Contribution à l’inventaire de quelques groupes d’Arthropodes de l’île de Cavallo (archipel des Lavezzi, Corse) : insectes (Coléoptères, Hétéroptères aquatiques) et arachnides (Araneae)
Résumé
Four days of naturalistic survey were performed in 2013 and 2014 on Cavallo Island. They yielded a provisional inventory concerning several groups of Arthropods, in particular Coleoptera, aquatic Heteroptera, and spiders. This is the first significant contribution to the knowledge of this poorly known island. Fifteen Coleopteran species, no Heteroptera, no spiders, were reported from Cavallo up to now. Ninety-one Coleopteran species, 6 aquatic Heteropteran and 28 spiders are currently listed in the present work. Concerning the Coleoptera, we compared these results with fossil data yielded by a palaeoentomological analysis spanning the last 7000 years, recently performed on the Grecu pond, which enabled to identify 133 fossil taxa of Coleoptera. Several species reported in this work were not found again during our recent surveys, maybe in response to environmental perturbations induced by both a Holocene sea level rise (shrinkage of Grecu pond and salinity increase), and a strong impact of human activities on the
natural environment from the Neolithic period onwards (vegetation clearance, pastoralism, and more recently urbanization of a notable part of the island). Significant results include the discovery of a spider new for the French fauna, Argiope trifasciata. Several Coleoptera are interesting from a biogeographical point of view,
this is the case of Percus strictus mucronatus, an endemic ground beetle subspecies from Cavallo, and Amaurorhinus sardous, an endemic weevil from Corsica and Sardinia, the northern limit of its distributional range being the archipelago of Bouches-de-Bonifacio.