The entomopathogenic fungus Ophiocordyceps sinensis (Berk.) Sung, 2007 (Hypocreales: Ophiocordycipitaceae) parasitizes the larvae of moths in the genus Thitarodes Viette, 1968 (Lepidoptera: Hepialidae). Ophiocordyceps sinensis parasitizes soil-boring Thitarodes larvae: the fungal mycelium proliferates throughout the larval tissues and extrudes a stroma through the head capsule of its host, out of the soil surface to release ascospores. The whole complex hardens into a mummified, caterpillar-shaped bundle of fungal mycelium and stroma commonly referred to as ‘caterpillar fungus’.

This moth–fungus symbiont was first described in the 15th century by Tibetan scholars and has since been avidly collected in its endemic range by Chinese and Tibetans as an ethnomedicine [1]. Accounts from the eighteenth century suggest already well-established trade routes from historical Tibet to coastal China [2,3]. Present-day demand for caterpillar fungus from mainland China has been known to drive its price up to more than three times that of gold [4]. The collection of caterpillar fungus from the wild generates the primary source of income for hundreds of thousands of collectors [5]. Conservative estimates place annual production of dried caterpillar fungus at 100 tons [6], amounting to 300 million individual caterpillar fungi collected per year at a market value of $5–11 billion [7]. Intense territorial conflicts over land ownership and collection rights have arisen across the Himalaya and the Tibetan Plateau, the range of caterpillar fungus [8]. Such conflicts will persist as suitable habitats continue to shift and decrease due to climate change [9–11].