Mycophagous Mite, Prefers to Feed on Entomopathogenic Fungi, except Generalists.

(1) Background: The mycophagous mite, , was found to feed on entomopathogenic fungi (EPF) in our previous experiments, which seriously impacted the culture and preservation of fungal strains. Therefore, it is necessary to investigate the biological characteristics of the occurrence and damage to EPF. (2) Methods: The mite's growth and development and feeding preference were surveyed by comparative culture and observation; also, optical and electronic microscopies were employed. (3) Results: could survive normally after being fed on seven EPF species, including , , , , , , and . The first four fungi were the mite's favorites with their greater feeding amount and shorter developmental duration. Interestingly, the mite could also feed on and , but this led to the mite's death. After feeding on and , the mites began to die after 24 h, and the mortality rate reached 100% by 72 h. Observation under optical microscopy and scanning electron microscopy revealed that the conidia of and adhered to the mite's surface, but there was no evidence of penetration or invasion. However, dissection observation indicated that the two species germinate and grow within the mite's digestive tract, which implies that generalists with broad-spectrum hosts and the production of destruxins have acaricidal activity toward the mycophagous mites.