Deaf male mosquitoes are unable to reproduce, according to new research by scientists. Depriving the insects of their sense of hearing drastically changed their mating behavior and caused the mosquitoes to completely lose interest in the opposite sex. According to the authors, the surprising discovery may prove helpful in the fight against species that spread deadly diseases.
The results of an experiment conducted at the University of California amazed scientists. A team led by Craig Montell used DNA modification techniques to create deaf mosquitoes. This brought about a drastic change in their sexual behavior.
“You can leave them with the females for a few days and they won't mate,” Montell said.
Experts say that the conclusions from the study not only show how important the sense of hearing is in these insects, but also may be valuable in the fight against mosquito species that transmit diseases that are fatal to humans. Details were published in the “Proceedings of the National Academy of Sciences”.
The most developed hearing among insects
Scientists have revealed that male mosquitoes have the most auditory neurons among insects. Although females have half as many hearing aids, their hearing is still among the best. The neurons are located at the base of the antennae in a structure called Johnson's organ.
In the study, experts focused on a specific sensory channel called TRPVa and its corresponding gene, trpVa, which is the equivalent in mosquitoes of the channel required for hearing in fruit flies.
– Single gene missing trpVa caused this profound effect on the behavior of mosquitoes during mating – explained Dhananjay Thakur, working at the Department of Molecular, Cellular and Developmental Biology.
The flapping of wings
Experts noted that the male mosquito of the species Aedes aegypti they respond to the frequency of the sound made by the female's flapping wings, which is approximately 500 Hz. When they hear this, they fly away, buzzing at around 800 Hz. Males also rapidly modulate this frequency when females are nearby. In this way, both insects send signals to each other, which end in copulation.
After removing the gene trpVa mosquitoes lost their sense of hearing, which drastically changed their behavior. When the authors placed deaf males in chambers with females… nothing happened
“If they can't hear the female's wingbeat, they're not interested,” Montell emphasized.
According to scientists, hearing is not only necessary for males to copulate, but also seems to be sufficient to arouse their desire. Interestingly, the impact of hearing loss on behavior varies depending on gender.
“The impact on females is minimal, but on males it is absolute,” Montell said, adding that his team would like to investigate this issue in the future.
Aedes aegyptiShutterstock
Shocking conclusions that may prove helpful
According to the authors, the research results are “shocking”.
– For most organisms, mating behavior depends on a combination of several sensory signals – emphasized one of the students conducting the experiment.
The researchers believe that the conclusions about the role of sound in mating and the function that TRPVa plays in hearing can be generalized to other mosquito species.
This may mean a new method of combating insect species that transmit deadly diseases. Currently, one of the activities undertaken for this purpose is to reduce the population of dangerous insects by producing colonies of sterile individuals.
About 700,000 people die annually from mosquito-borne diseases (including yellow fever and dengue).
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