Why are there so few examples of entomopathogenic fungi that manipulate host sexual behaviors

Abstract

Abstract For entomopathogenic fungi (EPF), it may be particularly advantageous to manipulate host behavior in order to increase conspecific encounters that facilitate transmission of conidia. To achieve this, some EPF apparently alter the chemical communication and signaling of insect sexual behavior, but there are very few documented examples. Here, we identify and discuss the few known examples and propose two categories of EPF-induced alterations in insect sexual behavior. First, EPF may induce changes in how healthy conspecifics of the opposite sex perceive and respond to the infected individual via chemical or visual cues, which promote the display of sexual behaviors towards the infected individual. Second, EPF may directly change sexual behavior of the infected individual to promote conspecific encounters. We conclude that the scarcity of observed examples is likely caused by the difficulty of detecting subtle changes in insect sexual behavior, but also because manipulation of host sexual behavior is a trait primarily present in understudied host-specific EPF.