This Spider Can Eavesdrop on Its Sexual Rivals
Not only is courtship a learned behavior, but spiders pick it up quickly
By Elizabeth Armstrong Moore,  Newser Staff
Posted Aug 6, 2015 7:55 AM CDT
The brush-legged wolf spider.   (Wikimedia Commons / Redamp19)

(Newser) – It doesn't take much observational power to note that spiders have tiny brains. Really tiny. So the recent finding out of the University of Cincinnati—that they learn how to court mates by eavesdropping on the competition—is all the more impressive. "It’s a complex set of behaviors for a tiny little brain," says biologist George Uetz of the brush-legged wolf spider his team studied in a lab, noting that the discovery "has completely changed our way of thinking about this little spider." Discovery News explains that mating is "all about the leg tapping" for these spiders, who try to wow females with a distinct series of taps. The spiders are found in the eastern US and Canada, but researchers used lab-raised ones who hadn't witnessed mating rituals in their experiments.

Reporting in the journal Animal Behaviour, researchers say that when the spiders were shown videos of wild males tapping their legs to court females, the lab-raised ones could mimic and even master this behavior—and in just a matter of four days. "We thought because they were invertebrates with a tiny brain, everything about them is genetically regulated in a hardwired nervous system, ie, they respond instinctively because it's programmed into their nervous system," says Uetz. Instead, "Not only do they learn from visual cues but also from vibration cues." Quickly picking up on what's going on is a good thing, as mating is a risky business for these guys. If the tapping doesn't impress the female, she'll try to eat the male. Even among males that successfully court their females and mate, up to 12% are still eaten anyway. (This animal mates to the point of death.)