Host diversity in hypocrealean invertebrate-pathogenic fungi
Plant Microbe Interaction Research Team, National Center for Genetic Engineering and Biotechnology (BIOTEC), 113 Thailand Science Park, Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand
Invertebrate-pathogenic fungi (IPF) play a vital role in ecological systems by killing millions of tons of invertebrates every year and are thus known to be controllers of insect and spider populations. Ascomycetous invertebrate-pathogens could be found across several ascomycete orders, and the Hypocreales harbors most of them. The number of insect orders varies from 29 to 34 but only about 20 of these orders are infected by fungi. Most of the pathogens could be found on Coleoptera and Lepidoptera species, but they could also be on Hemiptera (scale insects, white files, cicadae, planthoppers), Orthoptera (crickets and grasshoppers), Hymenoptera (ants, bees, wasps), Isoptera (termites), Diptera (flies) and less frequently on Odonata (dragonflies), or Neuroptera, among others. When it comes to spiders (order Araneae, Class Arachnida), only two spider infraorders are known to be parasitized by IPF: the Mygalomorphae and Araneomorphae. Interestingly, IPF can also be found occurring on millepedes and nematodes. High rates of infection have been observed from tropical/subtropical forested areas (including national parks and wildlife sanctuaries) but could also be found in agricultural ecosystems (organic orchards and farms) where the humidity is high. All entomopathogenic fungi are transmitted via spores, and could infect all stages of development: juveniles, eggs, larvae, pupae, nymphs, and adults, resulting in a variety of morphologies.