Let Them Eat Mushrooms

The fifth, and final installment, celebrating the Week of the Fungi on STC. Bon appetit!

by Elio

People who venture into forests in search of mushrooms have insects to contend with. I don't mean mosquitoes, wasps, and bees. I mean bugs that enjoy eating mushrooms at least as much as some of us do. Mushroom hunting is a chancy enterprise at best. But as if that weren't enough, sometimes we come upon a fine specimen of a delectable species, only to find it rendered inedible by insects who got there first. Often we find them riddled with tunnels made by the larvae of fungus gnats that had deposited their eggs in the mushrooms. Some mushroom hunters call these mushrooms “wormy” and joke about their extra protein content. Some joke!

A Pleurotus sp. (oyster mushroom) 10 cm across was placed 1 m
from a colony of E. procera. It didn't take long…

If you watch nature shows on TV, you will know that insects and fungi have numerous, very close connections. Likewise, if you have been reading this blog, you might recall when we brought this up ourselves. But here we're talking about a particular sort of interaction: mycogastronomy.

You probably know already that one group of ants, the leafcutters, dine on fungi that they cultivate. A recent report notes that, rather than going to such bother, other ants simply eat the mushrooms that the forest grows for them. These ants aren't farmers, they're hunter-gatherers. In Southeast Asian rainforests, the ant Euprenolepis procera harvests a broad spectrum of wild mushrooms. They are a nomadic species that roams the forests of Malaysia, moving on when mushroom foraging goes poorly.

In the lab, they can be shown to subsist entirely on mushrooms. They make short shrift of them, typically consuming a specimen 10 cm in diameter in about three hours. In the forest, a single colony can harvest several specimens per night.

They make piles of mushroom bits, then chew them into a paste (which likely preserves the harvest) to be eaten by both workers and larvae—perhaps a dish akin to duxelles, the delicious minced mushrooms prepared by French cooks. Are these ants mushroom gourmets? Or do they eat anything they find? Just like some people, they are somewhat discriminating and eat less than half the species presented to them. The paper does not report if these include any that are poisonous to vertebrates.

The point of this study is that when observed in the lab for some three months, these ants did survive on mushrooms alone. Is this what happens out in the forest? Do these ants actually live on mushrooms and nothing else? This seems unlikely because mushrooms do not arise very reliably (one wished they would!), contain toxins, and are relatively poor in nutrients. But we mushroom lovers can sympathize.

Comments

[Isaac Arnett]

I was just watching a pile of mush that used to be a bolete. It was bubbling and upon closer look see I found the motion was caused by a maggot. I would like to know what kind of larvae is in mushrooms.

Elio replies: Mushrooms are infected by a number of kinds of flies and other insects. Larvae of sciarid gnats are particularly adept at eating mushrooms and causing considerable damage to cultivated as well as non-cultivated mushrooms. . See http://en.wikipedia.org/wiki/Sciaridae

[Fungi Publisher]

Larry, you are not alone! There are others of us mycophiles out there, enjoying Elio's wonderful blog, but not always commenting. Much of the time, I'm consumed writing for my own magazine (Fungi; fungimag.com) or at the blog there.

And Greg, the small jumping bugs are Collembola...long thought to be the most primative insects but maybe they're not actually insects afterall (but do have 6-legged, segmented bodies). What we DO know is that they're probably the most important animals in the the forest as far as cycling N and C goes. And they sure can jump. Also known as "springtails" they use their gigantic hinged spring, furcula, to propel themselves many many times their body length. Amazing!
-Britt

[Elio Schaechter]

Greg,

Dipping the mushrooms in water would certainly work. I would do it for a very short time only, lest you boil out the flavor of the mushrooms. Freezing would most likely also kill insects and their larvae. In herbaria, specimens are frozen three times to make sure. Enjoy your mushrooms!

Elio

[Greg Logan]

How does one get rid of the little jumping bugs that inhabit the mushrooms - these are not the larvae of the flies but appear to be some sort of mite - and LOVE to jump. I was thinking about a quick dip into boiling water after I brought home a harvest?

Thanks,

[Mark O. Martin]

I couldn't agree more with Larry Ayres regarding collecting these essays into a book. I'm getting set to teach microbiology in two days, and STC is a resource of great value!

[Larry Ayers]

A very nice post, Elio! But why do I seem to be the lone commenter here? There are lots of mycophiles out there, but they don't seem to have stumbled across your site. I first was exposed to the site by a local friend, a high-school science teacher. For one reason or another she doesn't comment on any blog but mine.

Hmmm.. I suspect that the ants you write about are general omnivores; they eat fungi when they are available but otherwise subsist on carrion, plants, etc. Just my supposition!

Keep up the good work! Your essays should be compiled into a dead-tree book.