Natures wonders: zombified animals (Introduction)

by David Turell , Tuesday, January 10, 2017, 01:10 (2656 days ago) @ David Turell

Zombification is a very common event:

http://www.livescience.com/34196-zombie-animals.html?utm_source=ls-newsletter&utm_m...

Victim: pill bug

"Roly-poly bugs, potato bugs, pill bugs: they're cute and innocuous members of the insect world, right? Sure as long as they haven't been taken over by a nefarious acanthocephalon (Plagiorhynchus cylindraceus) parasite. The parasite lives in the intestinal tract of birds called starlings, and gets pooped out right into the waiting jaws of the pill bug. (Pill bugs relish bird poop.) Once inside the body of the oblivious roly-poly, the parasite takes over its brain and urges the zombified bug to do crazy things, such as making its whereabouts widely known to its predator, the starling. And thus the parasite completes its journey and runs off to find another bug upon which to practice mind control.

Victim: cockroach

"It's straight out of Hollywood: A quick stab to the brain turns an innocent onlooker into the victim of a brutal assault and kidnapping. Except this time, that defenseless victim is one of the world's most hated insects (the cockroach) and the villain is a wasp. In this true story, the wasp's venom renders the cockroach unable to move. After being dragged into the wasp's lair, the cockroach continues to live even though its abdomen is being implanted with the wasp's eggs. The larva later hatches and eats the still living but incapacitated cockroach from the inside out. A month later, the mature wasp flies away from the scene of the crime, leaving only a rotting carcass behind.

Victim: ant

"Zombie discoveries are happening all the time. Just this year, scientists discovered four new types of body-snatching fungi that prey on carpenter ants. The fungus infects the ants and then begins to use chemical signals to direct the ant on a very strange path. The zombified ant then leaves its colony and takes a jaw-grip on the underside of a leaf, where it stays. When it eventually dies as the fungus spreads around the ant's body, the fungus produces a stalk from the dead zombie's head and shoots spores out, trying to lure other ants to join the party.

Victim: crab

"It's a story of crab-meets-barnacle, with a twist. A female Sacculina barnacle wants to nest inside a crab, so it looks around for a place to get in and when it does, it leaves that nasty old barnacle body behind. Once inside, the barnacle makes a nice little home that looks like a tumor, extending tendrils through the crab's body and slowly eating its host. After killing the sex organs of its new abode, the barnacle makes the home become the babysitter. As the crab loses interest in anything but serving its zombie overlord, the barnacle bores a hole in the crab's shell and invites willing males to come and mate. Hey, the babies are going to be well-looked-after in a cozy home.

Victim: spider

"The poor Plesiometa argyra. A Costa Rican spider just looking to catch some bugs can be taken over by a parasitic wasp that plants its larvae inside the spider's body, along with a new blueprint. Instead of building its web, the spider spends the last night of its life constructing a silk cocoon, which becomes a home for its killers. When the silk sack is done, the larvae kill the spider. Then they take up residence in the cocoon, suspended safely above the predators of the rainforest floor. That's some gratitude! "

Comment: Neat tricks, but there is no way these lifestyles could have developed stepwise. Especially if the system involves a third party like the starling and Pill bug. Or a zombie ant that has to find a certain leaf to clamp onto. The only answer is saltation.