Scientists discover a new parasitic wasp that creates zombies of spiders

In the Ecuadorian Amazon, a recently discovered wasp is turning a social spider into a heavy, lonely zombie.

The species of spider, Anelosimus eximius, Create bucket-type canvases crafted with thousands of family members. She is considered a "social spider" because she co-operates with other spiders from her common home by sharing hunting, education and feeding tasks.

That is to say until one Zatypota The parasitoid wasp lays an egg on its abdomen.

Once the egg deposited by the wasp hatched, a larva emerges, attaching itself to the spider and feeding on it, sucking the blood-like hemolymph to survive. At this point, the behavior of the spider changes and becomes slave to the larva. She moves away from her nest to create her own cocoon-shaped veil.

The larva feeds on the spider until it dies, in the relative safety of the cocoon-like web that its host has just constructed before turning its own cocoon and eventually becoming a beautiful royal wasp.

Brutal.

Philippe Fernandez-Fournier noticed the strange behavior of the spider and began to investigate. Anelosimus eximius do not usually give up their nests, but when he saw one crawl to create a brand new canvas, he was intrigued.

His research, published in Ecological Entomology, suggests that the larva of Zatypota The wasp species are able to manipulate the activity of their host, controlling their behavior and forcing them to build these unusual canvases – and this is perhaps the most advanced behavioral manipulation ever seen.

Fernandez-Fournier and his research team suspect the wasp of causing spider behavioral changes by "tapping into an ancestral dispersal program" … which is very similar to brain control. This is the wasp that causes starvation of spiders, forcing them to look for food on the periphery of the nest. Once out, they begin to weave webs unlike those they usually inhabit.

In the animal kingdom, the zombifying abilities of wasps are not new. Other species of spiders, such as the Orb Weaver, are also becoming reluctant hosts for wasps and there are species of wasps that do this to cockroaches, as well. However, the recently discovered wasp appears to be much more intensely modifying the development of the web and the social behavior of this particular species of spider.

How could the wasp larva do that? The answer to this question is not so easy to find, but several theories have been advanced, including the injection of hormones into the spider that diverts the trend of the host to build "reduced canvases during moulting". Other species of parasitoid wasps sting the brain of their hosts with a chemical cocktail.

The researchers also found that the size of the spider colony plays a role in the number of spiders that undergo zombie treatment, with the larger colonies seeing more spiders parasitized. This may seem like an obvious link to establish, but it is important to establish the dynamics between the parasite and the host and can help to better understand the evolutionary mechanisms at play in the sinister relationship.

Brutal.

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