Onthophagus nuchicornis (Linnaeus), an accidentally introduced dung beetle, is the only scarabaeine species encountered commonly in cattle dung in British Columbia. Its dung burial efficiency and its potential for inhibiting development of coprophagous fly larvae were measured in greenhouse experiments.
The beetles buried dung most efficiently when they were present in the ratio of one pair per 40–50 g of feces. Higher or lower rates of infestation resulted in reduced burial Survival of fly larvae was inversely related to the numbers of brood balls constructed by the beetles, and hence to the amount of dung buried. Beetle activity in the field probably has little harmful effect on the dung-breeding horn fly as the beetles cease burial activity before midsummer, when horn flies reach their greatest numbers, and as they do not bury significant amounts of dung in pastures.
The desirability and possibility of introducing exotic dung beetles into British Columbia for fly control is discussed.