DIVERSITY IN WESTERN MEDITERRANEAN ISLETS - EFFECTS OF RAT PRESENCE ON A BEETLE GUILD

Data collected on 51 islets of the Balearic islands (Mediterranean Sea ) support that the presence of Rattus rattus produces a decrease in th e number of endemic tenebrionid beetles. Moreover, species-specific pa tterns have been detected. Five endemic beetles show a significantly s maller number of presences within rat infested islets than expected. I n contrast, only two beetle species are favoured by the presence of ra ts, both of which are non-endemic.