Hygropetric and litter-inhabiting spiders (Araneae) from the Abruzzo Apennines (Central Italy)

Abstract

We present the results of a study of spider material extracted by means of Berlese apparatus from wet mosses and by litter sieving in broadleaf woods within several natural reserves of the Abruzzo region (Central Italy). The main aim of the work is to contribute to the knowledge of the spider fauna of the Apen- nines; currently one of the lesser known in Italy. In total, 520 spiders, belonging to 49 species and 14 families were collected. The most abundant and diverse family was Linyphiidae, with 278 individuals belonging to 22 species. Altogether we provide 28 new records for the Abruzzo region, including two species of Theridiidae, twenty of Linyphiidae, four of Hahniidae and two of Thomisidae. We also present additional unpublished records of several rare, litter-inhabiting species collected by litter sieving in the same area. Data on habitat preferences and details on the Italian distribution of the rarest species are presented. Hygropetric habitats become established on rocky or soil surfaces, with thin water films moving down in a mostly laminar flow. This habitat is colonised mainly by bryophytes (mosses and peat-mosses) and often harbours unique assemblages of arthro- pods, characterised by endemic or rare species. Hygropetric communities have received very little attention, both from an ecological and faunistic point of view, especially concerning spiders. We present the results of material sampled within the framework of a comprehensive study program on the Apenninic fauna, in which particular attention was given to hygropetric habitats. The main aims of the present work are to characterise the hygropetric spider assemblages, focusing on both petrimadicolous habitats, develo- ping on rocky surfaces, and limimadicolous ones, developing on the soil surface, and to contribute to the knowledge of the spider fauna of the Apennines; currently one of the lesser known in Italy (PESARINI 1995, ISAIA 2003). We also present additional un- published records of several rare, litter-inhabiting species collected by litter sieving in the same area, including details on their Italian distribution and habitat preference.