Survival of the fittest. This is the law of the jungle. The very same tactic that is used by parasitoid wasps. The wasps zombify spiders and make them weave a special web. Then, the wasps use the web to suspend themselves before they finally kill their spider host.
William Eberhard, staff scientist emeritus at the Smithsonian Tropical Research Institute and Marcelo Gonzaga at the Universidade Federal de Uberlândia in Brazil have assembled wide-ranging evidence that 'zombification' involves hacking existing web-spinning mechanisms by hijacking the spider's own molting hormone, ecdysone.
In a new paper published in the Biological Journal of the Linnean Society they combined a review of all known reports of different wasp species known to zombify different spider species around the world; the results from a molecular study in Brazil; and new observations of Costa Rican spiders to demonstrate several previously unappreciated patterns that suggest that the wasp larvae use ecdysone.
It is really impressive how the wasps induce the spider to modify the design of the web. The net made by the controlled spider is forty times stronger than the conventional one thus becoming a stable home for the pupal cocoon.
(Image Credit: Marcelo O. Gonzaga)