Rediscovery of Stactobia eatoniella McLachlan, 1880 (Trichoptera, Hydroptilidae) in Switzerland after more than seventy years

Abstract

A specimen of Stactobia eatoniella, a hygropetric species of micro-caddisfly considered extinct in Switzerland, was discovered in the Morge in Valais in March 2020 during routine monitoring. This last instar larva in perfect condition is the first to be observed in Switzerland since 1944. Further research in the study area is needed to confirm the presence of a possible well-established population. This encouraging discovery should not hide the fact that two thirds of the micro-caddisfly species are on the Red List of threatened species of Switzerland, and that hygropetric habitats are both under-studied and highly endangered in Switzerland and worldwide.