Swarms of Supersize Mosquitoes Besiege North Carolina
Two weeks ago, Hurricane Florence slammed into the Carolinas, unleashing six months of rain in a matter of hours. In inland Cumberland County, the Cape Fear River rose 40 feet1, inundating Fayetteville with the worst flooding the city has seen since 1945. But as the waters receded and citizens returned to their ruined homes, a new plague was just beginning to descend.
Drive through Fayetteville today and you’ll pass house after house emptied of belongings, the mud-stained detritus piled high on curbs across the county. But you’ll have a hard time seeing the storm’s aftermath through the clouds of monstrous, hyperaggressive mosquitoes spattering across your windshield. Twenty-seven counties in North Carolina, including Cumberland, are in the midst of a mega-mosquito outbreak. On September 26, North Carolina governor Roy Cooper ordered $4 million in relief funds to combat invading swarms of the nickel-sized bloodsuckers, known to scientists as Psorophora ciliata and to everyone else as gallinippers.
“They’re just everywhere,” says Tom Turturro, an environmental health program specialist with Cumberland County. The area gets a small amount of gallinipper activity each year during the rainy season, but this has been an especially bad bout. His office has gotten more than 500 calls in the last week. Worried it will hamper clean-up efforts, the county sent out pesticide-spraying trucks this week, and is looking into aerial efforts as well. While not known to transmit human disease, the supersize skeeters are quick to mob any mammal they can find, any time, day or night, and deliver a fearsome bite. “It’s like somebody shoving a hot poker in your arm,” says Turturro. “It burns like hell.”
All mosquitoes come equipped with serrated mouthparts called maxillae they use to carve through skin. For most species, these structures are so small and sharp that you don’t feel much more than a tingle to let you know you’ve been bitten. But the gallinipper’s chompers are designed for bigger prey—it’s one of the only species that can pierce cattle hide. Its bite is so deep it sets off nerve cells in the epidermis designed to alert the body to a serious wound. In other words, your body thinks it’s being stabbed.
“It’s a much more intense pain because if that part of our skin has been compromised, that means the body is in big trouble,” says Deby Cassill, a biologist at the University of South Florida St. Petersburg.
While the giant mosquito can usually be found in low numbers throughout the southeastern US, Cassil says the animal is native to the swamplands of the Mississippi delta. Pressure from pesticides and human development in more populous parts of the region have caused other mosquito species to become smaller and reproduce faster—sometimes up to multiple generations in a year. But Psorophora ciliata has a different strategy. The massive females overproduce eggs, laying them in the millions in low-lying grasslands. Most will dry up and die over the next year or two. But should a big rain roll through, any viable eggs will quickly hatch. “They’re adapted to these rare events where they can really benefit,” says Cassill. “It’s kind of like a dinosaur in that way.”
So what happens as these rare flooding events, like Florence, increase in frequency?
The Intergovernmental Panel on Climate Change has said that the science isn’t clear on whether a warming planet will deliver more hurricanes, only that any hurricanes that do happen will be worse. More moisture in the atmosphere and warmer seas mean more rain and more storms like Florence and Harvey, which park for days over the coast.
“It’s a great question, and a really hard one for scientists to predict,” says Michael Reiskind, a public health entomologist at North Carolina State University. “But I have to think that if every single year we had a major flooding event like Florence, populations of these mosquitoes would go up.” More frequent flooding would mean lower egg mortality year to year—the thing that, for the moment, is keeping giant mosquitoes from being an annual scourge.
Humans have worked hard over the centuries to minimize the flooding that was a natural part of the coastal ecosystem—draining swamps and rerouting rivers, installing dams and levies to protect growing cities. But all those measures weren’t designed to withstand the new extreme weather events of a climate-changed world. Often, it actually makes matters worse.
Super-fueled hurricane seasons threaten to bring recurring floods to the American South in the near future. And with them, a six-legged pestilence. “Wherever in our country gets warmer and wetter, the insects are going to come,” Cassill says. The resulting impacts could be more than just a few bad bug bites. Recently, researchers estimated that for every degree Celsius of warming, 10 to 25 percent of the world’s crops will be lost to insects. And that’s a scourge that will require more than some DEET and well-screened windows to ward off.