Baits about two meters apart along the boundary zone between native (Solenopsis geminata) and imported (Solenopsis invicta) fire ants in Central Texas. The bait on the left attracted S. invicta workers that are retrieving food. Simultaneously, S. geminata workers on the nearby bait (right) are not retrieving food, but rather posturing in response to two native female phorid flies (Pseudacteon crawfordi) (arrows) seeking to oviposit. (Photos: L.E. Gilbert)