Scientist believes a bee-safe insecticide could help hinder dangerous mosquitoes

Bugs emerging earlier in spring, new study finds CTV Science and Technology Specialist Dan Riskin breaks down a new study on how climate change has bugs coming out earlier in the spring.

A genetic discovery about mosquitoes could help scientists prevent the pesky – and sometimes dangerous – insects from ever reaching reproductive maturity, a new study suggests.

When studying fruit flies in 2018, University of California, Riverside entomologist Naoki Yamanaka said he discovered a transporter protein that carries an important hormone called ecdysone through the body of the small insect. Known as the “molting hormone,” Yamanaka said ecdysone is present in every insect species and plays a role in the development from egg to an adult capable of reproduction. In fruit flies, for example, there are four different transporter proteins that carry this hormone.

Yamanaka began testing other insects for these transporter proteins, and all of the species he tested had these transporters. But in this new study, Yamanaka said he found that mosquitoes – and more specifically , known for carrying viruses such as Zika and yellow fever – lacked one of these crucial transporters.

“This primary one is somehow, mysteriously, missing in mosquitoes,” Yamanaka said in a press release on Tuesday.

According to Yamanaka, this discovery could open the door to turn this species of mosquito into “Peter Pans” incapable of ever reaching reproductive maturity, and thus limiting its ability to repopulate. Yamanaka published his findings in Proceedings of the National Academy of Sciences on Monday.

“We can develop chemicals to block the functions of these ecdysone transporters but do not affect the original transporter that is so key for other insects,” Yamanaka said.

This means that an insecticide could be created that specifically targets this kind of mosquito but would not negatively affect other important insect populations – such as bees or other pollinators – who have an extra transporter that would not be impacted, allowing these helpful bugs to continue to mature.

“The chances for off-target effects would be low,” Yamanaka said.

Funded by the U.S. National Institutes of Health, Yamanaka is now studying which chemicals could block these transporters in mosquitoes and is continuing his research into ecdysone hormones in other species.

Mosquito population control methods have long been sought after by the scientific community. One method that is already in use is releasing sterile male mosquitoes into the wild, which eliminates the need for insecticides that could be dangerous to other insect species. But Yamanaka said it is important to find other methods of population control that could work in various environments, especially as hotter and more humid climates contribute positively to mosquito populations.

“It is impossible to make mosquitoes go extinct,” Yamanaka said. “(But) depending on one tool to control them is dangerous. As the climate heats up, it creates even more favourable conditions for them to multiply, and they’re only likely to become a bigger problem.”