Short Communication |
Corresponding author: Laurent Vuataz ( laurent.vuataz@vd.ch ) Academic editor: Jean-Luc Gattolliat
© 2021 Laurent Vuataz, Pascal Stucki, Lucie Fauquet, Régine Bernard.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Vuataz L, Stucki P, Fauquet L, Bernard R (2021) Rediscovery of Stactobia eatoniella McLachlan, 1880 (Trichoptera, Hydroptilidae) in Switzerland after more than seventy years. Alpine Entomology 5: 55-60. https://doi.org/10.3897/alpento.5.67985
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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.
caddisfly, benthic macroinvertebrates, crenic habitats, petrimadicolous, stream, survey
The Swiss fauna includes 302 species of caddisflies (
The genus Stactobia McLachlan, 1880 currently consists of 168 species, 41 of which are in the Western Palearctic (
Before the rediscovery of S. eatoniella reported here, eight observations between 1888 and 1944 were officially recorded in Switzerland (
As part of the surface water quality monitoring of the Canton du Valais, the "Service de l’environnement" (SEN) commissioned the consultancy office "biol conseils" to conduct samplings of benthic macroinvertebrates in the Morge catchment using the Swiss biotic index (IBCH method;
One last instar larva of S. eatoniella was found at the site located below the place called Cernet Dessous (Morge, site code MOR 10.2, Cernet, site coordinates 46°17'30.924"N, 7°19'46.046"E, 1125 masl, 18.03.2020; Figs
The sampling site is situated in a deeply incised section of the Morge, accessible by a logging road. It is regularly subject to active water erosion which destabilizes the stream banks. The stream bed is made up of very large boulders, or even locally stone slabs, as well as sand and gravel on the stream banks (Figs
More than half (51%) of the 302 assessed species of caddisflies are on the Red List of threatened species of Switzerland (
Discovered specimen (last instar larva) of Stactobia eatoniella. The larva and its case are shown in lateral (top), dorsal (bottom left), and ventral (bottom right) view. Figure adapted in Photoshop CS5 from photographs taken with a Canon 65 mm MP-E lens mounted on a Canon EOS 6D camera integrated in an LK lab imaging system (Dun, Inc., Virginia).
We are grateful to the "Service de l’environnement" of the Canton du Valais (SEN) for their trust, and to Marc Bernard for his precious help in the field. We thank Yannick Chittaro (info fauna), Michel Sartori, Jean-Luc Gattolliat, Marion Podolak and Anne Freitag (Museum of Zoology in Lausanne), and Camille Marshall for precious comments on the manuscript. We also thank Wolfram Graf for his constructive and expert review of this manuscript.