Mosquitoes: Why they're drawn to certain people, and how they're affected by climate change

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An Asian tiger mosquito. Photo credit: WikiImages/CC 2.0, via Pixabay

"Destroyer of worlds" and "apex predator" are how Timothy Winegard describes a common global pest in his new book, "The Mosquito: A Human History of Our Deadliest Predator." He argues that mosquitoes have been the deciding factor in countless wars, that they’ve killed more people (some 52 billion) than any other single cause in history, and they've shaped the path of human civilization. 

Climate change brings both good and bad news when it comes to mosquitoes, he reveals: there's been an annual decrease in malaria rates, but a re-emergence of other mosquito-borne diseases. He points to research that shows 4 billion people are at risk of dengue fever alone. "We're seeing the spread of dengue into other places where it hasn't been or hasn't been for quite a while. Zika obviously, West Nile, Chikungunya -- so some of these other mosquito-borne diseases are emerging or reemerging," he says. 

We asked Winegard to do some myth-busting about the cold-blooded insect. 

Only female mosquitoes bite. And they're drawn to certain people over others.

Winegard explains that mosquitoes need blood to grow and mature their eggs, and research says they prefer blood type O over type A, B, and their blend. 

He says roughly 85% of what makes a person attractive (or not) to mosquitoes is hardwired into their genes. That includes chemical and bacterial levels in and on skin, and the body's natural emissions of carbon dioxide. 

Mosquitoes are particularly drawn to bacteria on human feet and certain perfumes, Winegard notes, and if we miss one spot when applying insect repellent, mosquitoes will be able to find that "chink in our armor."  

Mosquito swarms can kill a human in two hours

"In the Arctic, mosquitoes can bleed young caribou to death at a bite rate of 9000 bites per minute. So if you extrapolate that to a human, it would drain half the human blood in roughly two hours," says Winegard. 

There are some good purposes of mosquitoes

"Because the male’s world revolves around essentially nectar and reproduction, males do pollinate plants and flowers. Keep in mind, of the roughly 30,500 mosquito species, the majority do not vector or transmit diseases. So I don't think anybody in the scientific community is promoting the absolute eradication of mosquitoes from the planet," Winegard says. 

The possibility of gene-editing mosquitoes 

Winegard suggests scientists might be able to use CRISPR gene-editing technology to release a certain species of mosquitoes into the wild, or make them pass down a gene that renders them harmless, thereby bringing down the disease while not eradicating the mosquito species. 

--Written by Amy Ta, produced by Nihar Patel 

Credits

Guest:
Timothy C. Winegard - author of “The Mosquito: A Human History of Our Deadliest Predator”

Host:
Barbara Bogaev

Producers:
Sarah Sweeney, Michell Eloy, Amy Ta, Rosalie Atkinson, Brian Hardzinski, Devan Schwartz