Cordyceps and Entomopathogenic fungi

  • Infected fly, Virginia

    Infected fly, Virginia

    Cordyceps is a 600-species strong genus of fungi that includes a large number of insect pathogenic fungi. These are fungi that infect an insect, feed from it while growing, and ultimately kill it.

  • Fruiting bodies of entomopathogenic fungi, Virginia.

    Fruiting bodies of entomopathogenic fungi, Virginia.

    In this photo, the body of the fungus (mycelium) has enveloped the host and spore-producing structures have formed. Not much is left of the insect which may be a cricket or grasshopper.

  • Spider, Virginia.

    Spider, Virginia.

    Another shot showing the fruiting bodies beginning to form.

  • Close up of fruiting bodies, Costa Rica

    Close up of fruiting bodies, Costa Rica

  • Moth, Virginia.

    Moth, Virginia.

    Once the mycelium has enveloped the host the result is a mass that's durable and firm to the touch.

  • Robber fly (Asilidae), Singapore.

    Robber fly (Asilidae), Singapore.

  • Unidentified host and fungus, Peru.

    Unidentified host and fungus, Peru.

  • Harvestman (Opiliones), Virginia.

    Harvestman (Opiliones), Virginia.

  • Caterpillar, Peru.

    Caterpillar, Peru.

    Likely an entomopathogenic fungus but probably not a cordyceps.

  • Moth, Peru.

    Moth, Peru.

    Moths, flies, crickets, ants, beetles, and spiders are all targeted by cordyceps species. Each host species is usually infected by a specific cordyceps species which can only use a specific species as a host.

  • Spider


  • Spider, Virginia.

    Spider, Virginia.

    Cordyceps are all “Ascomycota” or "sac fungi”, a large division of the fungi kingdom defined by their reproductive trait of ejecting spores. Ascomycota includes the extraordinarily tasty morel, the yeast we use to brew beer, penicillin, and the pretty cup fungi we find in temperate and tropical forests.

  • Spider, Virginia.

    Spider, Virginia.

    In this photo, the mycelium has enveloped the host and spore producing structures are forming.

  • Fly, Virginia.

    Fly, Virginia.

    The many species of entomopathogenic fungi have a variety of forms. This is the one I most frequently see consuming flies in Virginia.

  • Fruiting bodies, Costa Rica.

    Fruiting bodies, Costa Rica.

  • Spider, Virginia.

    Spider, Virginia.

    Click-bait articles love to dwell on the “zombie fungus” aspect of cordyceps. This is the ability of some cordyceps species to force their host to climb to a relatively high elevation such as the tip of tall grass and then cling to it.

  • Fly, Peruvian Amazon.

    Fly, Peruvian Amazon.

  • Spider, Peru.

    Spider, Peru.

    One cordyceps species is able to force the host’s abdomen to rupture while somehow also keeping the host alive. This is pretty ghastly but, again, it benefits the fungus in terms of spore dispersal.

  • Fly, Virginia.

    Fly, Virginia.

    Another species of cordyceps is able to trick its host's wing muscles into flexing. It is thought that the spreading or dropping of wings allows better spore dispersal.

  • Leaf hopper, Singapore.

    Leaf hopper, Singapore.

  • Ant, Florida.

    Ant, Florida.

    For the curious, infected insects are easy to find in both North America and Central America. On trails where there are edge plants and low-hanging branches, I’d expect to find one every 30 minutes. Look under leaves and on leaf tips.

  • Ant, Peru

    Ant, Peru

  • Scale insect, Virginia.

    Scale insect, Virginia.

    The photos on this section of the site show various entomopathogenic fungi and cordyceps species. Identifying these species with any level of certainty requires expert knowledge which I don’t have. I've identified the host (where possible) using the common name.

  • Infected spider, Virginia

    Infected spider, Virginia

    The tiny creature in the foreground may be a bark louse. Chances are any spore released from the infected spider in the background will only be able to grow on a spider in the same genus as the host. The bark louse is therefore safe.

  • Fruiting bodies, Costa Rica

    Fruiting bodies, Costa Rica

    This close-up shows the elegant and delicate spires from which spores are released by this Costa Rican species of fungus.

  • Moth, Costa Rica.

    Moth, Costa Rica.

  • Spider, Virginia.

    Spider, Virginia.

    The explanation scientists offer for the climbing behavior is that when a fungus releases a spore from a high place the spore is likely to disburse further than if released from a low place. Better dispersion means more spores are likely to find the hosts they need. Natural selection takes care of the rest.

  • Ant, Peru.

    Ant, Peru.

    Entomopathogenic fungi species have evolved multiple tricks to help with dispersal. For example, infected ants and wasps are typically found clamped onto twigs or leaves with their mandibles. Because they are attached to the twig (like the ant in the photo) they will not fall off when they die. This obviously assists the fungi. which needs time for the fruiting body to form and begin disbursing spores. Researchers believe chemical signals created by the cordyceps force this type of behavior on its host

  • Ant, Peru.

    Ant, Peru.

  • Harvestman (Opiliones), Virginia.

    Harvestman (Opiliones), Virginia.

  • Leaf hopper, Peru.

    Leaf hopper, Peru.

    If you would like to read more there is an excellent article which you can find with the search terms: ASM Mechanisms behind the Madness Entomopathogens

  • Spider, Costa Rica

    Spider, Costa Rica

    Remember that these photographs are copyrighted. You may not use them without permission. If you don’t obtain my permission you are stealing. To purchase the right to publish my photos contact me at: I’ll supply hi-resolution files at a very reasonable cost. If you are a scientist, researcher, student, or conservation professional, I’ll be happy to let you use them at no charge — but you still need to get my permission. Simply email me at

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