Researchers have discovered a unique way to prevent the spread of diseases like dengue, Zika and yellow fever by making mosquitoes deaf.

The primary carriers of these viruses are Aedes aegypti mosquitoes, which spread the disease through their bites. According to a recent study, disabling the hearing ability of male mosquitoes hinders their ability to mate, potentially slowing the spread of these vector-borne diseases.

This approach highlights the essential role of hearing in mosquito mating. Researchers in the laboratory of Professor Craig Montell found that when male mosquitoes lose their hearing, they show no interest in mating with females. Typically, mating occurs in mid-air, triggered by the distinctive sound of the female’s wing beats, which the males can recognize as a signal to pursue them.

By disrupting this auditory signal, scientists hope to reduce mosquito populations and curb the transmission of these dangerous diseases.

“The absence of a single gene, TRPVA, had such a profound effect on the mating behavior of mosquitoes,” said co-lead author Dhananjay Thakur, a postdoctoral scholar in the Department of Molecular, Cellular and Developmental Biology.

Female mosquitoes flap their wings at approximately 500 Hz, which attracts nearby males. When males hear this sound, they begin to buzz at a high pitch around 800 Hz and quickly adjust their frequency.

This leads to a brief encounter in the air, after which they part ways. While males are constantly looking for new mates, a female usually does not mate again after a successful encounter.

The team at the University of California, Santa Barbara used CRISPR-Cas9 to knock out the gene that codes for TRPVA in Aedes aegypti mosquitoes. The resulting animals showed no response to the sound.

In fact, they found that the sound did not evoke any electrical activity from neurons in Johnston’s organ. The insects were literally deaf.

Sterile insect technology (SIT) is a promising method of controlling insect vectors by releasing sterile males to mate with females, preventing them from reproducing.

This method has proven effective for agricultural pests such as the California medfly, which was a major problem 30 years before SIT helped control it.

However, the success of SIT on Aedes aegypti mosquitoes is limited because sterile males must reach females before natural males can.

Montell’s lab is now exploring ways to make sterile males more competitive, possibly by targeting mosquitoes’ hearing to increase the impact of SIT on mosquito populations.