Temporal patterns of parasitoid fly ( Ormia ochracea) attraction to field cricket song ( Gryllus integer)

Female flies, Ormia ochracea (Diptera, Tachinidae), orient to the calling song of the field cricket Gryllus integer (Orthoptera, Gryllidae) and deposit larvae that burrow into and consume the cricket host. Selection pressure from O. ochracea has probably been important in the evolution of male cricket songs and mating behaviour in G. integer and other cricket species. Tape-recorded G. integer calling song was broadcast to study the temporal rate of attraction of O. ochracea. Flies became phonotactic to cricket song approximately at sunset, and the highest level of attraction was observed in the following hours of the evening. Fly phonotaxis decreased in the hours immediately preceding sunrise and no flies were attracted during daylight hours. More male G. integer call at sunrise and in the preceding hours than earlier in the evening, perhaps in response to the lower probability of attracting O. ochracea.