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  • Writer's pictureHarry

Wasps - what do they do?

Updated: Mar 31, 2023

It's not a good sign if an insect gives its name to a word for anger and irritation. Waspish they may be but surely wasps don't exist just to annoy us?

With their loud buzz and stripey yellow/black bodies, our instincts tell us to avoid them and their stinging ways. But how come there seem to be so many at this time of year and what role do they really have in the world?

For most people, wasps are just a bad thing - something to be swatted away from picnic sandwiches and fished out of sugary drinks.

The wasps we usually notice look like the Saxon wasps in the picture. Although they most often capture our attention, they represent only a few of the 7,000 or so species of wasp in the UK. They are social insects; forming large colonies with many related members. The way they Iive and reproduce explains why they can be so aggravating to humans - and so important to the environment.

The wasp's year begins in spring. Queens produced from last year's colonies will have hibernated over winter and as the weather warms up, they start to emerge. A queen must find a suitable site so she can build a nest from scratch. Depending on the species, this might be in a tree, in the ground or in a man-made structure. Once she has chosen a spot, she will use chewed wood (perhaps stripped from a fence panel) to make the first few cells of her nest.

She'll start laying eggs in these cells. Once they have hatched, she'll forage for food to feed the growing larvae - this is where it gets interesting. The wasp's big jaws are made to catch other insects but they don't do this for themselves. Wasps catch insects to feed to their developing larvae. Having caught an insect, they cut it into pieces with their strong jaws before taking the pieces back to the colony. So, wasps play a really important role in ecosystems because of the quantity of insects they catch - estimated at around 14 million kilos of insects each year. Without wasps, we'd be overrun with caterpillars and greenfly!

Given their big jaws, it's surprising that adult wasps can't eat the food they hunt. They can only feed on nectar and so, as well as pest control, they also act as pollinators. Although they aren't as efficient at this as bees, wasps have their part to play in pollination.

This need for sweet things brings us to their interaction with humans.

The queen's first larvae mature into adults and the colony begins to grow. The queen lays more eggs; the worker adults (all female) expand the nest and go out hunting to feed the new larvae. As a reward for this food, the larvae produce little drops of sweet liquid for the returning adults. Unfortunately, these sweet times don't last. Toward the end of summer, the nest reaches its maximum size and primes itself to reproduce. The queen will lay drone eggs (males) and about 1500 queen eggs. After she has laid these special eggs she won't lay any more. The worker wasps rear the queens and drones, who fly out to mate. Having mated, the drones die. The queens look for somewhere to hibernate for the forthcoming winter - ready to emerge next spring to build their own nests.

No more larvae develop and so the remaining adult wasps have lost their main source of sweet food. This is when wasps can really cross paths with humans. The wasps search for any food that contains sugar - rotting fruit, nectar from the last summer flowers and of course, sugary drinks. Its a particularly stressful time for beekeepers because a late summer beehive full of honey is a great source of sugar. Hungry wasps can easily overrun a weak hive and every year beehives are lost to wasps.

The old queen's nest is now on a final countdown. As the weather gets colder, food sources disappear. Rather sadly, having sent their new queens off into the world, the old queen and all her worker daughters eventually die of starvation.

So, although wasps can definitely be aggravating, they are important predators and pollinators - helping to keep harmony in the natural world. It's not always possible to ignore them (especially if you are a beekeeper or if they have made a nest in your shed) but perhaps we can learn to tolerate them. After all, they'll be gone soon.

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