Application of pitfall traps for studying the terrestrial mollusk fauna (Mollusca: Gastropoda)

Various methods are employed to survey the terrestrial mollusk fauna. One of the commonly used collection techniques involves pitfall traps, which are often equipped with specialized baits. In this study, we present the results of using pitfall traps without bait to investigate the Gastropoda fauna. The research was conducted between 2022 and 2024, covering a total of 150 pitfall trap lines across eight regions of European Russia. The total processed material comprised 508 specimens representing 22 species. The most abundant mollusks in the traps were slugs from the families Arionidae and Agriolimacidae, accounting for 67% of the collected specimens. Among them, Arion fuscus made up 39%, Arion fasciatus – 9%, Deroceras sp. – 8%, Deroceras agreste – 4%, and Deroceras leave – 3%. Additionally, Fruticicola fruticum, a common inhabitant of moist environments, and the hygrophilous species Pseudotrichia rubiginosa were relatively frequent, constituting 5% of the total sample. All mollusk species collected during the study period are typical for the European part of Russia. The invertebrates captured using pitfall traps can serve as indicators of the investigated habitats in these regions.