Effects of the attractiveness for dung beetles of dung pat origin and size along a climatic gradient

Dung beetle (Coleoptera: Geotrupidae, Scarabaeidae) assemblages were monitored by dung-baited pitfall trapping at three sites distributed along a bioclimatic gradient from semiarid to mesic temperate. For each type of dung, both small and large sized baits were used. Under semiarid conditions (Morocco), three dung beetle assemblages were distinguished: small bait assemblages in any dung; large cattle bait assemblages; large sheep bait assemblages. Under more temperate conditions (southern France and the Alps), only large and small bait assemblages were observed, whatever the origin of the dung. Large baits attracted significantly more species and more beetles than did small baits, and very few species were attracted significantly more by either sheep or goat baits than by cattle baits. A significant, positive correlation between dung beetle size and dung pat size was observed in Morocco where the large species are predominant, whereas a negative relationship was observed in southern France where the small species are predominant. Cattle pats were more attractive for beetles under xeric and Mediterranean conditions (Morocco and southern France) that under cold temperate conditions (Alps).