Locust (Locusta migratoria) killed by the fungus Metarhizium acridum. The green coloured spores are produced on the mycosed insect.
Dead housefly (Musca domestica) killed by the fungus Entomophthora muscae that is growing out from the abdomen to actively discharge infective spores.
Theoretical overview of the three stages involved in pathogenic host shifts. A pathogen of the red fly comes into contact with a new host species (black flies). If the pathogen is unable to continue transmission in the new host it will die, here denoted by a black cross. Different ecological and evolutionary factors are involved at the three stages. Figure is inspired Mollentze et al. 2014, Curr. Op. Virol. 8:68-72.