Why climate change means more huge mosquito swarms in the Arctic

Global warming is already underway, taking a toll on the Arctic sea ice and various wildlife populations such as the polar bears, but mosquitoes are thriving.

As temperatures warm in the Arctic, mosquitoes are not only able to emerge earlier from their ponds, but also to grow faster and survive even longer – and in higher numbers, according to a new study.  

The researchers focused their study on Western Greenland and were expecting to find a decrease in the number of Arctic mosquitoes, which would have triggered conservation efforts, according to Lauren Culler, lead author of the study and postdoctoral researcher at Dartmouth College’s Dickey Center Institute of Arctic Studies.

Researchers measured the impact of increasing temperatures on development and death rates from predation on immature mosquitoes. Then, they developed a climate-population model to analyze mosquito survival – from immature stages to the adult biting stage – across a range of temperatures in future climate change scenarios in the Arctic.

Arctic mosquito eggs develop and hatch in shallow, temporary ponds of springtime snowmelt. The research reveals that warming temperatures cause the mosquitoes to hatch earlier and shortens their development time through the larval and pupal stages by about 10 percent – when they are vulnerable to aquatic predators such as diving beetles. This increases their chances of surviving until adulthood.

If Arctic temperatures rise 2 degrees Celsius, the study predicts, the probability of immature mosquitoes surviving to adulthood could increase 53 percent.

Rising mosquito numbers will likely have serious consequences for caribou and reindeer herds, which are one of the main food resources for Arctic communities, the researchers warn.

"Increased mosquito abundance, in addition to northward range expansions of additional pest species, will have negative consequences for the health and reproduction of caribou," said Ms. Culler in a press release. "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."

Though it's possible for a swarm of mosquitoes to take down a caribou, the grazers are known to change their behavior in response to harassment from the flying pests “by abandoning areas for more isolated ones such as snowy patches or windy ridges,” according to The Guardian. This means they spend less time eating and their population drop.

"Every moment that a caribou spends avoiding insects is another minute that they're not doing what caribou need to do so that they feed so that they can successfully raise calves," Culler told VICE last month.