Blow flies are primary colonizers of carrion and thus interact with many organisms in a highly competitive environment. Due to the large variety of insects that utilize carrion resources, predators are also often in high abundance, placing selective pressures on necrophagous insects to develop antipredator defenses. Blow fly antipredator defenses are largely studied for larval stages as they are heavily predated on when feeding on a carcass. Consequently, our understanding of adult defenses are limited. In this paper, a potential antipredator defense against the red imported fire ant (Solenopsis invicta (Buren) (Hymenoptera: Formicidae)), an invasive species to the Southeastern United States that is known to compete with and prey on necrophagous insects, was observed. During the summer and winter of 2019 in central Texas, USA adult blow flies (Lucilia spp. and Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae)) were observed attempting to colonize chick (Gallus gallus domesticus) and rat (Rattus norvegicus) carcasses already colonized by fire ants. Ovipositing flies approached by fire ants buzzed their wings, seemingly to repel fire ants as they did not buzz their wings for flight unless engagement by fire ants was persistent or severe enough to drive the fly from the carcass. Wing buzzing is a common phenomenon across several insect orders and is thought to be used in part for defensive purposes. The primary non-flight related behavior regarding wing movements in blow flies is a mating display involving wing fanning in Lucilia sericata (Meigen) (Diptera: Calliphoridae). However, this behavior is generally slower and more rhythmic than the aggressive “buzzing” flies exhibited against fire ants. Wing buzzing as an antipredator defense has been shown to increase survivorship in other insects, though wing damage may occur and wing movements cost energy. Further investigation of adult blow fly interactions with native and non-native predators will increase our understanding of wing buzzing as a potential antipredator defense in blow flies, and their consequences in applied fields.
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