Mosquito sound communication: are male swarms loud enough to attract females?

Abstract

SUMMARYThe high-pitched whine of mosquitoes in flight is produced by their wingbeats, and is heard by conspecifics, who have unsurpassed sound sensitivity among arthropods. We investigated whether female mosquitoes might use the sound of a mating swarm at long-range (several meters) to identify species-specific cues. In the laboratory we exposed free-flying An. coluzzii females to pre-recorded male An. coluzzii and An. gambiae s.s. swarms to assess female response to male flight sounds over a range of ecologically-relevant sound-levels, based on our reference recording (70-male swarm producing 20 dB SPL 0.9m away). Sound-levels tested were related to equivalent distances between the female and the male swarm for a given number of males, enabling us to infer distances over which females can hear large male swarms. Females did not respond to swarm sounds at 36±3 dB, but their flight speed increased significantly at 48±3 dB, equivalent to a distance of 0.6±0.2 m from a point-source swarm-sound produced by 1,000 males. However, this distance is less than the 1,000-male swarm radius. We show that even for the loudest swarms of 10,000 males, a female will hear an individual male at the edge of the swarm sooner or more loudly than the swarm as a whole, due to the exponential increase of sound at close-range. Therefore, females highly unlikely cannot use swarm sound to locate swarms at long-range. We conclude that mosquito acoustic communication is restricted to close-range dyad interactions.

Behavioural analysis of swarming mosquitoes reveals higher hearing sensitivity than previously measured with electrophysiology methods

“…4 B for example and statistics of wingbeat and flight dynamic characteristics before, during and after exposure to the loudest 1-female sound-stimuli (44±2 dB SVL)). The two components were synchronized using the same techniques as in a previously published study (22). (3…”