Mosquito Egg Raft Distribution Is Affected by Semiochemicals: Indication of Interspecific Competition.

Numerous species of animals alter their behavior in response to increasing competition. To do so, they must possess the ability to detect the presence and density of interspecific competitors. We studied the role of semiochemicals released by increasing densities of larval Macquart on female oviposition habitat selection in two field experiments. Similarly to larvae, subordinate Edwards are periphyton grazers who dwell in rain-filled pools in the Mediterranean region. We show that females oviposited significantly less in mesocosm pools that were treated with crowding signals originating from larvae. In the second experiment, we placed a similar number of larvae directly inside the 50 L mesocosms. These low-density mesocosms did not affect oviposition but were attractive to conspecific oviposition. These results increase our understanding of the female ability to detect species-specific signals, indicating increased larval competition.