Monitoring of Pachybrachis Chevrolat (Coleoptera: Chrysomelidae: Cryptocephalinae) Diversity and Abundance in Illinois for 140 Years: Recent Detections and Presumed Extirpations

Abstract Thirty-three species of Pachybrachis Chevrolat were collected in Illinois between 1881 and 2020. A historical, or longitudinal, perspective in 20-year increments is presented for each species. The species can be subdivided into three cohorts based upon their relative consistency of collection over time. Ten species have been recovered consistently over this extended timeframe, eleven species were just found in Illinois since 1950, and twelve species (36.4%) were no longer found during the last 20 years of targeted collecting and are presumed extirpated.