Comparing the Ephemeroptera and Plecoptera specimen databases at the Illinois natural history survey and using them to document changes in the Illinois Fauna

Databasing of all Ephemeroptera and Plecoptera specimens in the Illinois Natural History Survey Insect Collection has recently been completed. Both databases are Internet-searchable in a simplified format (http://www.inhs.uiuc. edu/cbd/EPT/index.html). Analysis of the databases shows that the Plecoptera are at a much better level of determination than the Ephemeroptera, with 88% of the specimens determined to the species level. Only 22% of Ephemeroptera specimens have been determined to species. The Ephemeroptera collection is also much more narrow in geographic scope, with 74% of determined specimens from Illinois. In contrast, only 30% of determined Plecoptera specimens are from Illinois, with most of the remainder being from across the United States. Four new Illinois records were uncovered in the Ephemeroptera database: Caenis diminuta Walker, C. punctata McDunnough, Pseudoclocon ephippiatum (Traver), and Serratella deficiens (Morgan). Analyses of the data document range reductions in Illinois of the stonefly Neoperla clymene (Newman) and the mayfly Pseudiron centralis McDunnough, range expansion in the stonefly Perlesta nclsoni Stark, and a shift in the prevalence of perlid stonefly species assemblages from Acroneuria in the first half of the 20th century to Perlesta in the second half. We also discuss the change in Plecoptera diversity between historic and modern records from Illinois, and compare the relative stability of Plecoptera species assemblages from the major ecological regions of the state. We encourage entomologists to find other uses for these data and to contribute a growing pool of historic specimen-level data at their own institutions.