I know many people don’t like wasps. People are afraid of them because they buzz irritatingly and because we have learnt they sting — rather painfully. And yes they can be annoying little buzzers. Generally if you ignore them, they’ll ignore you; but if you annoy them they’ll order reinforcements (and yes they do — using pheromones!).

But I happen to think wasps are wonderful creatures, unless you are one of the unfortunate very few who are allergic to them (when they are actually rather dangerous).

In fact all the social insects (bees, wasps, ants, termites) are amazing for the way their colonies are run and organised. But I am especially fond of wasps, because without wasps we would not have life as we know it.

That sounds like an overstatement. And until the other day I might have agreed.

Vespula germanica, worker

First of all, what I already knew, is that wasps are incredibly useful predators. Without them we would be knee deep in creepy-crawlies. Our common European wasp species, Vespula vulgaris and V. germanica, predate caterpillars, and indeed other insect forms, which they feed to their grubs. Most of the other social wasps do this; and many of the solitary wasps parasitise caterpillars. In fact almost every pest insect species has at least one wasp species that preys upon it or parasitises it, making wasps critically important in natural control of pest numbers.

If you’re an insect, wasps are formidable predators with paralysing stings and razor sharp jaws. I’ve seen a common wasp catch a large bumblebee, sting/paralyse it, snip off it’s head, wings and legs and fly off with the body (which it could only just carry) — all in about 60 seconds.

Wasps will also take carrion to feed to their larvae. If you have wasps around, try leaving out small piece of red meat (raw or cooked) and if you’re lucky you can watch the wasps chopping off small chunks and taking them away. (By the way the adult wasps feed on nectar and sweet fruit which is why they become more of a nuisance in the Autumn when they look for more quick calories to keep them going.)

Wasps are also incredibly good at destroying dead wood. They use tiny slivers of wood, often chewed into paper, with which to build their nests. We have a handful of old pine logs in our garden and in a just 3 years or so the wasps have largely destroyed many of them. On a warm summer day you can watch a continual traffic of worker wasps cutting off slivers of wood and carrying them off.

All that I already knew. So now for what I didn’t know. Indeed what until recently no-one knew!

As if all the above wasn’t enough it turns out that yeasts, and especially Saccharomyces cerevisiae — that’s the common yeast we use for brewing beer, fermenting wine and proving bread — likely overwinter in the guts of hibernating queen wasps, ready to spread on the surface of fruit (especially grapes) the following summer. Yes, until very recently no one knew this, despite S. cerevisiae being scientifically very important as a “lab animal” as well as commercially (and socially!) valuable.

In a recently published piece of research (you can find fuller reports here and here) scientists worked out that many species and strains of yeasts were overwintering inside queen wasps, being transmitted in the Spring to their new larvae, which then as adults reinfected fruits. Wash; rinse; repeat.

Other mechanisms for yeast overwintering are proposed, so this may not be the only way. But it looks as if it may well be a very important way. And it is a route which was totally unknown until recently. (In fact the natural history of yeasts is generally poorly understood, despite their importance.) As always more research, and more questions, beckon.

This is why I love science. We are still making amazing discoveries like this. The more we look, the curiouser and curiouser the natural world is.

Moral: If you have wasps around, LEAVE THEM ALONE; they’re amazing little creatures which provide us some good service.