Biologists at Washington University have discovered that an invasive species of mosquito in the U.S. has adapted to colder climates by laying eggs that can survive harsh winters.
Researchers at Wash U’s Tyson Research Center and the University of Central Florida wanted to know how the Asian tiger mosquito can survive in northern areas like Iowa and New Jersey. The species first appeared in Texas in the mid-1980s and can transmit the West Nile, dengue, Zika and chikungunya viruses.
The mosquitoes live for only a few weeks, so they can adapt to new conditions in a short amount of time, said Kim Medley, director of the Tyson Research Center.
“They can complete multiple generations in a single growing season,” Medley said. “Rapid adaptation is a more common phenomenon than scientists or anyone thought a few decades ago.”
Researchers collected mosquito eggs and larvae near cities at the center of the species’ range, such as Huntsville, Alabama. They also collected specimens near cities along the northern edge of its range, like Peoria, Illinois. After raising the mosquitoes and producing eggs in the laboratory, the scientists placed the eggs in multiple locations within and outside of the Asian tiger mosquito’s range to see how well they would survive winter.
Once the eggs were brought back to the laboratory after the winter, researchers found that the dormant eggs laid by northern mosquitoes survived better than those from southern members of the species. The results were published last week in the Journal of Applied Ecology.
The findings suggest that the Asian tiger mosquito likely will keep moving north. There isn’t enough data to say how climate change could affect where the species spreads in the U.S., Medley said.
The next steps involve studying how much urban landscapes can drive adaptation for the mosquitoes and what public health concerns could develop as the species becomes more abundant in northern areas of the U.S.
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