Spiders are usually creatures in people’s nightmares, but a new study shows that perhaps wasps should be. In particular the species Reclinervellus nielseni that can hijack a spiders body and turn it into a ‘zombie spider.’
R. nielseni is a newly discovered species of wasp that uses a host manipulation strategy on spiders. They lay their eggs on the back of a spider and when the larvae hatch, they hijack the body of the spider only to devour it when they’re done with it. When the larva takes over the spider, it feeds on its body fluids for several days. After about 10 days R. nielseni takes over the spider and controls it to build webs in order to keep the larvae safe until they are fully grown and can leave the spider.
In order to understand how this process works, researchers studied the web building habits of a species of spider, the Cyclosa argenteoalba. Under normal conditions, this species of spider builds two different types of webs. First of all, there’s the orb web, which is used for catching insects, and then there’s the resting web, which the spider builds in preparation to molt.
When a spider has been taken over by a wasp, it is forced to build a cocoon web, which is similar to the resting web but is several times stronger on the outside, which gives the developing wasp protection. They team conducting the study also found the centre of web where the cocoon is, is about 30 times stronger than the centre of a normal resting web. These cocoon webs contain ornaments that are presumed to reflect light and give warning to other insects to prevent them from hitting the web and harming the wasp.
After the cocoon web is increased, the wasp controls the spider to go to the centre of the web where it kills it. The wasps that take over these spiders are thought to have taken over the spider by manipulating the hormones involved in molting.