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