OFF with their heads! In the competition for fire ant hosts, is Pseudacteon curvatus delivering the knock-out punch?

Pseudacteon spp. flies (Diptera: Phoridae) are one of many biological controls of fire ants in their native South America, and were first released in Alabama in 1998. Three species, P. curvatus, P. litoralis, and P. tricuspis were the focus of this study. Diurnal flight patterns and seasonal abundance of these species were monitored in Alabama from August through October of 2010, and again from June 2012 through June 2013. These data were compared to data collected in 2002.

In 2002, the species were not in competition for resources and were found in large numbers in their respective locations. However, the 2010, 2012-2013 data were collected with the species coexisting in the same geographical locations. The data shows that there has been a dramatic shift in P. tricuspis numbers while in competition with P. curvatus for resources, making P. curvatus the predominant fly species. There has also been a major shift in diurnal activity of P. curvatus when all three species are in competition for resources.