The Tenebrionidae (Coleoptera) of a Tyrrhenian coastal area: diversity and zoogeographical composition

Abstract

Biogeographia vol. XXIII - 2002 (Pubblicato il 1° ottobre 2002) Biogeografia degli ambienti costieri The Tenebrionidae (Coleoptera) of a Tyrrhenian coastal area: diversity and zoogeographical composition SIMONE FATTORINI Dzpaifimento di Biologizz Animzzlc e a’e[[’U0mo (Zoologia), Uni:/erritfz di Roma qLa Szzpz'mzzz”, Vizzle de[l’Uniz/em'tz‘z 32, [—00]85 Roma (Italy) Key words: tenebrionid beetles, biogeography, ecology, Mediterranean, Central Italy, Castelfusano SUMMARY The family Tenebrionidae represents an important faunal component of Mediterranean coastal ecosystems. Until a recent fire Ouly 2000), which unfortunately destroyed large sectors of an introduced pine forest, the protected area of Castelfusano (about 1000 hectares, near Rome, Latium) was a Tyrrhenian coastal site where psammophilous vegetation, maquis, oak forests, hygrophilous forests, and an introduced pine forest occurred. The aim of this work was: (1) to provide a flunal inventory of the tenebrionids of Castelfusano before fire, and (2) to analyse this fauna from both an ecological and a zoogeographical point of view. A total of 29 tenebrionid species, belonging to three main ecological guilds, were recorded: (1) sand dwelling species inhabiting the beach—dune system; (2) geophilous species of maquis and open areas; (3) xylophilous species, especially associated with the pine forest. Based on their general distribution, the tenebrionid beetles ofCastelh1sano can be grouped into eight chorological categories. As to the environmental Factors responsible for this chorological spectrum, a relationship can be observed between species ranges and ecological preferences. In accordance with the Tyrrhenian location of the study area, most of the species appear to be more or less widely distributed in the Mediterranean basin, with a high proportion of West Mediterranean and S—European elements. Species with such types of distribution are also typically thermophilic species. Therefore, the climate of the study area, favouring species with thermophilic preferences, can be responsible for a high incidence of species with such ranges. Species with more northern distributions are relatively scarce, including some euryoecious or xylophilous elements. The presence of species with such ranges can be related to the occurrence of patches of mesophilic vegetation in the study area. Most probably, such species largely colonised Italian coastal areas during Pleistocene glaciations. As the climate became drier and warmer, d‘l€SE species were forced to assume more northern distributions. However, isolated populations were able to survive also in areas like Castelfusano, where favourable habitats persisted. Therefore, these relict populations are a result of vicariance events determined by the fragmentation of Pleistocene mesophilic habitats. Most of the species recorded for the forest vegetation of Castelfusano also occurs in the adjacent Presidential Estate of Castelporziano, a large and wellfipreserved area. Therefore, Castelporziano will operate as a source area for the renebrionid colonisation of the Castelfusano area destroyed by fires if favourable habitats will be restored. INTRODUCTION The family Tenebrionidae represents a conspicuous faunal component of arid and semi—arid environments, and the importance of these beetles in Mediterranean