The Old World blow fly, Chrysomya rufifacies, is one of four Chrysomya spp. that have recently invaded the New World, and the first to enter the United States. These flies are pests in their home range and pose a threat to U.S. agriculture and human health. Displacement of native blow flies by these introduced species has been reported, but no mechanism of displacement has been demonstrated. The biology of blow flies suggests that important population interactions occur during the larval stage. These experiments will measure the impact of C. rufifacies on Cochliomyia macellaria, an native fly whose ecological habits most resemble those of C. rufifacies. The time at which females arrive at carrion and oviposit, along with the time larvae leave carrion, will be used to determine the temporal overlap of fly species in carrion of 3 sizes and in 3 types of habitat. Densities of these two species in carrion will be manipulated to determine the interaction between larvae of C. rufifacies and larvae of C. macellaria. Preliminary observations indicate that the red imported fire ant, an exotic insect that has recently invaded the study area may have become the dominant predator in the carrion community. Exclusion experiments will define the role of this ant in carrion, and in particular, its effect on the interaction of the two fly species.
