Tristan Mcknight

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• Mcknight, T., & Cannings, R. A. (2020). Molecular phylogeny of the genus Lasiopogon (Diptera: Asilidae) and a taxonomic revision of the bivittatus section. Zootaxa, 4835(1), 1-115. doi:https://doi.org/10.11646/zootaxa.4835.1
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  Nearctic species of Lasiopogon Loew comprising the bivittatus section (the bivittatus group sensu Cannings 2002) are revised, with the description of 13 new species, elevation of one subspecies to species, and redescriptions of 13 previously described taxa. An updated key to western Nearctic Lasiopogon adults is provided, as are notes on taxonomy, distribution, phylogeny, and ecology. A Bayesian species tree for 67 species of Lasiopogon is estimated from one mitochondrial (COI) and three nuclear protein-coding loci (AATS, PEPCK, Wg), and compared to a previously published morphology-based phylogeny. The following new species of Lasiopogon are described (assigned to the bivittatus section except as noted): L. anaphlecter sp. nov., L. apoecus sp. nov., L. asilomar sp. nov., L. bitumineus sp. nov., L. canningsi sp. nov., L. condylophorus sp. nov., L. esau sp. nov., L. karli sp. nov. (assigned to cinereus group of opaculus section), L. nelsoni sp. nov., L. odontotus sp. nov., L. sierra sp. nov., L. tumulicola sp. nov., L. wilcoxi sp. nov.; L. puyallupi Cole & Wilcox 1938 stat. nov. is elevated from subspecies; and the following previously described species are considered valid: L. actius Melander 1923, L. albidus Cole & Wilcox 1938, L. arenicola (Osten Sacken 1877), L. bivittatus Loew 1866, L. californicus Cole & Wilcox 1938, L. dimicki Cole & Wilcox 1938, L. drabicolum Cole 1916, L. gabrieli Cole & Wilcox 1938, L. littoris Cole 1924, L. ripicola Melander 1923, L. willametti Cole & Wilcox 1938, L. zonatus Cole & Wilcox 1938. The species L. martinensis Cole & Wilcox 1938 is considered valid but transferred to the tetragrammus group of the opaculus section.
• Haab, K. A., McKnight, T. A., & McKnight, K. B. (2019). Phenology and Ethology of Adult Lasiopogon slossonae Cole and Wilcox Robber Flies (Diptera: Asilidae) in a New York Riparian Habitat. Proceedings of the Entomological Society of Washington, 121(4), 594-615. doi:https://doi.org/10.4289/0013-8797.121.4.594
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  Seasonal abundance, daily activity, and behavior of adults of the robber fly Lasiopogon slossonae Cole and Wilcox were assessed with a capture-mark-recapture procedure for a population along 1 km of riverside in the Adirondack Mountains near Lake Placid, New York. Over the 2015 season, a total of 240 individuals were uniquely marked at this site; 73 were re-sighted at least one more time. The overall emergence window for this population in 2015 spanned 47 days with a maximum individual lifespan observed of 23 days; adult seasonal phenology periods for three other years are also summarized from presence/absence observations. In 2015, the adult sex ratio was slightly male-skewed (58%), but there was no significant difference between the sexes in home range size or perch distance from water. Flies packed more tightly into microhabitat patches as the overall abundance increased, and individuals showed some fidelity to relatively small home ranges (the median area of activity for marked individuals was 20 m2). However, longer dispersal also occurred rarely—the farthest movement we observed was 726 m over nine days. Individuals were active from morning to evening (usually 10:00 to 18:00) with a daily activity period that appeared to depend on both light intensity and temperature. Prey consisted mostly of Empididae, but also included Simuliidae, Anthomyiidae, and Cicadellidae. Both males and females were observed mating with multiple partners on different days.
• Clement, R. A., Frandsen, P. B., McKnight, T. A., & Nelson, C. R. (2018). Fly family diversity shows evidence of livestock grazing pressure in Mongolia (Insecta: Diptera). Journal of Insect Conservation, 22(2), 231-243. doi:https://doi.org/10.1007/s10841-018-0056-x
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  Members of the insect order Diptera respond differentially to environmental changes and may play an important role in understanding the effects that livestock grazing disturbances have on biodiversity. Here we examine how increasing grazing pressures on the Mongolian steppe affect Diptera diversity and abundance. Using 2334 yellow pan traps, we sampled a total of 132 sites over four years to collect 17,348 flies. We compared fly diversity and abundance at five levels of livestock grazing. We observed that fly family diversity decreased in heavily grazed sites and that diptera communities at sites with intense grazing have proportionally higher prevalence of taxa from the families Muscidae, Sepsidae, Ephydridae, Chloropidae, and Tachinidae, two of which are often associated with animal waste. Chironomidae, Ceratopogonidae, Sarcophagidae, and Sciaridae are most prevalent at sites with very little or no grazing, and Anthomyiidae, Calliphoridae, Carnidae, Cecidomyiidae, Dolichopodidae, Empididae, Scatopsidae and Sphaeroceridae are most often encountered at sites with intermediate amounts of grazing. Observing changes in a few guilds of fly families at different grazing levels is beneficial in understanding human effects on fly diversity.
• McKnight, T. A., & Cannings, R. A. (2017). Description and phylogenetic classification of Stackelberginia cerberus sp. nov. (Diptera: Asilidae), comprising the first record of this genus from the Nearctic. Zootaxa, 4306(4), 567-579. doi:http://dx.doi.org/10.11646/zootaxa.4306.4.7
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  Stackelberginia cerberus sp. nov. (Diptera: Asilidae) is described from the Amargosa desert (USA: Nevada) and compared to related taxa. This is the first record of the genus in the Western Hemisphere; other species live in the deserts of central Asia. Stackelberginia Lehr is proposed as the sister taxon to Lasiopogon Loew in the subfamily Stichopogoninae based on morphological characters and a Bayesian species tree estimated from one mitochondrial (COI) and three nuclear protein-coding loci (AATS, PEPCK, wingless). Stackelberginia has the medially divided epandrium and rotated hypopygium of Lasiopogon, but the facial gibbosity is flat, macrosetae of thorax, head, and legs are unusually long, and phenology peaks in late autumn. 
• McKnight, T. A., McKnight, K. B., & Skeels, M. C. (2010). Amatoxin and phallotoxin concentration in Amanita bisporigera spores. Mycologia, 102(4), 763-765. doi:http://dx.doi.org/10.3852/09-131
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  Even though amatoxins and phallotoxins have been well characterized in basidiocarps of Amanita species, to our knowledge no report of these toxins in spores of Amanitas has been published. Reversed phase HPLC was used to determine nonzero concentrations of α-amanitin (0.30 mg/g), and phallacidin (0.02 mg/g) in spores taken from white Amanita sect. phalloideae species. We did not find significant amounts of phalloidin in Amanita spores. We also report concentrations of these toxins from pileus and stipe tissues that are similar to previously reported values, lending support to the hypothesis that toxin concentrations in spores are much less than in other basidiocarp tissues.