Novelty is no good if you're an arachnid. Spiders get a personality boost from hanging out with the same group day in and day out, new research finds.
The study examined a bizarre species of social spiders that build communal nests as big as cars. Results showed that social interactions can shape an animal's personality, said study leader Andreas Modlmeier, a postdoctoral researcher at the University of Pittsburgh.
"If you live in the same group for a long time, with the same individuals, you are able to specialize in your own niche, and therefore avoid conflict with other group members," Modlmeier told Live Science.
The study builds on a theory of animal behavior known as "social niche specialization." The idea is that within social groups, individuals have to stand out from each other, and will thus develop distinct personalities — defined, in this case, as differences in behavior. The notion of a spider with personality may seem strange, but animals from cats to bees have been found to show individual personality differences.
Modlmeier and his colleagues tested the theory on Stegodyphus dumicola, a social spider native to the Kalahari Desert in southern Africa. These spiders live together in communally built webs of up to 2,000 individuals, Modlmeier said. They share the responsibility of guarding every community member's eggs and young, and hunt together for prey. When adult females die, they liquefy their inner organs to feed the young of the colony, a behavior called gerontophagy. [Images: Creepy, Crawly and Incredible Spiders]
The researchers created 84 colonies of six spiders each. After a period of time, the researchers disturbed the colonies, forcing the spiders to rebuild the structures. But in half the cases, the researchers simply dumped the spiders out of their containers and put them back in a new container with the same individuals. In the other half, the researchers dumped the spiders out and mixed up their groups.
The researchers also looked at the spiders' personalities, by testing the arachnid's boldness. By puffing air at each spider, the scientists mimicked an attempted attack by a predator, and then timed how long it took for the spider to move again. The less time it took to move again, the bolder that spider.