– a parasite introduced from the tropics and found in the salt marshes of southern California. The parasite'
s eggs enter the water with the waders'
droppings, where they are eaten by Cerithideopsis californica snails. The snails become sterile. Several generations develop inside the snail, and then the cercariae larvae emerge into the water. The larvae attach to the gills of the Killifish (order Carpozoa) and work their way along the nerves into the cranial cavity where they build up a carpet around the brain. Infested fish are four times more likely to “wiggle, twitch, shimmy and show themselves” (Lafferty, K. D. (1999). “The evolution of trophic transmission.”) than uninfected ones. This behaviour increases their likelihood of being caught and eaten by birds by more than 30 times. The parasite then lives in the intestines of the birds and produces eggs, which are released with the droppings and enter the water body. (translation from English Wikipedia article