A version of this post first appeared on June 7, 2012. Happy Halloween!
It's reasonable for a hungry predator to hesitate when its prey appears to be two halves of an animal glued together and reanimated. Jumping vampire spiders that were faced with this decision took it slowly. But they eventually chose tasty mosquitos stuffed full of fresh human blood. Before pouncing, these discriminating diners considered their victims' headwear as well as their belly size.
New Zealand biologist Ximena Nelson led the investigation of how Evarcha culicivora spiders choose which prey to attack. The East African jumping spiders are very picky eaters, dining solely on mosquitos that have recently filled up on blood. (Since only female mosquitos drink blood, this means males are mostly off the menu.)
A blood meal doesn't just satisfy a rumbly abdomen; it also makes the spiders more attractive to the opposite sex. So it's worth ...
