Organic farms conserve a dung beetle species capable of disrupting fly vectors of foodborne pathogens

We examined the possible implications for food safety of interactions between O. taurus and a common fly species on the farms, Calliphora vomitora, in microcosms containing pig (Sus scrofa) feces inoculated with human pathogenic E. coli O157:H7 and placed near broccoli (Brassica oleracea) plants. In the absence of dung beetles, Calliphora vomitora readily acquired the bacteria and transmitted them to broccoli foliage. In the presence of the dung beetle O. taurus, however, E. coli in the soil and fly survivorship were reduced, and the pathogen was rarely recovered from foliage. Altogether, our results suggest the potential for O. taurus to both directly suppress enteric pathogens in vertebrate feces and to indirectly reduce the spread of these bacteria by co-occurring flies. The beneficial beetle O. taurus was common only on organic farms, suggesting these benefits of beetle-fly interference for food safety could be more likely under this farming regime. Future research that investigates interactions between the many other common dung beetle and fly species on these farms would help fully delineate any net benefit of these species-rich coprophage communities, and the farming systems that shape them, for food safety.Graphical abstract

Source: Biological Control - July 4, 2019 Category: Biology Source Type: research