Predatory Behavior of Scatophaga stercoraria (Diptera: Anthomyiidae) in California1

Abstract

The yellow dung fly Scatophaga stercoraria (L.) has bright golden males which form conspicuous mating aggregations on the fresh dung of many wild and domestic mammals. The females lay eggs on this dung while their mates protect them from unpaired males (Foster 1967), and the larvae feed on the dung and pupate in its crust or in the soil beneath. Adults are always most abundant and sexually active in the cool spring and fall of temperate climates throughout the world, but the extent of the decline between these population peaks varies with the severity of summer and winter (Foster 1967[3][1]). The numerous published records suggest that Scatophaga is an indiscriminate predator of adult Diptera, killing everything from simuliids to large calliphorids, and also occasionally Homoptera, Psocoptera, and Hymenoptera (Hobby 1931a). Nevertheless, Scatophaga's efficacy as a predator of coprophilic pest flies (e.g. house flies, Musca domesticae L.; blow flies) is disputed, since the usual prey under natural conditions are not fully known, and there is disagreement about the habitat where predation usually occurs. Also, there remains the peculiar observation that Scatophaga predation ceases with the attainment of sexual maturity, so the predatory potential is possibly quite small. [1]: #fn-2