Parasite living inside fish eyeball controls its behavior
By Elizabeth Preston
A COMMON PARASITE that lives in fish eyeballs seems to be a driver behind the fish’s behavior, pulling the strings from inside its eyes.
When the parasite is young, it helps its host stay safe from predators. But once the parasite matures, it does everything it can to get that fish eaten by a bird and so continue its life cycle.
The eye fluke Diplostomum pseudospathaceum has a life cycle that takes place in three different types of animal. First, parasites mate in a bird’s digestive tract, shedding their eggs in its feces. The eggs hatch in the water into larvae that seek out freshwater snails to infect.
They grow and multiply inside the snails before being released into the water, ready to track down their next host: fish. The parasites then penetrate the skin of fish, and travel to the lens of the eye to hide out and grow.
The fish then get eaten by a bird –- and the cycle starts again.
Many parasites can change an animal’s behavior to fit their own needs. Mice infected with the parasite Toxoplasma gondii, for example, lose their fear of cats, the animal the parasite needs to reproduce inside.
https://www.newscientist.com/article/21 ... 1493921038
This is disturbing, not to mention disgusting.
What parasites might we have living somewhere in our heads (or maybe some other parts of our bodies) that are calling the shots, while we're thinking what we do is all OUR idea?