We’ve known for some time about the existence of zombie crabs – crustaceans that have been taken over by an invasive parasite and turned into mindless living incubators for baby parasites. It sounded harmless and probably inspired a few movies but a new study has found that these zombie crabs are creating havoc in the ecosystem off the coast of South Carolina.
Blaine D. Griffen, Associate Professor in the Biological Sciences and the Marine Sciences Program at the University of South Carolina, headed the research. The waters off the coast of South Carolina are populated with flatback mud crabs (Eurypanopeus depressus). Like many other crab species, the flatbacks have been attacked by Sacculina carcini – a parasitic rhizocephala or barnacle, in this case the Loxothylacus panopei. The barnacle larvae attacks the crab at the base of a hair or setae and injects itself into the bloodstream, where it grows inside the crab with its female reproductive organ protruding from the crab’s abdomen. The Sacculina then castrates the crab, completing the takeover of its insides, mind and body – creating the zombie crab.
Normal mud crabs feed constantly and voraciously on mussels, keeping the population manageable. According to Griffen, zombie crabs lose their appetites for mussels, eating only one a day. His researchers found that about a fifth of the crabs off the coast were infected with L. panopei.
While fans of mussels may rejoice in their increased numbers, any upset in the delicate balance of an ecosystem is a cause for concern because it also affects the creatures who prey on these species. For evidence, consider the parasite that changes shrimp from male to female that has wreaked havoc to the commercial mussel and oyster bed operations in the UK.
Are we preparing for the wrong zombie apocalypse?