Dispersal patterns of a saproxylic beetle, Osmoderma eremita, in Mediterranean woodlands

* Dispersal patterns of a beetle inhabiting tree hollows, Osmoderma eremita (Scopoli, 1763) (Coleoptera: Cetoniidae), were studied in a cork oak (Quercus suber) woodland in central Italy, the southernmost part of its distribution range. During 2 years, we used radio telemetry to monitor dispersal of 39 free-ranging individuals (16 males, 23 females). * Telemetered beetles spent their lifetime not only inside hollow trees but also in other habitats, such as above or under the ground surface. * Beetles were more active at the beginning of the season. Eighty-one per cent of the males and 69% of the females conducted dispersals during their lifetime. * The dispersal distance over individuals' lifetime did not differ between sexes. The longest dispersal was conducted by a female that moved 1504 m. Thirty-nine per cent of dispersing individuals reached distances farther than 250 m. Both dispersal rate and range are higher than what has been found in Northern Europe. * The population size per tree is low, most of the adults leave their natal tree, and a high predation rate (at least 28%) was observed among dispersing beetles. Therefore, to balance the local extinction risk from single trees, a high density of hollow trees is probably required. It is desirable that suitable trees are concentrated at a spatial scale of a few hundred metres.