Relationships between an introduced and two native dung beetle species (Coleoptera: Scarabaeidae) in Georgia

Field collections, and laboratory observations and experiments, were conducted in Tift County, GA, to determine possible interactions among the three most abundant species of nocturnal scarab dung beetles. Light-trap data indicated that Copris minutus occurred primarily in the winter and spring, Ateuchus histeroides in the spring and summer, and Onthophagus gazella in the summer and fall. One of the species, O. gazella, is a foreign introduction, and comparative laboratory food procurement experiments revealed the superior ability of this species to obtain and remove dung from the soil surface. A confrontation experiment also demonstrated the behavioral dominance of O. gazella. A food-choice experiment indicated a more restricted diet for O. gazella than for the other two species. Implications for the future prospects of the two native species are discussed.