Fight against dengue fever: Deaf mosquitoes stop having sex

Scientists believe they have found a novel way to combat diseases spread by mosquitoes, such as dengue fever, yellow fever and Zika, by deafening male insects so they struggle to mate and reproduce.

Mosquitoes have sex while flying through the air, and males rely on their hearing to pursue a female, based on her attractive wingbeats.

Researchers performed an experiment by modifying a genetic pathway that male mosquitoes use for hearing. Result: they had no physical contact with the females, even after three days spent in the same cage.

Female mosquitoes are the ones that spread diseases to humans, and so trying to prevent them from having babies would help reduce the overall number of mosquitoes.

The team from the University of California, Irvine, studied Aedes aegypti mosquitoes, which spread viruses to about 400 million people a year.

They closely observed the insects’ aerial mating habits – which can last from a few seconds to just under a minute – and then found a way to disrupt them through genetics.

They targeted a protein called trpVa that appears to be essential for hearing.

In the mutant mosquitoes, neurons normally involved in sound detection did not respond to flight sounds or wing beats from potential mates.

The seductive noise fell on deaf ears.

In contrast, wild (non-mutant) males copulated quickly, several times, and impregnated almost all the females in their cage.

Researchers from the University of California, Santa Barbara, who published their work in the journal PNAS, said the effect of knocking out the gene was “absolute”, since mating by deaf males was entirely eliminated. eliminated.

Dr Joerg Albert, from the University of Oldenburg in Germany, is an expert on mosquito mating and I asked him what he thought of this research.

He said attacking the sense of sound was a promising avenue for mosquito control, but it needed to be studied and managed.

“The study provides a first direct molecular test, which suggests that hearing is not only important for mosquito reproduction, but that it is essential.

“Without the ability of males to hear – and hunt acoustically – female mosquitoes could disappear.

Another method being explored is releasing sterile males into areas where there are pockets of mosquito-spread disease, he added.

Although mosquitoes can carry disease, they are an important link in the food chain – they feed fish, birds, bats and frogs, for example – and some are important pollinators.