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Cordyceps is a genus of ascomycete fungi (sac fungi) that includes over 260 species worldwide, many of which are parasitic. Diverse variants of cordyceps have had more than 1,500 years of use in Chinese medicine. Most Cordyceps species are endoparasitoids, parasitic mainly on insects and other (they are thus entomopathogenic fungi); a few are parasitic on other fungi.
The generic name Cordyceps is derived from the ancient Greek κορδύλη kordýlē, meaning "club", and the Latin language -ceps, derived from Latin caput, meaning "head". The genus has a worldwide distribution, with most of the known species being from Asia.
Cordyceps sensu stricto are the of several genera of anamorphic, entomopathogenic fungi such as Beauveria ( Cordyceps bassiana), Septofusidium, and Lecanicillium.
Cordyceps subgen. Ophiocordyceps was at one time a subgenus defined by morphology. Nuclear DNA sampling done in 2007 shows that members, including "C. sinensis" and "C. unilateralis", as well as some others not placed in the subgenus, were distantly related to most of the remainder of species then placed in Cordyceps (e.g. the type species C. militaris). As a result, it became its own genus, absorbing new members.
The 2007 study also peeled off Metacordyceps (anamorph Metarhizium, Pochonia) and Elaphocordyceps. A number of species remain unclearly assigned and provisionally retained in Cordyceps sensu lato.
Other important anamorphic genera closely allied to Cordyceps sensu stricto include Evlachovaea, Lecanicillium and Beauveria. Dai et al. (2016) concludes their article on the phylogeny of Isaria with the following commentary on future nomenclature under "one fungus one name" (original in Chinese):
The Last of Us proceeds from the premise that a new species of Cordyceps manages to jump the species barrier, from nonhuman to human, as diseases like influenza and viruses like Ebola and COVID-19 have done. Its human hosts initially become violent "infected" beings, before turning into blind zombie "clickers", complete with fungal "fruiting bodies sprouting from their faces". In a detail that reflects Cordyceps biology, "clickers" then seek out a dark place in which to die and release the fungal spores, enabling the parasite to complete its life cycle. Scientific American comments that by combining a plausible mechanism with effective artistic design, the series gains "both scientific rigor and beauty".
In similar vein, Cordyceps causes a pandemic that wipes out most of humanity in Mike Carey's 2014 postapocalyptic novel The Girl with All the Gifts and its 2016 film adaptation. In this case, an infected person becomes a "hungry", a zombie thirsting for blood. In the fiction, Dr. Caldwell explains that the human-infecting fungus is a mutated form of Ophiocordyceps unilateralis (a group of species now split off from Cordyceps) which alters the behaviour of infected insects. The children of infected mothers, however, become "hybrids" with antibodies protecting them against the fungus.
Splits
Cordyceps subgen. Epichloe was at one time a subgenus, but is now regarded as a separate genus, Epichloë.
Selected species
There are over 260 species in the genus Cordyceps including the following species:
Anamorphic genera
Isaria is a genus name that has been applied to many anamorphs of Cordyceps species. This genus itself is treated as a synonym of Cordyceps in Species Fungorum following the "one fungus one name" change, but many species names with Isaria are still preferred by Species Fungorum over the synonyms in other genera (e.g. Isaria sinclarii is preferred over Cordyceps sinclairii). Though confusing, this does match the "equal footing for priority" approach of the "one fungus one name" concept. To add to the complexity, Isaria is a conserved name with a conserved type. What remains under Isaria as of 2016 remains polyphyletic and can be divided into three main clades.
Biology
When Cordyceps attacks a host, the mycelium invades and eventually replaces the host tissue, while the elongated fruit body (ascocarp) may be cylindrical, branched, or of complex shape. The ascocarp bears many small, flask-shaped perithecia containing Ascus. These, in turn, contain thread-like ascospores, which usually break into fragments and are presumably infective.
Research
Polysaccharide components and the nucleoside cordycepin isolated from C. militaris are under basic research, but more advanced clinical research has been limited and too low in quality to identify any therapeutic potential of cordyceps components.
Uses
Cordyceps sensu lato (which now includes Ophiocordyceps and many other genera holding species originally in this genus) has long been used in traditional Chinese medicine in the belief it can be used to treat diseases. There is no strong Science evidence for such uses.
Cultural representations
The video game series The Last of Us (2013– ) and its television adaptation present Cordyceps as a deadly threat to the human race, its parasitism powerful enough to result in global calamity. The result is a zombie apocalypse and the collapse of human civilization. Scientific American notes that some species in the genus "are indeed body snatchers–they have been making real zombies for millions of years", though of ants or , not of humans.
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See also
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