The intricate dance: Exploring the interactions between entomopathogenic fungi and insects with special focus on the formation/production of Chinese cordyceps

Entomopathogenic fungi (EPF) represent a specialized group of microorganisms which are distinguished by their ability to infect and kill arthropods. Ophiocordyceps sinensis, a well-known and highly valued EPF species, infects the soil-dwelling larvae of Thitarodes/Hepialus (ghost moths) on the Tibetan Plateau. After the mummification of ghost moth larvae, the fungus-insect parasite complex with a fruiting body is known as Chinese cordyceps. This complex is highly esteemed as one of the most valuable traditional Asian medicines. Notably, the ghost moth larvae can survive several months after infection with O. sinensis, which makes it an exceptional model for gaining insight into the complex mechanisms in the production of Chinese cordyceps. In this review we discussed the interactions of important EPF with some key insects. Specifically, we summarized the mechanisms of EPF's mode of entry and action, uncovering the intriguing processes behind their pathogenicity. We further discussed the influence of fungal toxins on insect physiology and development, revealing the multifaceted effects that result in host mortality. Moreover, we summarized the interaction of EPF with insect's microbiota, revealing the complex dynamics that impact the pathogenic process. However, our primary focus remains on the interaction of O. sinensis with the ghost moth. Such understandings will further improve our knowledge of this complex interplay between O. sinensis and ghost moth, ultimately contributing to the improvement of Chinese cordyceps production.