Macroecology of Dung Beetles in Italy

Simple Summary Dung beetle communities include three groups of insects: the true dung beetles (scarabaeines), the small dung beetles (aphodiines), and the earth-boring dung beetles (geotrupids). The Italian dung beetle fauna is one of the richest in Europe due to the position of the Italian peninsula in the middle of the Mediterranean global hotspot of biodiversity. Dung beetle faunas in the Italian peninsula appear to be richer than that of Sardinia, which has a distinctly impoverished fauna due to its strong isolation from the mainland. Dung beetle species richness varies along the Italian peninsula in response to climatic factors. Aphodiines (that need to use the dung before it dries) are mainly associated with humid and cold climates and do not show a latitudinal pattern, while scarabaeines (which can cope with dry conditions) increase their diversity southward. Dung beetle species composition in Italian regions reflects both random processes of dispersal (possibly favored by human influences due to millennia of grazing activities) and the role of southern areas as refugia during Pleistocene glacials.Abstract The Italian fauna includes about 170 species/subspecies of dung beetles, being one of the richest in Europe. We used data on dung beetle distribution in the Italian regions to investigate some macroecological patterns. Specifically, we tested if species richness decreased southward (peninsula effect) or northward (latitudinal gradient). We also considered the effects of area (i.e., the species-area relationship), topographic complexity, and climate in explaining dung beetle richness. Finally, we used multivariate techniques to identify biotic relationships between regions. We found no support for the peninsula effect, whereas scarabaeines followed a latitudinal gradient, thus supporting a possible role of southern areas as Pleistocene refuges for this group of mainly thermophilic beetles. By contrast, aphodiines were more associated with cold and humid climates and do not show a distinct latitudinal pattern. In general, species richness was influenced by area, with the Sardinian fauna being however strongly impoverished because of its isolation. Faunal patterns for mainland regions reflect the influence of current ecological settings and historical factors (Pleistocene glaciations) in determining species distributions.