Resource Partitioning and Interspecific Interactions among Riparian Bembidion species (Coleoptera: Carabidae)
The resource dimensions macro-micro-habitat, time (life cycle) and food selection were studied for riparian Bembidion species in N' Norway. The mean spatial overlap of habitats (H-O) between species (adult beetles) was 0.11 (Piankas niche-overlap formula). In the few cases where H-O was high, there were differences in size and/or cycle. Larger species are able to take larger prey species than smaller ones, and size differences of species probably imply differences in food selection. - Despite that the larvae are extremely aggressive, coexistence of species of different sizes is suggested, because size differences probably lead to exploitation of different resources (food, space). Although the spatial segregation of the species largely is due to differences in requirements for and tolerances of abiotic factors, there are some indications of negative interactions between species. The spatial H-O of generalist species and specialist species is low, despite the fact that generalist species are able to exist successfully in a number of different habitats when specialist species are absent there.