Social spiders have very different hunting strategies

Most spiders are anti-social, spinning their solitary webs to catch prey that wanders into some lonely corner. However, a few spiders have evolved social behaviors and hunt together. 

In a new study led by the University of Portsmouth, experts have investigated the various hunting behaviors of social spiders. The scientists looked at the time it took for the first spider to attack a prey species, the number of spiders attacking a prey species, and the size of prey preferred. The study used grasshoppers, crickets and locusts as prey species.  

The researchers observed that each of the three social spider species in the genus Stegodyphus hunted their prey differently. 

“When spiders become social, they all end up becoming extremely inbred, they start caring for each other’s babies, and they hunt and feed together. What’s new in this study is that, despite these general similarities, we found there is not just one way of being a social spider. Environmental conditions and competition will have shaped different hunting strategies in different species,” explained study lead author Dr. Lena Grinsted.

The Indian cooperative spider (Stegodyphus sarasinorum) attacked prey in large numbers, irrespective of the prey’s size, while most of the spiders attacked smaller prey. Interestingly, the African social spider (Stegodyphus dumicola) seemed to prefer medium-sized prey, with more spiders attacking smaller prey and fewer attacking larger prey.​​ 

The African velvet social spider (Stegodyphus mimosarum), which lives in the same area as the African social spider, hunted differently. African velvet social spiders were found to be shy, rejecting many potential prey species. They were slow to attack, regardless of size. 

“This indicates that where two different social species share the same habitat, they have evolved their own niches in response to competition between them,” said Dr. Grinsted.

The research is published in the Journal of Arachnology.

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By Erin Moody , Earth.com Staff Writer