Targeting mosquito hearing to reduce disease transmission

Researchers have identified the molecular pathway that allows male mosquitoes to hear females, a factor that’s crucial to their reproduction. The discovery could lead to the development of insecticides that exploit this pathway as a novel way of controlling mosquito populations, thereby reducing the transmission of diseases.

Tackling a problem like diseases spread by insects sometimes requires thinking outside of the box. That’s just what researchers from University College London did to come up with a potential way of reducing the spread of mosquito-borne diseases like malaria, dengue and yellow fever.

The male mosquitoes’ ability to hear the faint buzz of flying female mosquitoes hidden amongst large, noisy swarms is crucial to their ability to reproduce. But the mechanism by which they do this has been poorly understood until now.

Yes, mosquitoes have ears. While they’re not like vertebrate ears, which detect changes in pressure waves emitted by a sound source, mosquitoes use their antennae as movement receptors that respond to air particles oscillating within the insects’ surroundings.

The researchers focused on a particular molecule, octopamine, which is linked to the male mosquitoes’ hearing abilities. Examining gene expression in the mosquito ear, they found that a mosquito swarm causes the octopamine receptor in the male mosquito’s ear to peak specifically.

They observed that octopamine affects hearing in a couple of ways: it modulates the tuning and stiffness of the sound receiver and controls other mechanical changes that boost the males’ ability to detect females. While octopamine affected female hearing, it did so to a lesser degree than in males. And they found that injecting octopamine into mutated male mosquitoes did not produce the same auditory-enhancing effects.

The researchers believe their findings have obvious advantages for controlling mosquito populations.

“Octopamine receptors are of particular interest as they are highly suitable for insecticide development,” said Marta Andrés, a corresponding author of the study. “We plan to use these findings to develop novel molecules to develop mating disruptors for malaria mosquitoes. Because mosquito hearing is required for mosquito mating, it can be targeted to disrupt mosquito reproduction. And increased knowledge of mosquito auditory neurosciences could lead to the development of mosquito mating disruptors for mosquito control.”

The researchers say their study will lead to further research into the mechanisms underpinning mosquito hearing and how it can be exploited.

“The molecular and mechanistic complexity of mosquito hearing is truly remarkable,” said co-corresponding author Joerg Albert. “With the identification of an octopamine pathway, we are just beginning to scratch the outer surface of the tip of an iceberg. Future studies will, without doubt, deliver deeper insights into how mosquito hearing works and also provide us with novel opportunities to control mosquito populations and reduce human disease.”

The study was published in the journal Nature Communications.

Source: University College London

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