Spatial Organisation of an Insect Ensemble in a Mediterranean Ecosystem: the Tenebrionid Beetles (Coleoptera: Tenebrionidae) Inhabiting an Adriatic Coastal Sand Dune Area

We studied the spatial organisation of an ensemble (phylogenetically bounded group of species that use a similar set of resources within a community) of tenebrionid beetles in a Mediterranean coastal sand dune ecosystem in Southern Italy (Molise region). Within a transect from the seashore to the inner dune, we identified four biotopes defined by different vegetation types. We found a community dominated by few sand specialised and r-selected tenebrionid species. Overall tenebrionid abundance was lowest on the upper beach, highest on the embryonic shifting dunes and then from there declined further inland. The embryonic shifting dunes biotope showed the highest diversity and the lowest dominance. This pattern suggests that tenebrionid beetels are able to cope with the challenging salty and xerothermic conditions of the seaward margin. Although some species were too rare to assess their biotope preference, our data support that, at least some, were distributed with different abundance over the four dune biotopes. These differences are likely related to different preferences for different characteristics of substratum and detritus.