Fair warning, people – you absolutely will never be able to unsee this video, no matter how badly you wish you might be able to do just that.
Parasites who take over their hosts’ brains and/or motor function while the creature is still alive are some of the most horrifying villains of the biological world, and…y’all. This diabolical flatworm ranks pretty high on the squick scale.
The flatworm is from the genus Leucochloridium, and its entire goal in life is to produce more of itself.
In order to accomplish that goal, it infects an intermediate host, like the unfortunate snail in the video. While in its larval stage, the worm moves into the hosts eyestalks and head. The larvae vaguely resembles a caterpillar, but it can make itself look much more caterpillar-ish by pulsing, which it does in order to attract the attention of birds.
Because they actually want to be eaten.
The “zombie snail” is driven to spend more time than it normally would in higher and more sunlit spots, making it much more likely to find its way into the stomach of a bird. Research out of Poland suggests that the pulsing like they’re at a dance club really gets going the more light they receive, as well.
Once a bird notices and swallows the snail (or other infected host), the parasite enters adulthood in the bird’s GI tract. The larvae mature and release eggs, which are excreted by the birds and then eaten by snails.
It’s a horrible circle of life.
One that was caught on video in Changhua County, Taiwan, by hiker Lin Ruian. Since then, the footage spread through the internet like flatworms through a snail, and was tweeted by biologist Mike Inouye.
This zombie snail. A parasitic worm Leucochloridium has taken over its motor functions and eye stalks, making them into caterpillar mimics so birds will eat them. The worm can then reproduce in the bird's GI tract, eventually transmitting via its faeces ? https://t.co/mP8IrGh21Lpic.twitter.com/C2xc83oU54