Figure 1:
Phylogenetic positions of insect pathogenic fungi. (A) The Kingdom Fungi, with emphasis on phyla with insect pathogens. The numbers represent the approximate number of species described within each (sub)phylum and the shading in ten units in the boxes represents the relative proportions of known species of insect pathogens (highest proportion when blue color is darker). Light grey, black and dark grey dots mark the branches with the most common and best-known insect pathogens. (B) Ascomycota have the highest number of described species and the greatest diversity, including a variety of saprophytic, mutualistic and pathogenic life forms. The thick lines represent orders with insect pathogenic fungi and light grey, black and dark grey dots mark those with the most known insect pathogens: Hypocreales (dark grey, for example, Cordyceps sensulato, Metarhizium and Beauveria) and Onygenales (black, Ascosphaera) (HIBBETT et al., 2007HIBBETT, D.S.; BINDER, M.; BISCHOFF, J.F.; BLACKWELL, M.; CANNON, P.F. A higher-level phylogenetic classification of the Fungi. Mycological Research, v.111, p.509-47, 2007.; JAMES et al., 2006JAMES, T.Y.; KAUFF, F.; SCHOCH, C.L.; MATHENY, P.B.; HOFSTETTER, V. Reconstructing the early evolution of Fungi using a six-gene phylogeny. Nature, v.443, p.818-822, 2006.; WHITE et al., 2006WHITE, M.M.; JAMES, T.Y.; O’DONNELL, K.; CAFARO, M.J.; TANABE, Y.; SUGIYAMA, J. Phylogeny of the Zygomycota based on nuclear ribosomal sequence data. Mycology, v.98, p.872-84, 2006.).
Figure 2:
The diagram illustrates the ways in which pathogenic fungi infect arthropod hosts by asexual or sex spores, proliferate and disperse. (A) Infection: Entomophthorales fungi infect mainly by large, sticky conidia that penetrate the cuticle directly, and Hypocreales fungi infect by small conidia, which produce appressorial structures. Ascosphaera spores are also small, enter orally, and infect through the gut epithelium. (B) Growth: most of Hypocreales and Onygenales proliferate through hyphal growth, and Entomophthorales fungi proliferate through protoplasts. (C) Reproduction: asexual conidia of Entomophthorales fungi and sexual ascospores of the Hypocreales are mainly forcibly discharged from the surface of cadavers (arrows upwards to the right), whereas (very large and thick-walled) sexual resting spores of Entomophthorales fungi and asexual conidia of Hypocreales are passively released (upward and downward arrows to the left). Ascosphaera produces only sexual spores that are passively released (downward arrow to the right) (BOOMSMA et al., 2014BOOMSMA, J.; JENSEN, A.; MEYLING, N.; EILENBERG, J. Evolutionary interaction networks of insect pathogenic fungi. Environmental Entomology, v.59, p.467-485, 2014.).
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