Ophiocordyceps is a genus of fungi within the family Ophiocordycipitaceae. The widespread genus, first described scientifically by British mycologist Tom Petch in 1931, contains about 140 species that grow on insects. Anamorphic genera that correspond with Ophiocordyceps species are Hirsutella, Hymenostilbe, Isaria, Paraisaria, and Syngliocladium.
One species complex, Ophiocordyceps unilateralis, is known for its parasitism on ants, in which it alters the behavior of the ants in such a way as to propagate itself more effectively. The parasite starts on the ground and comes in contact with an ant, killing it and then growing its fruiting bodies from the ant's head and releasing its spores.
To accomplish this, infected ants are stripped of their instinctive fear of heights, and leaving the relative safety of their nests, climb up the nearest plant—a syndrome known as "summit disease".
The ant then clamps its jaws around the plant in a "death grip" and mycelia grow from the ant's feet and stitch them to the surface of the plant. The spores released from the ant carcass fall to the ground and infect other ants that come in contact with the spores so that this cycle continues. Areas with high densities of ants that have this fungus growing out of them are known as graveyards.
A 48-million-year-old fossil of an ant in the death-grip of Ophiocordyceps unilateralis was discovered in Germany.
Not all fungi of this genus are harmful to host insects. A few act as yeast-like symbioants of cicadas, having retired from the parasitic lifestyle of O. sobolifera to take on the role of the degraded Hodgkinia (bacterial) symbioant.
Sources and uses
Moth larvae infested by Ophiocordyceps sinensis sold as herbal medicine
Ophiocordyceps sinensis is a species that infects the larvae of Tibetan ghost moths, and is used extensively in traditional Chinese medicine. There is currently no scientific evidence that use of this species has any clinically detectable effect on human diseases....
