P a r a s i t i c   F l y

There are many species of parasitic flies and wasps in the rain forest that can only survive by reproducing on another specific kind of insect host. By so doing they help to control population explosions of such insects. This fly, the leaf-cutter ant parasitic fly, lays its eggs only on the backs of leaf-cutter ants.

Usually, the large worker leaf-cutter ants that cut and carry the leaves back to the nest are protected both by soldier leaf-cutters with huge jaws and by smaller worker leaf-cutters that remain close by or "hitchhike" on the piece of leaf. These smaller workers chase away potential predators like the fly. The fly circles the worker ants, attempting to get close enough to deposit an egg and fly away; the smaller worker ants prevent it from getting too close. However, if the large worker leaf-cutter is left unguarded, it can have an egg deposited on its back by the fly. The fly larva that hatches from the egg burrows into the ant, eventually killing it. The larva finally develops into an adult fly, having lived off the body of the ant.

Both the ant and the fly, in turn, can be eaten by other ants or by larger insect-eating animals, such as antbirds or anteaters.