The caterpillar fungus, Ophiocordyceps sinensis, is a close relative of more well known “zombie-ant” fungus, Ophiocordyceps unilateralis. Similar to it’s cousin, the “zombie-ant” fungus, O. sinesis does infect insects – the larval stage of the ghost moth, Hepialus humuli. However, instead of producing compounds to infect and modify insect brains, the caterpillar fungus is known to produce compounds with medicinal, aphrodisiac, and athletic enhancing properties in humans. These enhancing effects have never been classically tested in clinical trials, but many people throughout the region swear by its immune-building benefits. Because of these touted benefits, the caterpillar fungus has been called the most valuable parasite in the world, being used in self-medication, sports doping, and bribes, and is worth three times its weight in gold in Beijing (Yong, 2018). It gained popularity in the news as the “Himalayan Viagra” (Kotamraju, 2016), and is indeed limited in its global distribution and can only be found in the Himalaya plateaus.
Unfortunately, a trifecta of problems is causing the valuable fungus to disappear; a limited distribution, over-harvesting, and a warming climate (Hopping et al. 2018). Both the caterpillar fungus and the ghost moth are adapted to cold, dry conditions at high elevations, and global climate trends are making these types of regions to increase in temperature and humidity, making it difficult for the fungus and moth to survive. Some countries in the region are beginning to place harvest limits on the caterpillar fungi, but they are so valuable that many natives to the region rely on it for their primary source of income, making it difficult to stop over-harvesting.
Yong, E. The Worlds Most Valuable Parasite is in Trouble. The Atlantic. 2018. (https://www.theatlantic.com/science/archive/2018/10/tibetan-caterpillar-fungus-trouble/573607/)
Kotamraju, G. Yartsa gunbu (Ophiocordyceps sinensis) – Entomopathogen nicknamed Himalayan Viagra. Bonito Lab – Fungi in the News. 2016. (https://bonito.psm.msu.edu/2016/11/yartsa-gunbu-ophiocordyceps-sinensis-entomopathogen-nicknamed-himalayan-viagra/)
Hopping, K. A. et al. The demise of caterpillar fungus in the Himalayan region due to climate change and overharvesting. PNAS. 2018. www.pnas.org/cgi/doi/10.1073/pnas.181159111510.30.18