Dornhaus, A., Brockmann, A., & Chittka, L. (2003). Bumble bees alert to food with pheromone from tergal gland. Journal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology, 189(1), 47-51.
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  PMID: 12548429;Abstract: Foragers of Bombus terrestris are able to alert their nestmates to the presence of food sources. It has been supposed that this happens at least partially through the distribution of a pheromone inside the nest. We substantiate this claim using a behavioral test in which an alerting signal is transmitted from one colony to another by long distance air transport, so excluding all other modalities of information exchange. We then investigated the source of the pheromone and were able to show that a hexane extract from tergites V-VII of bumble bee workers elicits higher activity, like a successful forager does. Extracts from other glands, such as the mandibular, labial, hypopharyngeal, and Dufour's gland as well as extracts from other parts of the cuticle had no effect. This suggests that bumble bees possess a pheromone-producing gland, similar to the Nasanov gland in honey bees. Indeed, an extract from the honey bee Nasanov gland also proved to alert bumblebee workers, suggesting a possible homology of the glands.
• Franks, N. R., & Dornhaus, A. (2003). How might individual honeybees measure massive volumes?. Proceedings of the Royal Society B: Biological Sciences, 270(SUPPL. 2), s181-s182.
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  PMID: 14667376;PMCID: PMC1809947;Abstract: We suggest how individual honeybees might measure the large volumes of potential nest sites and propose a key experimental test for our model.
• Franks, N. R., Dornhaus, A., Fitzsimmons, J. P., & Stevens, M. (2003). Speed versus accuracy in collective decision making. Proceedings of the Royal Society B: Biological Sciences, 270(1532), 2457-2463.
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  PMID: 14667335;PMCID: PMC1691524;Abstract: We demonstrate a speed versus accuracy trade-off in collective decision making. House-hunting ant colonies choose a new nest more quickly in harsh conditions than in benign ones and are less discriminating. The errors that occur in a harsh environment are errors of judgement not errors of omission because the colonies have discovered all of the alternative nests before they initiate an emigration. Leptothorax albipennis ants use quorum sensing in their house hunting. They only accept a nest, and begin rapidly recruiting members of their colony, when they find within it a sufficient number of their nest-mates. Here we show that these ants can lower their quorum thresholds between benign and harsh conditions to adjust their speed-accuracy trade-off. Indeed, in harsh conditions these ants rely much more on individual decision making than collective decision making. Our findings show that these ants actively choose to take their time over judgements and employ collective decision making in benign conditions when accuracy is more important than speed.
• Dornhaus, A. (2002). Significance of honeybee recruitment strategies depending on foraging distance (Hymenoptera: Apidae: Apis mellifera). Entomologia Generalis, 26(2), 93-100.
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  Abstract: The importance of the spatial information which is communicated in the Camolian Race of the Western Honeybee, Apis mellifera carnica (Pollmann 1879) waggle dance relative to other cues used by bees in finding food sources was investigated. The efficiency of recruitment with and without transmission of direction information in the waggle dance was quantified using artificial, plentiful unscented food sources and hives which were turned to a horizontal position to disrupt orientation of dancing bees and thereby eliminate the spatial information from dances. Transmission of location information seems to improve recruitment effect particularly at large distances. Recruitment declines more rapidly with distance if dances are disoriented, and for large distances it takes a few hours before a foraging group is established. However, this shows that even without dance information, foragers manage to recruit some bees to their food source. This process, however, is so slow that by the time a group of recruits has reached the food source, it may not be worth exploiting any more. Transmission of spatial information thus is especially important if distant food sources which often change in nectar availability are exploited.
• Dornhaus, A., & Chittka, L. (2001). Food alert in bumblebees (Bombus terrestris): Possible mechanisms and evolutionary implications. Behavioral Ecology and Sociobiology, 50(6), 570-576.
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  Abstract: The return of a successful bumblebee forager stimulates nestmates to leave the nest and search for food. Here we investigate the mechanisms by which this happens. Successful Bombus terrestris foragers perform irregular runs in their nest, often lasting for several minutes. Run duration is at its maximum when food has just been discovered. Running likely serves to distribute a pheromone, since the information flow between "runners" and "recruits" can be disrupted by eliminating air exchange, while leaving other potential means of communication intact. In addition, nectar stores in the nest may be monitored continuously. A sudden influx of nectar into the nest also causes measurable increases in forager activity. The implications of bumblebee recruitment behavior for the evolution of communication in bees are discussed.
• Dornhaus, A., & Chittka, L. (1999). Evolutionary origins of bee dances. Nature, 401(6748), 38-.

