Coelioxys alatus Förster, 1853 (Hymenoptera: Megachilidae) recorded in Sweden for the first time

Abstract

During an insect inventory in the summer of 2019, a female Coelioxys alatus Förster, 1853 was caught in a pan trap close to Råstasjön in Solna. This is the first record of the species in Sweden. C. alatus is distributed across large parts of Europe and Asia but has always been considered as a rare species. The closest occurrences from a Swedish perspective are from Finland and Estonia, where the species seem to have increased in numbers during recent decades and possibly also expanded the distribution area westwards. C. alatus is a cleptoparasite on Megachile ligniseca (Kirby, 1802), which preferably nests in cavities in dead wood. A large share of the European records of C. alatus have been made at localities close to wetlands such as marshlands, ponds and rivers. Whether the Swedish record of C. alatus is the result of a westward expansion of the former distribution area or if it has arrived in Sweden with imported timber is currently unknown. It is, however, possible that C. alatus occurs at more sites, such as the eastern parts of Svealand.