Flies of the genus Apocephalus are common parasites of worker ants. Although the mechanisms used by parasitic flies to find their host are not well understood, olfactory cues have been suggested as the mechanism for host location, especially when the host ant is injured. In this study we describe, for the first time, parasitism of Dinoponera gigantea, a monomorphic neotropical ant species, by flies of the genus Apocephalus and test the hypothesis that injured worker ants attract more parasites than uninjured ones.
We also evaluate the attractiveness of haemolynph produced by injury. To test the attractiveness of worker ants to Apocephalus flies, ants were divided into three groups. Group A was composed of injured workers, group B of workers with no injury, and group C of uninjured workers, but with a drop of the haemolynph from the injury of workers. Injured workers suffered more attacks by flies than uninjured ones, but there was no difference between uninjured workers with and without haemolynph on the body. Our data suggest that injury on the worker body of Dinoponera gigantea represents an important attracting stimulus for parasitic Phoridae, as demonstrated for other ponerine ants.