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These blood-loving spiders could help fight malaria

Evarcha culicivora loves drinking human blood -- but it doesn't bite you to do it. (Robert Jackson/ University of Canterbury)
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A spider with a taste for human blood? That's some scary stuff. But when those spiders sate their thirst by attacking deadly mosquitoes, they turn from nightmare monsters to potential allies.

Researchers have been interested in a jumping spider called Evarcha culicivora for that reason for quite some time now. The spiders, which are native to East Africa, are unusually picky eaters. Instead of going after any old bug -- or even any old mosquito -- they hone in on females with bellies full of blood.

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That's great news in the fight against malaria, which kills half a million people each year according to the World Health Organization. With the release of her latest study on the spider's behavior, International Centre of Insect Physiology and Ecology arachnologist Fiona Cross is repeating what she and her colleagues have been saying for years: These spiders are our friends, and we should welcome them into our homes.

The new study, published recently in the Journal of Arachnology, reiterated that the spiders are perfect for our needs. They lack the mouth equipment to bite humans, but they specifically target mosquitoes who have just fed on blood, which the spiders identify based on the postures of their abdomens. This bloody meal makes them irresistible to the opposite sex.

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They also prefer the species of mosquito that carries the malaria parasite, and unlike another species of mosquito-eating spider, they live inside people's homes -- in fact, they're attracted to human body odor. One study found that they were really into the stench of smelly socks.

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

The spider is one of several living critters that can help cut down on the pervasiveness of the parasite, but these arachnids and their fellow mosquito lovers won't make malaria disappear. Instead, researchers say, they should be considered an important part of our natural defense against the illness.

And those in East Africa should do their best to let the little guys jump around their homes -- though that may be easier said than done, if they insist on hanging out in piles of dirty laundry.

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