Adventive and native Byrrhidae (Coleoptera) newly recorded from Prince Edward Island, Canada

The Palearctic byrrhids Chaetophora spinosa (Rossi) and Simplocaria semistriata (F.) are reported for the first time from Prince Edward Island (PEI), the former species for the first time from Atlantic Canada from specimens collected in 2003‐05. Their presence is discussed both in light of the history of introductions of exotic species in Atlantic Canada in general, and on PEI in particular, and also in the context of the effect of adventive species on native organisms and ecosystems. These discoveries underscore the need for continual monitoring of invertebrate populations to detect ongoing introductions of adventive species. The native byrrhid Cytilus alternatus (Say) is also reported for the first time from PEI.