Resource Utilization and Local Coexistence in a Guild of Scarabaeid Dung Beetles (Aphodius spp.)

Abstract

Resource partitioning in a guild of 13 Aphodius species (adults) from cattle dung was studied along two dimensions in time season and age of dung pats and two dimensions in space distribution of beetles among pats and microdistribution within pats. Moreover, total respiration of the guild in relation to season was roughly estimated. Most data were from one site in northern Zealand, Denmark. The energy requirements of this coprophagous guild varied widely through the season. Even at the time of maximum activity, the beetles assimilated only about 0.2% of the energy in a dung pat; hence there is no evidence of competition for food at normal population densities. Neither did other results indicate within-guild competition, past or present. Features like (1) the contagious distribution of beetles on evenly spaced, identical pats, (2) the positive association between species, and (3) habitat specializations within pats may have evolved as adaptations facilitating intraspecific contacts in populations which are often sparse in relation to chances of mating.