New record of Pachodynerus nasidens (Vespidae) on Madeira

Native to the Americas, P. nasidens has demonstrated a remarkable capacity for range expansion, with established populations in several Pacific islands, Japan, and Australia. Its detection in Madeira represents the first occurrence of this species in the western Palaearctic, the first introduced species of Vespidae recorded on Madeira Island, and only the second in Macaronesia.

The introduction of P. nasidens is likely linked to human-mediated transport, particularly via aviation and maritime activities, which facilitate dispersal across oceanic barriers. The species’ notable nesting plasticity—allowing it to exploit pre-existing cavities, abandoned nests of other wasps, and various artificial structures—is considered a key factor underlying its successful establishment in novel insular environments.