BEHAVIOR AND HOST LOCATION CUES OF APOCEPHALUS-PARAPONERAE (DIPTERA, PHORIDAE), A PARASITOID OF THE GIANT TROPICAL ANT, PARAPONERA-CLAVATA (HYMENOPTERA, FORMICIDAE)

Apocephalus paraponerae (Diptera: Phoridae) is a parasitoid of injured workers of Paraponera clavata. Both male and female flies are attracted to prospective hosts, the males to feed and the females to feed and oviposit. Flies were attracted to extracts of crushed workers, the first definitive evidence for an olfactory mode of attraction in parasitic phorid flies. Increasing the number of injured workers increased the number of parasitoids attracted. A. paraponerae showed a strong attraction to P. clavata workers in comparison to other ant species, suggesting host specificity. A continuous supply of injured ants is furnished by frequent inter-colony aggressive encounters in P. clavata, which can yield many maimed workers. High local populations of A. paraponerae relative to other ant parasitoids is probably due to multiple parasitism of host workers and ready host availability. We suggest that phorid parasites that use olfactory cues to locate hosts may play a role in the evolution and maintenance of pheromone diversity in ants.