[3] It is an ectoparasite of an invasive species to Europe and the Americas,[4] the harlequin ladybird (Harmonia axyridis).

[5] Laboratory bioassays pointed out that Hesperomyces-infected ladybirds suffered increased mortality rates.

[6] The fungus completes its entire life cycle on the tough outer layer or integument of a living host where individual fruiting bodies or thalli are formed directly from ascospores.

The thalli can form on any part of the insect, but spore germination likely only occurs once the host cuticle has hardened.

Due to the spores' sticky nature, they are not transmitted by contact with substrate or the air.