Natures wonders: more on zombification (Introduction)

by David Turell , Friday, April 18, 2025, 19:33 (18 hours, 57 minutes ago) @ David Turell

A very common phenomenon:

https://www.the-scientist.com/how-tiny-organisms-control-minds-create-zombies-and-shape...

"Miniature zombies are all around us, scuttling through the underbrush or flying through the air in nearly every continent on Earth. In Brazil, a fungus takes over ant brains, altering their circadian rhythms and social behaviors. In England, a virus forces caterpillars to climb high into the canopy, then slowly liquefies their bodies, which drip onto the leaves below. In Indonesia, a parasitoid wasp uses specialized venom to alter a cockroach’s brain chemistry, turning it into the perfect host for her young.

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"While many parasites are content to complete their entire lifecycles inside a single host, Leucochloridium species have evolved a more complex—and horrifying—way of life.1 Birds infected with these particular parasites excrete Leucochloridium eggs in their droppings, which are picked up by hapless snails. The worm larvae make their way through the snail’s tissues to its eyestalks, where they form broodsacs, pouches that can contain hundreds of individual larvae. Because the worms need to get back into a bird to complete their lifecycle, while the snail host would very much prefer not to be eaten, the worms have developed the ability to alter the behavior of their hosts via as-yet-unknown mechanisms. Worm-infected snails become more active and seem to prefer higher, more brightly lit perches, increasing their accessibility to avian predators. To further tempt the birds, the stripey broodsacs begin to pulse rapidly, giving them the characteristic disco-eyed appearance. Scientists think their strange, pulsing eyestalks mimic the movement of a tasty caterpillar. When a bird takes the bait, the parasites take up residence in its gut, mature into adults, and reproduce, beginning the cycle all over again.

"Throughout the book, Weisberger reveals the uncomfortable pervasiveness of this zombie phenomenon: Fruit flies, cicadas, ants, bees, caterpillars, spiders, grasshoppers, and ladybugs can all be victims of these tiny, parasitic puppet masters. “The zombifiers are diverse. The hosts that they zombify are diverse. The mechanisms that they use are very diverse,” said Weisberger. “So individually, all of these examples are really exciting, but together, they also added up to this really interesting picture. Just what is behavior manipulation? Why is this strategy so successful? And why are so many organisms doing it?

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"Because many of these zombifying agents have fine-tuned their manipulation abilities to the point that they specialize in just one type of host, scientists are exploring how they might be used to develop more ecologically-friendly pest control strategies that target crop pests or invasive species, while sparing bees and other insects that provide important ecosystem services.

"The emerald cockroach wasp, Ampulex compressa, hijacks the motor centers of a cockroach brain using specialized peptides in its venom.

"The bioactive compounds produced by zombifying organisms could also be useful in medicine. For example, the emerald cockroach wasp’s venom, which interacts with dopamine receptors in the cockroach brain to influence motor behaviors, could help inspire new treatments for movement disorders such as Parkinson’s disease. And Ophiocordyceps unilateralis, the fungus famous for creating zombie ants, produces secondary metabolites that may influence neurological function in mammals."

Comment: from a book review. These are weird parasitic lifecycles, and one can only wonder as to how they evolve. The review shows how we might medically use the controlling compounds.