Friday , September 30 2022

The recently discovered bee turns social spiders into zombies


The adult stage of the Zatypota parasitoid was a wasp. Credit: Philippe Fernandez-Fournier

It seems to be the smallest horror film in the world: deep in the Ecuadorian Amazon, a newly discovered species of wasp turns a "social" spider into a drones like a zombie abandoning its colony to make the wasp auction.

This is the terrifying discovery in the real life of researchers at the University of British Columbia detailing the first example of a manipulative relationship between a new Zatypota species and social species Anelosimus eximius spider in a study published recently in Ecological entomology.

"The vessels that manipulate the behavior of the spiders have been observed before, but not at such a complex level as this," said Philippe Fernandez-Fournier, lead author of the study and former master student at UBC's Department of Zoology. "Not only does this species target a social species of spider, but it makes it leave its colonies, which rarely does."

Fernandez-Fournier was in Ecuador and studied various types of parasites living in nests Anelosimus eximius spiders, one of about 25 species of "social" spiders around the world. They are remarkable for living together in large colonies that cooperate in catching prey, share parental duties, and rarely move away from their nest-shaped nests.

When Fernandez-Fournier noticed that some spiders were infected with a parasitic larva and saw them wandering a few feet or two away from their colonies to spin closed dense silk webs and foliage, he was puzzled. "It was very strange because I do not normally do that, so I started writing," he said.

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The recently discovered bee turns social spiders into zombies

Zatypota larva killing his host Anelosimus eximius spider. Credit: Philippe Fernandez-Fournier

Intrigued, he carefully took some of the structures, known as "cocoon pods", back to the lab to see what might come from the deep.

To his surprise, it was a wasp.

"These wasps are very elegant and are graceful," said Samantha Straus, co-author of the study and Ph.D. a student in the UBC's zoology department. "But then I do the most brutal things."

Using the data gathered in Ecuador for different projects between 2012 and 2017, researchers have begun to put together the wasp's life cycle and its parasitic relationship with the spider.

What they found was the fascinating and terrifying parts: after an adult vampire finds an egg on a spider's abdomen, the larva opens and attaches itself to the unhappy arachnic host. It is then supposed to feed on the spider's blood hemolimus, growing and slowly taking over the body. Now the "zombie" spider comes out of the colony and rotates a larval cocoon before patiently waiting to be killed and consumed. After a feast on a spider, the larva enters its protected cocoon, appeared fully nine to eleven days later.

<a href = "" title = "Parasitoid Vipera (Zatypota sp.) on its social host Anelosimus eximius spider. Belief: Philippe Fernandez-Fournier ">
The recently discovered bee turns social spiders into zombies

Parazitoid viespe (Zatypota sp.) On its social host Anelosimus eximius spider. Credit: Philippe Fernandez-Fournier

In other similar cases of parasitism, it is known that the wasps target solitary species of spiders as blind weavers and manipulate them in behaviors that are in their normal repertoire.

"But this change in behavior is so difficult," Straus said. "The Vampa completely kills the spider's behavior and brain and makes her do something she would never do, like letting her nest and rotating in a completely different structure. It's very dangerous for these little spiders."

They do not know how to do these wasps, but scientists believe it can be caused by an injection of hormones that make the spider believe in a different stage of life or make it disappear from the colony.

"We think the wasps target these social spiders because they offer a broad and stable colony, a host and a source of food," Straus said. "We also found that the larger the spider's colony, the more it was that these wasps were its target."

Straus, who now has a tattoo of the wasp, will return to Ecuador to investigate whether the wasps are returning to the same generation of spider colonies for generations and what evolutionary advantage they might have.

Meanwhile, strands will continue to play the leading role in the most serious nightmare of spiders.

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More information:
Philippe Fernandez-Fournier et al., Behavioral modification of a social spider by a parasitic wasp, Ecological entomology (2018). DOI: 10.1111 / een.12698

Journal reference:
Ecological entomology

Provided by:
University of British Columbia

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