Romantic Mosquitoes Compose Love Songs

On a hot summer night, you hear the familiar and annoying sound of a mosquito that flies somewhere in the darkness. However, this dreadful buzz can actually be a song of love between two mosquitoes. Researchers at Cornell University have shown that male and female mosquitoes of the species Aedes aegypti continuously alter their wing beat frequencies to match each other’s during mating behavior. They culminate at a specific frequency, achieving a romantic duet.

Previous research suggested that male mosquitoes couldn’t hear above 800 Hz. Females were also considered to be entirely deaf. However, this experiment revolutionized our knowledge of both their mating interactions and sound perception. Researchers tethered flying mosquitoes and moved one partner past the other, who was stationary. Recordings from a particle velocity microphone revealed that both sexes responded to each other by synchronizing the frequencies of their wing beats. They ultimately culminated at 1200-1300 Hz, which is well above the fundamental wing beat frequency of 600 Hz for males and 400 Hz for females. It also exceeded the established hearing range for both sexes. When the mosquitoes were deafened, no matching occurred. This provided evidence for the acoustic transmission of information. They further tested this hypothesis by removing the flying partner. Signals were electrically generated through a probe that imitated a natural flight pattern. The mosquitoes still coordinated their frequencies, showing that only sound is necessary.

Confused by previous assumptions about the hearing range of mosquitoes, researchers also inserted electrodes into the Johnston’s organ to once again test perception. They utilized a different filter than in previous experiments and found that both males and females respond to frequencies as high as 2000 Hz.

Another interesting development involved differences between mated and unmated females. A greater number of unmated females responded to playback experiments involving a 1400 Hz pure tone than did mated females to a full male song. Consequently, the acquisition of a mate leads female mosquitoes to be less responsive to other males.

Knowledge of this romantic courtship can help control mosquito populations. One method is to release sterile males into a population, but their diminished fitness may be shown in their ability to match frequencies of females. They are therefore unattractive, hampering the effectiveness of population control. This research can later provide methods of enhancing the desirability of sterile males and thus increase the efficiency of population control. Summer nights may even be a little less noisy.

To read the popular article, click here. To read the research article behind it, click here.

Posted by Katie Kalutkiewicz (Group A)