吸血蜘蛛专挑雌性蚊子?

Vampire spiders, as the name suggests, like blood. And they feast on blood-filled mosquitoes to get it. But only female mosquitoes suck blood. So how do spiders home in on the ladies?

To find out, researchers, well, took apart a bunch of mosquitoes. Then they mixed and matched body parts. They glued female heads onto male abdomens and male heads onto female bodies, some of which had blood-filled bellies. Then they let the spiders loose near these reassembled specimens, and watched to see which ones the spiders stalked.

As the researchers predicted, the spiders paid close attention to the abdomen, pouncing on the Frankensquitos filled with blood. But the spiders also kept an eye—or eight eyes—on the mosquitoes' heads. Males have lush, feathery antennae. The females aren't as showy. So if the spiders couldn't see the belly they went for female-headed skeeters, presumably for the better odds of scoring blood. The research is in the Journal of Experimental Biology. [Ximena J. Nelson and Robert R. Jackson: "The discerning predator: decision rules underlying prey classification by a mosquito-eating jumping spider"]

Previous studies have shown that blood meals give vampire spiders a perfume that's irresistible to the opposite sex. Now that’s what I call blood lust.

—Christopher Intagliata