Parasitic Caterpillar Fungus (Ophiocordyceps sinensis) Ophiocordyceps sinensis, known as caterpillar fungus. The fungus is known in Tibetan as yartsa gunbu or yatsa gunbu. Caterpillar fungi are the result of a parasitic relationship between the fungus and the larva of the ghost moth genus Thitarodes, several species of which live on the Tibetan Plateau, China, the Himalayas, India, Nepal, and Bhutan. The fungus germinates in the caterpillar larvae, eventually killing the host and producing the fruiting body of the fungus from the body of the insect. O. sinensis is known as a medicinal mushroom, and its use has a long history in Traditional Chinese medicine. The hand-collected fungus-caterpillar combination is valued by herbalists and as a status symbol. It is used as an aphrodisiac and treatment for ailments such as fatigue and cancer. Clinical trials have not established any efficacy. Due to recent demand, the current price as of 2012 the infected caterpillar is worth more than gold per gram.