Wildlife
Cordyceps are a group of parasitic fungi containing over 400 described species. Their hosts are ususally insects but they can also infect other fungi. One species parasitizes ants and can change its victim's behaviour. The cordyceps impels the ant to climb up a stem where it dies. From this elevated vantage point the fungus's fruiting body grows out of the victim's body, allowing the spores to be more widely distributed by the wind. Some species, such as the caterpillar fungus, are considered to have medicinal properties in China and Tibet.
Scientific name: Cordyceps
Rank: Genus
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Fungal brew
Steve Backshall gets a taste of the local mountain medicine.
Steve Backshall gets a taste of the local mountain medicine.
Bad headache!
A parasitic fungus sends ants over the top.
In the forests of Papua New Guinea, fungal spores infect ants and compel them to crawl upwards and glue themselves to the undersides of leaves. With the ant glued in place, the fungus continues to grow and uses the ants body as food, eventually forcing a stalk with spore sacs through the ant's head, before exploding to shed more spores throughout the forest.
Parasitic fungi attack
The parasitic cordyceps sends its victims mad before erupting from their bodies.
At a quick glance, the ants and other insects in this clip seem to be suffering from a science fiction affliction. Imagine a fungus which lodges itself inside you, compels you to climb as high as you can and then explodes out of your body, killing you in the process. But this is no alien encounter or April fool - there are literally thosands of different types of cordyceps fungus, each specialising on just one species. They are so virulent, this killer can wipe out whole colonies of ants!
Cordyceps is a genus of ascomycete fungi (sac fungi) that includes about 400 described species. All Cordyceps species are endoparasitoids, mainly on insects and other arthropods (they are thus entomopathogenic fungi); a few are parasitic on other fungi. The best known species of the genus is Cordyceps sinensis, first recorded as yartsa gunbu in Tibet in the 15th Century. It is known as yarsha gumba in Nepal. The Latin etymology describes cord as club, ceps as head, and sinensis as Chinese. Cordyceps sinensis, known in English commonly as caterpillar fungus, is considered a medicinal mushroom in oriental medicines, such as traditional Chinese medicines[unreliable source?] and traditional Tibetan medicine.
When a Cordyceps fungus attacks a host, the mycelium invades and eventually replaces the host tissue, while the elongated fruiting body (ascocarp) may be cylindrical, branched, or of complex shape. The ascocarp bears many small, flask-shaped perithecia containing asci. These in turn contain thread-like ascospores, which usually break into fragments and are presumably infective.
Some Cordyceps species are able to affect the behavior of their insect host: Cordyceps unilateralis causes ants to climb a plant and attach there before they die. This ensures the parasite's environment is at an optimal temperature and humidity and maximal distribution of the spores from the fruiting body that sprouts out of the dead insect is achieved. Marks have been found on fossilised leaves which suggest this ability to modify the host's behaviour evolved more than 48 million years ago.
The genus has a worldwide distribution and most of the approximately 400 species have been described from Asia (notably Nepal, China, Japan, Korea, Vietnam and Thailand). Cordyceps species are particularly abundant and diverse in humid temperate and tropical forests.
The genus has many anamorphs (asexual states), of which Beauveria (possibly including Beauveria bassiana, Metarhizium, and Isaria) are the better known, since these have been used in biological control of insect pests.
Some Cordyceps species are sources of biochemicals with interesting biological and pharmacological properties, like cordycepin; the anamorph of Cordyceps subsessilis (Tolypocladium inflatum) was the source of ciclosporin—a drug helpful in human organ transplants, as it suppresses the immune system (Immunosuppressive drug).
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