Parasites who manage the behavior of their hosts for their own benefit are a well-documented natural phenomenon, but the discovery of the previously unknown relationship between parasitic wasp and social spider is particularly disturbing.
The kidnapping of the brains of unsuspecting hosts is the thing that some organisms do, usually for reproductive purposes. Known examples include a sponge that controls the activity of carpenter ants, a unicellular parasite that makes the scent of cat urine irresistible to the rodents, and the worm that causes infected fish to perform complex dance.
Another parasitic relationship discovered by scientists at the University of British Columbia can now be added to this list – and this is one of the worst we've seen, both in terms of complexity and depth. In a new study, published today in ecological entomology, lead author Philippe Fernandez-Fournier describes how Zatypota types of parasitic wasps use and abuse social Anelosimus eximius spider, first use it as an escape and then force it to build an incubation chamber. Oh, and then her spider.
Fernandez-Fournier accidentally encountered a discovery in the Amazon in Ecuador while studying various nesting parasites A. eximius. These arachnids are labeled as social spiders because they live in large colonies, work together to capture prey, share parental responsibilities, and seldom roam for the cozy boundaries of their common basket nests.
These spiders are rigid in their behavior, so Fernandez-Fournier learned when he saw some of these spiders who were infected with a parasitic larva that spread about one or two feet from the colony. This observation was strange and rare to himself, but the UBC scientist also watched as these same spiders began to rotate the belts of densely spun silk and bits of leaves.
"It was very strange because they usually do not, so I started writing notes," said Fernandez-Fournier in his statement.
Curious, he took the coconut fabric back to the lab. When he opened it – to his shock – he saw a developing beard inside. Realizing that he was, Fernandez-Fournier and his team further investigated and uncovered a completely undocumented interaction between the two.
Here works: adult woman Zatypota the wasp puts an egg on her stomach Anelosimus eximius spider. After the larval hatch, he joins the spider and feeds on the blood. The larva grows steadily and a lot of spider's body begins to pass. Eventually, the spider enters the state of "zombification," where it no longer feels like its normal self. Under the influence of the larva, the spider leaves its colony and sets itself up for the task of building the cocoon. Once this forced design task has been completed, the spiders will remain motionless, allowing the larva to complete the task of killing and consuming their host. Satiated, the larva sinks into a web cocoon that uses as an incubator for its next degree of germination. Nine or eleven days later, a fully mature wasp emerges from the cocoon. The cycle begins again, unfortunately for another eight-member victim.
Strategies, scientists say, are unique in that parasitoid wasps were previously only documented as prey on solitary spiders.
"But this change in behavior is so hard," said Samantha Straus, co-author of the study. "Wasp completely denies the behavior of the spider and the brain, and it does something they would never do, like leaving their nest and rotating a completely different structure, which is very dangerous for these tiny spiders."
Straus added: "We think wasps are targeted at these social spiders because they provide a large, stable host colony and food source. We also found that the larger the spider colony, the more likely it is that these wasps would be directed . "
Regarding how the larva is based on hypnotizing spells, scientists know that the spider injects a brain-changing hormone. This hormone either tricks the spider into thinking that it is in another life stage, or it works as a signal that makes a spider flee from its colony. But these are just quarrels.
Fernandez-Fournier and Straus now want to return to the Ecuadorian forest to learn more about these diabolical waxes and their hosts. In particular, they would like to know whether the wasps are repeatedly targeting the same spider colonies and, if so, how this behavior works as an advantage.[Ecological Entomology]