Proceedings Publications

• Su, L., Su, H., Lynch, N., & Dornhaus, A. (2017). Ant-Inspired Dynamic Task Allocation via Gossiping. In Stabilization, Safety, and Security of Distributed Systems - 19th International Symposium, SSS 2017, Proceeding, 157-171.
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  We study the distributed task allocation problem in multi-agent systems, where each agent selects a task in such a way that, collectively, they achieve a proper global task allocation. In this paper, inspired by specialization on division of labor in ant colonies, we propose several scalable and efficient algorithms to dynamically allocate the agents as the task demands change. The algorithms have their own pros and cons, with respect to (1) how fast they react to dynamic demands change, (2) how many agents need to switch tasks, (3) whether extra agents are needed, and (4) whether they are resilient to faults.
• Fasciano, T., Dornhaus, A., & Shin, M. C. (2014, Spring). Ant tracking with occlusion tunnels. In IEEE Winter Conference on Applications of Computer Vision, 947-52.
• Hoan, N., Fasciano, T., Charbonneau, D., Dornhaus, A., & Shin, M. C. (2014, Spring). Data association based ant tracking with interactive error correction. In IEEE Winter Conference on Applications of Computer Vision, 941-6.
• Fasciano, T., Dornhaus, A. R., & Shin, M. C. (2015, Spring). Multiple Insect Tracking with Occlusion Sub-tunnels. In IEEE Winder Conference on Applications of Computer Vision.
• Rice, L., Dornhaus, A., & Shin, M. C. (2015, Fall). Efficient Training of Multiple Ant Tracking. In IEEE Winder Conference on Applications of Computer Vision.

Presentations

• Dunlap, A. S., Dornhaus, A. R., & Papaj, D. R. (2011, June). Effects of reliability on whether to follow social or floral signals in foraging bumblebees. International Conference, Social Decision Making: Bridging Economics and Evolutionary Biology. Monte Verita, Switzerland.
• Dunlap, A. S., Dornhaus, A. R., & Papaj, D. R. (2011, June). When to acquire new information? How persistence and reward affect sampling and tracking in foraging bumblebees. 18th Annual International Conference on Comparative Cognition. Melbourne, FL.
• Leonard, A. S., Dornhaus, A. R., & Papaj, D. R. (2010, July). Odors facilitate perception of color cues in bumble bees. International Society of Behavioral Ecology, Triennial Meeting. Perth Australia: International Society of Behavioral Ecology.
• Leonard, A. S., Dornhaus, A. R., & Papaj, D. R. (2010, August). Signal detectability and the function of complex floral signals. Animal Behavior Society, Annual Meeting. Williamsburg, VA: Animal Behavior Society.
• Papaj, D. R., Dornhaus, A. R., & Dunlap, A. S. (2010, July). When to acquire new information? How persistence and reward affect sampling, tracking, and constancy in bumblebees. Meeting, International Union for the Study of Social Insects. Copenhagen, Denmark: International Union for the Study of Social Insects.
• Papaj, D. R., Leonard, A. S., & Dornhaus, A. R. (2010, August). Floral complexity, speed-accuracy tradeoffs, and the neuroeconomics of nectar-foraging in bees. Animal Behavior Society, Annual Meeting. Williamsburg, VA: Animal Behavior Society.

Poster Presentations

• Papaj, D. R., Leonard, A. S., & Dornhaus, A. R. (2011, July). Speed-accuracy tradeoffs and nectar-foraging in bees: merging neuroeconomics with optimality theory. Gordon Conference on Neuroethology and Evolution. Eaton, MA: Gordon Conferences.
• Dunlap, A. S., Papaj, D. R., & Dornhaus, A. R. (2010, May). Tracking of a variable environment: experiments with bees. Workshop on Social Biomimicry: Insect Societies and Human Design,. Tempe, AZ: Arizona State University.
• Kaczorowski, R. L., Leonard, A. S., Dornhaus, A. R., & Papaj, D. R. (2010, July). Do bumblebees match their foraging movements to the scale of resource patchiness?. Animal Behavior Society National Meeting. Bloomington, IN: Animal Behavior Society.

Reviews

• Bengston, S. E., Jandt, J., & Dornhaus, A. (2011. Book review of: Food exploitation by Social Insects: Ecological, Behavioral, and Theoretical Approaches(pp 359-359).
• Dornhaus, A. R. (2011. Book review of: The buzz about bees(pp 86: 59).