Parasitoid wasps may turn spiders into zombies by hacking their internal code

APRIL 29, 2019

by Smithsonian Tropical Research Institute

Parasitoid wasps lay their eggs on a spider's back. This team proposes that by injecting the spider host with the molting hormone, ecdysone, the wasp induces the spider to make a special web for the wasp's pupa.

Setting off a startling chain of events, a parasitoid wasp can force a spider to weave a special web to suspend the wasp pupa just before it finishes killing its 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.

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