Climate Change and Mosquitoes: Arctic Populations Thrive Despite Predation

Climate change is having serious effects on mosquito populations. A study of Arctic mosquitoes found that if tundra climates increase by even two degrees Celsius, more than 50 percent more of adult mosquitoes will grow faster and emerge as adults sooner. According to researchers from Dartmouth College, this also has a serious impact on the caribou populations they feed on.

"Increased mosquito abundance, in addition to northward range expansions of additional pest species, will have negative consequences for the health and reproduction of caribou," Lauren Culler, lead author and a postdoctoral researcher at Dartmouth's Dickey Center's Institute of Arctic Studies, said in a statement. "Warming in the Arctic can thus challenge the sustainability of wild caribou and managed reindeer in Fennoscandia (Norway, Sweden, Finland and parts of northwest Russia), which are an important subsistence resource for local communities."

According to a news release, Arctic mosquitoes, particularly those found in western Greeland, develop in shallow ponds formed from spring snowmelt. In order to reproduce, female Arctic mosquitoes are dependent on a blood meal – most often provided by unwilling caribou calves.

For their study, researchers developed a climate-population model of Arctic mosquitoes and their predators, including their top predator, the diving beetle. After evaluating the mosquito's survival and development across a range of forcasted Arctic temperatures, researchers found that warming temperatures are affecting the insect's ability to escape predators. On average, mosquitos emerged two weeks early and developed ten percent faster for every degree (Celcius) of spring warming. And since they were able to grow faster, they were able to escape their predators sooner.

Using models that simulated a two degree Celsius rise in spring temperatures, researchers predicted that mosquito survival rate could increase by 53 percent. Their models can be applied to other ecosystems that are sensitive to climate change, the researchers noted.

During caribou calving season, female mosquitos are provided with a larger, less mobile herd to feed on, which also contributes to their increased growth.

The Dartmouth findings were recently published in the journal Proceedings of the Royal Society B: Biological Sciences.

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