MSU scientists lead battle against mosquitoes, pesky insects
MSU scientists recently made discoveries about the biology of insects that will aid in the ongoing fight against summer’s peskiest pests.
Ke Dong, MSU toxicologist and neurobiologist and senior author of the paper, which appeared in the Proceedings of the National Academy of Sciences, has a lab in MSU’s Department of Entomology that has been dedicated to the study of insecticides for the past 15 years.
Dong said the research was done on the effect the popular pyrethroid insecticide has on mosquitoes and other insects, as well as why insects develop resistance over time.
Dong said the sodium channel, a very important aspect of the nervous system for both humans and insects, plays a crucial role in the effectiveness of pyrethroids. She said pyrethroids latch onto a receptor site within the sodium channel. This causes the channel to open, which ultimately kills the insects from a sodium overdose. It was previously believed there is only one receptor site in insect sodium channels.
Dong said their research, partly funded by the National Institutes of Health, found there is a second receptor site in the insects’ sodium channels, one that is not found in humans.
“The discovery of a second receptor site is a mark of significant advance in the field of insect toxicology and neurobiology,” said Yuzhe Du, an MSU electrophysiologist and a lead author in the paper.
Another important result to the research, which began three years ago, was the understanding of how and why insects are developing resistance to pyrethroids. Dong said resistance can become a serious global problem that can come from overuse of the insecticide.
“One thing we expected to find out is how to prevent the development of resistance,” Dong said. “Our research should (also) be able to help people monitor resistance in the field.”
Resistance comes from mutations in the receptor sites in the sodium channel that render pyrethroid effects useless. These mutations are naturally occurring and threaten to overtake the insect population if all the nonmutated insects are being constantly wiped out, Dong said. She added the lab studied mutant mosquitoes from all over the world.
Du said the discovery of the second receptor site also explained much of the mutations that result in resistance.
With these discoveries, insecticides can be manipulated to target the second receptor site in addition to overcoming the obstacles that are presented by the mutations. This is necessary for the prevention of the spread of diseases such as malaria, dengue fever and West Nile virus that are transmitted by mosquitoes. Pyrethroids are also used for cockroach control and are used in shampoos for head lice, Dong said. This also could lead to advances in agricultural pest control.
Psychology junior Nathan Rabens is glad MSU is making further strides toward the better control of pests.
“I really hate bugs, and mosquitoes are the worst,” Rabens said. “The less bites for me, the happier everyone will be.”
Dong said it’s important to continue researching mosquitoes and other insects in order to continue to find weak links and to battle resistance.
“We basically want a safer insecticide and a new one that can overcome resistance problems and be relatively safer to humans,” Dong said.