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Seasonal Abundance of Tabanus calens and Other Tabanidae (Diptera) Near Snake Mountain, Addison County, Vermont

Freeman, Jeffrey V.
Northeastern naturalist 2017 v.24 no.2 pp. 137-151
Chrysops, Hybomitra, Tabanus, baits, horses, Vermont
Weekly collections, from May to September over 3 years from one 2-tier box trap in Addison, VT, totaled more than 29,000 tabanids representing 44 species and included 417 Tabanus calens. Seasonal succession was evident, with T. calens most numerous in the upper trap in August. This very large horse fly was easily collected around a bait horse with an aerial net. Other abundant horse fly species were Hybomitra lasiophthalma, T. quinquevittatus, T. lineola, and T. sackeni. The most abundant deer flies were Chrysops univittatus and C. vittatus. Most deer flies showed a preference for the upper trap, whereas horse flies showed a mixed preference. Tabanus quinquevittatus made up 60% of the collected horseflies in the trap. The trap collected 41% less horse flies (73% less T. calens) and 24% less deer flies with the trap in 2013 to compared to in 2015. Both the presence of T. calens and the use of the 2-tier box trap in Vermont at one site for 3 whole seasons were new events. Tabanus calens was not listed in the 1990 checklist of Vermont tabanids. These results are presented in the context of trap modifications, range extension, and polarized light.