Monthly Archive for September, 2009

Radiolab this week treats the ever fascinating topic of parasites. In the hour long podcast, Jad Abumrad and Robert Krulwich diffuse into the wondrous world of zombie cockroaches and cordyceps ladden ants (really this one is a must see!). Cordyceps is particularly surreal because, of its hundreds of varieties, each has evolved to commandeer the neural functions of a different species in order to hop another link of the biosphere.

See also:

Brainwashed by a neuroparasite

Discover Magazine Gallery – Zombie animals and the parasites that control them

Cymothoa exigua is a parasitic crustacean of the family Cymothoidae. It tends to be 3 to 4 cm long. This parasite attaches itself at the base of the spotted rose snapper’s (Lutjanus guttatus) tongue, entering the fish’s mouth through its gills. It then proceeds to extract blood through the claws on its front three pairs of legs.

As the parasite grows, less and less blood reaches the tongue, and eventually the organ atrophies from lack of blood. The parasite then replaces the fish’s tongue by attaching its own body to the muscles of the tongue stub. The fish is able to use the parasite just like a normal tongue. It appears that the parasite does not cause any other damage to the host fish. Once C. exigua replaces the tongue, some feed on the host’s blood and many others feed on fish mucus. They do not eat scraps of the fish’s food.This is the only known case of a parasite functionally replacing a host organ.

There are many species of Cymothoa, but only C. exigua is known to consume and replace its host’s tongue.

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