Species richness, abundance and distribution of myrmecophilous beetles in nests of Formica aquilonia ants

Some ecological theories predict a positive relationship between species richness and resource size, resource abundance, or resource concentration. In this study, we tested these three hypotheses with myrmecophilous beetles, which use ant nests as their hosts. The resource concentration hypothesis predicts that patches with a high density of a resource support high richness of species dependent on that specific resource. The resource abundance hypothesis predicts that the hosts offering more resources support more species. The resource size hypothesis predicts that larger hosts support more species than smaller hosts. We collected beetles from nests of the nest building wood ant Formica aquilonia. In 49 F. aquilonia nests, we observed 965 individual beetles and 16 species of myrmecophilous beetle. Both the nearest neighbour distance and the volume of ant nests influenced species richness and beetle number. The beetle species utilising several hosts were more widespread and more abundant than the specialist beetle species. Thus, our findings support the resource concentration, resource size and resource abundance hypotheses.