Meet the Vampire Spider

University of Canterbury
University of Canterbury / University of Canterbury

Evarcha culicivora is a tiny spider that lives around Lake Victoria in East Africa, and it has a taste for blood. Don’t worry about one biting you like Dracula on eight legs, though. The spider doesn’t have the piercing mouthparts to get through your skin and into your veins. Instead, it goes about vampirism in a more roundabout way.

With its acute eyesight and smell and the ability to leap several feet, the spider is an excellent bug stalker. Given a choice of prey in laboratory experiments, E. culicivora shows a clear preference for female mosquitoes that have recently fed on mammal blood, and can even sniff out these blood-filled skeeters without even seeing them. It’s the only animal scientists know of that chooses its prey based on the prey’s own meals. 

Going through a middleman saves the spiders a lot of trouble in their hunt for blood. Even if it had the right anatomical equipment for feeding directly on humans or other large animals, doing so could get it swatted or squashed. Hunting mosquitoes is much less risky.

The spiders’ indirect vampirism could be good for humans, too. They selectively target mosquitoes from the genus Anopeheles, one of the main vectors for malaria. The spiders can be as picky as they are because their sharp eyes allow them to distinguish different mosquito species based on posture, and different sexes based on the shape of the insects’ antennae.