Ophiocordyceps Sinensis - Natural History

Natural History

The caterpillars prone to infection by the fungus which live underground in alpine grass and shrublands on the Tibetan Plateau and the Himalayas at an altitude between 3,000 and 5,000 m (9,800 and 16,000 ft). Spending up to five years underground before pupating, the Thitarodes caterpillar is attacked while feeding on roots. It is not certain how the fungus infects the caterpillar; possibly by ingestion of a fungal spore or by the fungus mycelium invading the insect through one of the insect's breathing pores. The fungus invades the body of the caterpillars, filling its entire body cavity with mycelia, a sclerotium and eventually killing and mummifying the host. The caterpillars die near the tops of their burrows. The dark brown to black fruiting body (or mushroom) emerges from the ground in spring or early summer, always growing out of the forehead of the caterpillar. The long, usually columnar fruiting body reaches 5–15 cm above the surface and releases spores.

In Nepal caterpillar fungus is found on the subalpine pastures in Dolpa in Karnali Zone and Darchula in Mahakali zone. It is also common in Bhutan and India's Himachal Pradesh and Uttarakhand Himalayas. Reports of distribution outside of "High Asia" are erroneous and relate to species of Cordyceps, e.g. Cordyceps militaris.