A New Mosquito-Hunting Spider Could Help Fight Malaria

It’s time to get over your fear of spiders, because this recently discovered species could save lives.

A male Evarcha culicivora. (Photo: Fiona Cross)

Aug 17, 2015· 1 MIN READ
David McNair is an award-winning reporter and editor based in Charlottesville, Va. He runs the hyper-local news site The DTM and his fiction has appeared in Virginia Quarterly Review.

A spider dubbed the “mosquito terminator” could become the newest hero in the fight against malaria.

According to researchers in Africa, Evarcha culicivora is a spider found around Lake Victoria in East Africa that loves feasting on human blood because it gives it an odor that’s sexually attractive to potential mates. But dont worry—unfortunately for these spiders (and fortunately for humankind), they dont have the oral equipment to pierce human skin. So what’s a spider to do? Hunt female mosquitoes that have recently drawn blood from humans.

“This is unique. There’s no other animal that targets its prey based on what that prey has eaten,” Fiona Cross, an arachnologist and coauthor of a recent study of spiders and predatory specialization published in the Journal of Arachnology, told SciDev.net.

The spiders, which typically live on walls inside homes, are able to identify when a female mosquito has drawn blood by recognizing a resting posture she adopts after feeding.

“Their compound eyes give them clear eyesight. And just like a cat, they stalk their prey and pounce on them at the right moment,” Cross said.

Malaria claims more than half a million lives annually, according to the World Health Organization, many of whom are young children living in Africa.

Of course, while residents don’t want to be around mosquitoes carrying the deadly malaria parasite, having spiders in the house isn’t an appealing solution—and getting people to see them as allies will be part of the challenge.

“People need to know that these organisms are harmless and will not attack them,” Cross said.

It’s not just spiders. A host of biological control methods are being researched and deployed. Fish, crustaceans, lizards, and several other creatures often consider mosquitoes and mosquito larvae a pretty good meal.

Nile tilapia, for example, is a fish native to Kenya that feeds on mosquito larvae. Researchers found that after they placed the fish in several mosquito-infested ponds for 15 weeks, the number of mosquito larvae dropped by 94 percent. They also discovered that a plankton in the crab family, which acts as a natural pesticide by feeding on mosquito larvae, might be more effective than commonly used biological insecticides.

In addition, natural chemicals can mask what attracts mosquitoes to humans, and African plant oils distilled in candles can serve as a mosquito repellent. Research also suggests that dragonflies, bats, birds, and even turtles could be used in the fight against malaria.

But while biological control methods are important, malaria expert Njagi Kiambo of Kenya’s Ministry of Health pointed out to SciDev.net, “We cannot solely rely on them, as their impact is minimal compared to chemical interventions like insecticides and putting on bednets.”

Less creepy-crawly alternatives are being tested, including a single-shot malaria drug and the world’s first malaria vaccine.