Life history traits and resource utilisation in an assemblage of north temperate Aphodius dung beetles (Coleoptera: Scarabaeidae)

To help understand and interpret the structure and function of Aphodius dung beetle assemblages, life history traits and resource utilisation were studied for the ten species comprising the local assemblage of intensively grazed pastures in southern Ireland. Most species were univoltine but one species (A. fimetarius) was at least partly bivoltine. However, temporal overlap in adult flight periods does not necessarily imply overlap in resource use. Three different strategies of ovarian development were distinguished and were related to the preferred oviposition site and successional occurrence of the various species. Evidence suggested that absence of mature eggs in a female's ovaries did not necessarily imply that a female was in a non-reproductive state. Two species (A. prodromus and A. sphacelatus) did not breed in dung; in the laboratory larvae were reared in decaying vegetation. One species (A. erraticus) developed in brood masses beneath the dung pat. Larvae of all the other species developed within the dung pat. There were consistent interspecific differences in the larval development rates, with two species (A. rufipes and A. rufus) overwintering mainly as prepupae and the other species mainly as adults. Previous studies have considered Aphodius assemblages as single guilds but the detailed natural histories of these species may affect guild designation.