How a Tiny Spider from the Desert Captures Prey Four Times its Size

A tiny spider from the Negev desert in Israel likes to go big or go home. This small arachnid routinely preys on insects up to almost four times its own size. Now, scientists have found out how this spider accomplishes this seemingly impossible fet.

The ant-eating Zodarion cyrenaicum spider feeds almost exclusively on the Messor arenarius ant, which can grow up to 17 millimeters. In constrast, the tiny spider grows just up to three millimeters. Yet despite its small size, the spider chooses to feed almost exclusively on the larger ants, even though there are smaller ones available.

In fact, other Zodarion species choose smaller ants that are comparable to their own size. In this case, the researchers believe that the tiny spiders recognize a specific component of a pheromone produced by Messor ants.

So how does the spider manage this feat? There are several different strategies that the spiders use, depending on their gender and size. Juveniles tend to climb on the dorsal side of an ant and then deliver an immobilizing bite to the abdomen; this avoids retaliation by the helpless prey. Adult spiders have venom glands that are almost 50 times larger than those of the juveniles, which give them a leg up. The adult spiders inject more venom into their prey and capture them that way.

"Specialized capture combined with very effective venom enables this ant-eating spider to capture giant prey," said Stano Pekar, one of the researchers, in a news release.

The findings reveal a little bit more about how these small spiders manage to capture such giant prey. With their venom and capture methods, these spiders can focus on bringing down creatures that are four times their size

The findings are published in the journal Naturwissenchaften.