An analytical synopsis of caddisfly (Insecta, Trichoptera) taxonomic history and progress in Canada and the United States

Abstract

A total of 1,510 caddisfly species representing 28 families and 155 genera are reported from the 63 states and provinces of Canada and the United States of America (USA). These species have been described over a period of nearly 270 years, with the most prolific period occurring during the 1930–1940s. The families Hydroptilidae (307), Limnephilidae (255), and Hydropsychidae (159) contain the most species, whereas six families contain less than five species each. Canada and the USA host 644 and 1,487 species, respectively. The states and provinces with the greatest species richness are Tennessee (384), Virginia (383), and Alabama (378), and those with the least are Rhode Island (27), Prince Edward Island (23), and Nunavut (15). Differences in state species assemblages largely followed a geographic pattern, with a non-metric multidimensional scaling ordination suggesting six regions of caddisfly diversity corresponding to the central, far north, northeastern, northwestern, southeastern, and southwestern portions of the study area. Caddisfly species richness was highest in the southeastern region, despite being the smallest region of the six, and lowest in the far north. Species rarefaction predicted 129–181 species remain to be discovered within the two countries, while multiple linear regression modeling using common environmental variables suggested 17 states and provinces with at least 50 species remaining to be found in each.

Affiliated Institutions

• Emory University US
• University of Illinois Urbana-Champaign US
• Hillsdale College US
• Florida Agricultural and Mechanical University US
• Illinois Archaeological Survey US
• Clemson University US

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