Zombies schmombies. Let's talk parasites.

We here at Zooillogix balked at the idea of 'Zombie day' on ScienceBlogs (and secretly loved it, too). What better example than the animal world to show TRUE zombie-ism at its best?

Parasites.

Need I even say more? We've posted and posted again and posted another time about zombies before this day of celebration. But in honor of the day, we have found a few more interesting parasite zombie stories to share with your children when they are misbehaving.

Pillbugs. Potato bugs. Rolly pollies. Don't we all remember these little innocuous guys? But did you know they could be zombified?! The acanthocephalon (Plagiorhynchus cylindraceus) is a parasite that lives in the intestinal tract of starlings. That's right- birds. They don't cause any harm to the bird; they just use its gut as an SRO. A self-cleaning SRO that flushes the parasite eggs out with the bird's feces.

Pillbugs love them some feces. When they happen upon a pile of steaming yumminess, they strap on their bibs and feast. Now inside the pillbug, the parasite egg hatches and quickly takes control. While all its natural instincts would be to stay in dark shelter, the zombified pillbug sets out on a suicidal journey, making itself easily visible to predators. Predators such as starlings. Zombifying parasites are wicked smart!

Let's take another example. The sweet little snail. Who wants to victimize a snail besides small boys with canisters of salt? How about the flatworm, Leucochloridium paradoxum? This flatworm, like P. cylindraceus, needs a bird to complete its life cycle. The larvae of the worm are excreted in bird feces, which are a delicacy to pillbugs and snails alike. Inside the snail, the larvae develop into sporocysts, which grow into long structures called broodsacs. These broodsacs then invade the antennae of the snail, transforming the once thin eye-stalks into swollen, colorful, pulsating grub-like appendages. To add insult to injury (or salt to the wound, I suppose), this transformation results in a reduced sensitivity to light, causing the snail to wonder about in plain view of avian predators. (On a side note, the meth test on these snails produced entirely different results.)

Ladies and gentlemen, I give you exhibit A....

Would you like one more? Wasps of the genus Glyptapanteles enslave caterpillars to not only be a host for their growing eggs, but to be a body guard for them while they are in cocoon! The wasp injects the unsuspecting caterpillar with its eggs, which then hatch and dine on caterpillar guts. Once they have fully developed, they eat their way through the caterpillar's skin, attach to a nearby branch, and spin themselves a cocoon.

You'd think it'd be lights out for the poor caterpillar, now missing some guts and skin. But the wasp isn't done using it, yet. Once the larvae have exited and formed cocoons, the caterpillar sticks around, standing guard over the vulnerable larvae. It forgoes any semblance of regular activity, even giving up eating, in order to ensure would-be predators are not able to get to the cocoons. Eventually, the larvae hatch and the caterpillar finally gives up the ghost. Scientists aren't entirely sure how the wasp manages this mind control, but zombifiers across the globe could learn a lesson or two from it. Check out this video...

And with that, Zooillogix wraps up our participation in Zombie Day. Keep the challenges coming, ScienceBlogs! We love it!