Mosquitoes in the rapidly warming Arctic are not only able to grow faster, but they’re also emerging from their ponds earlier and in higher numbers, according to new findings published in Proceedings of the Royal Society B this week.
Arctic mosquitoes develop in the shallow temporary ponds that form on the tundra during the springtime snowmelt. In western Greenland, mosquitoes are the dominant biting pests, but they’re also pollinators of tundra plants and an important part of the food web – as prey items for beetles and birds, for example. In the past century, average Arctic temperatures have increased at twice the global rate, changing the timing and intensity of mosquito emergence.
A Dartmouth trio led by Lauren Culler combined controlled experiments with field observations in western Greenland to measure the impacts of rising temperatures on the development of immature mosquitoes and predation rates on them. Then, the researchers created a climate-population model to study mosquito survival – from immature stages to the adult biting stage – across a range of temperatures in future climate change scenarios.
Warmer spring temperatures caused mosquitoes to emerge two weeks earlier, they found, and this also shortened the development time of their more vulnerable juvenile stages by about 10% for every 1 degree Celsius increase. So even though higher temperatures increased the amount of mosquitoes being eaten by diving beetles (their top predators), the accelerated growth through their larval and pupal stages meant less exposure to their aquatic would-be predators, increasing their survival rate overall.
If Arctic temperatures rise 2 degrees Celsius, the likelihood of mosquito survival increases by 53%, the model predicts.
Furthermore, warming synchronizes their life cycle with caribou calving season. That means bloodsucking female mosquitoes get to feed on a larger, less mobile herd. “Increased mosquito abundance, in addition to northward range expansions of additional pest species, will have negative consequences for the health and reproduction of caribou,” Culler said in a statement. Wild caribou and managed reindeer are an important subsistence resource for local communities.
Warming temperatures are causing Arctic mosquitoes to grow faster and emerge earlier, significantly boosting their population and threatening the caribou they feast on. Lauren Culler
All images: Lauren Culler