Spider 'Friendships' Spark Personalities

Novelty isn't something to boast about if you're an arachnid. Spiders get a personality boost from long-term "friendships" with fellow web-weavers, a new study finds.

Stegodyphus dumicola, native to the Kalahari Desert in southern Africa, is such an example of this kind of social spider. According to results, social interactions can shape an animal's personality.

"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," study leader Andreas Modlmeier, a postdoctoral researcher at the University of Pittsburgh, told Live Science.

The study builds on a theory known as "social niche specialization" - the idea that within social groups, individuals have to stand out from one other. In this case, the spiders develop differing personalities, exhibited by differences in their behavior deemed "shy" or "bold."

Modlmeier and his colleagues tested the theory on Stegodyphus dumicola, which live together in communally built webs of up to 2,000 individuals.

The researchers created 84 colonies of six spiders each. Eventually they would disturb these communities, either by simply swapping one container for a new one, or by mixing up the groups of spiders.

Overall, spiders became shyer after they were disturbed, meaning they hardly moved after experiencing a simulated attack by a predator using puffs of air.

Interestingly, spiders that remained close with their same buddies over the course of the experiment became more consistent in their behavior over time, and more divergent from one another. In other words, these arachnids settled into two personality categories: bold and shy. Researchers determined this by the way they responded to fake attacks, either by daringly exhibiting movement or quietly staying still.

On the flip side, spiders that were introduced to new "friends" were less comfortable, so to speak, into settling into a distinct personality or niche.

"It's a huge part of what makes social groups successful and effective," Modlmeier explained to Live Science. "If you have a very efficient group that works together well, where everyone knows their place and has a task to work on, that group will be much more successful."

The researchers reported their findings in the journal Biology Letters.