Cordyceps

Cordyceps are one of many "insect pathogenic fungi” and are fascinating organisms despite the bad rap they get from tabloids and the click-bait websites which regularly feature stories about "zombie fungus”.

The photos on this page show various entomopathogenic fungi and some of them are cordyceps species. The problem I have is that identifying them with certainty requires expert knowledge which I don’t have. It is very tricky.

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

It is relatively easy to find insects that have been infected by an entomopathogenic fungus in both temperate and tropical forests. I find them frequently as I scan the undersides of leaves, the tops of tall grasses and the bark of trees for insects.

Those locations are favored by cordyceps which may compel its host to crawl up trees or grasses. Once the host expires and the fungus has matured it will eject spores — the extra altitude presumably helps them disperse more effectively and alight on new hosts.

I have found moths, flies, crickets, ants, beetles, and spiders that I’m pretty certain were infected by cordyceps -- and each was likely infected by a different cordyceps species.

Here’s how the life cycle works: A microscopic cordyceps spore lands on an insect. The spore develops and a web-like structure (mycelium) grows inside the insect. This does not necessarily kill the insect immediately but will absorb nutrients from the insect. The cordyceps will eventually send up one or more columns that will emerge from the insect and eventually eject spores. The insect dies in the process but may remain alive and partially paralyzed as the fungus matures inside it.

As far as I can tell, all entomopathogenic fungi reproduce using spores.

In these photos, you'll see a variety of moths, ants, spiders, flies and other insects who are shrouded (pun intended) by a fungus -- I suspect that those with spires are cordyceps but I am not certain. If you can ID any of these, I'd love to hear from you!

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 or so.


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