Read the full, horrifying, text here, where you can also watch a video of the zombie in action.
Having partially developed inside caterpillars, the larvae of the wasps manipulate their hosts into watching over them as a mother or bodyguard might.
A team that has done extensive field studies with infected caterpillars say they have the first conclusive proof that the manipulative behaviour of some parasitoids increases their chance of survival.
The parasitoid wasp Glyptapanteles lays its eggs, about 80 at a time, in young geometrid caterpillars. The eggs hatch and the larvae feed on the caterpillar's body fluids. When they are fully developed, they eat through the caterpillar's skin, attach themselves to a nearby branch or leaf and wrap themselves up in a cocoon. ... At this point, something remarkable and slightly eerie happens.
The caterpillar, still alive, behaves as though controlled by the cocooned larvae. Instead of going about its usual daily business, it stands arched over the cocoons without moving away or feeding.
The caterpillar – now effectively a zombie – stays alive until the adult wasps hatch.
"We don't know exactly what kills the caterpillars, but it is fascinating that the moment of death seems to be tuned to the duration of the wasp's pupal stage," says Arne Janssen of the University of Amsterdam.
Saturday, June 07, 2008
The New Scientist ran an article June 4th on wasp/caterpilar parisitism: