Gastropod meets Leucochloridium paradoxum parasite. The snail's appendages have seen better days. Photo: Thomas Hahmann

When Bugs Go Bad—Really Bad. Talk about uncomfortable relationships: Scientific American brings us up close and personal with several hair-raising tales of parasites in the animal kingdom, including a flatworm that multiplies inside snails. Once the worms are ready to trade up on a host:

"[They] push up into the snail's tentacles, making them swell and squirm, mimicking the action of bugs that birds like to eat. As the snail crawls, blindly, into the sunlight, a passing bird is likely to swoop down to snatch a tasty tentacle or two."

The worms return to terra firma to infect other unsuspecting gastropods courtesy of bird droppings.

The puppeteers profiled drive their hosts to all manner of slavish behavior: the hosts find themselves diving into certain death, having their innards offered up in a leisurely buffet to the parasite young, and acting as the ultimate nanny.

Lest you think we are safe from any persuasions of this sort, think again:

The chemical changes brought on by the parasite [Toxoplasma gondii] appear to have some of the same effects on humans, who can be infected by ingesting parasite eggs from cat feces. Research by Kevin Lafferty, a research ecologist with the U.S. Geological Survey, has found that the parasite can cause women to act more moralistically, and men less so.

For the full stories, read the Scientific American article. Then check out their accompanying slideshow for more gruesome features.

Earthjustice wishes you a happy Halloween!

More Reads:
In Rotterdam, Webs of Mystery, National Geographic
The Invasion of the Budgies, ABC News (photo series by Ann Britton)
Don't try this at home: Bears 'are not violent and do not like honey', Telegraph.co.uk
The Secret History of the Swine Flu, New Scientist