Juanita Browne: There’s a wasp in my drink, what should I do?

Why do they do that and what can I do about it?

Tue, 06 Sep, 2022 - 06:43

Juanita Browne

It’s often in late summer or early autumn that wasps cause us problems. In spring and early summer, they’re going about their business and you wouldn’t really know they’re around.

But at this the time of year, wasps can seem intent on ruining your picnic or outdoor drinks. It’s like they hear the sound of the ringpull on your drink and they’re right there beside you, like the worst party crasher.

But when you understand why they do this, you might actually feel just a little empathy towards them.

Bear with me!

When people talk about ‘wasps’ they generally mean a ‘yellow-jacket’ (Vespula spp) but there are actually many species of wasp in Ireland, including many solitary species and six social species.

Yellow-jackets are social, forming large nests, and it is their complex life cycle that attracts them to our sugary drinks in late summer or autumn. This cycle begins in early spring when the queen emerges from hibernation.

She carries stored sperm from mating the previous autumn and sets out to find a suitable nest site and starts to build her nest using chewed-up wood. She creates a cup-shaped cell in which she lays an egg and then adds more cells around it, laying an egg in each. When these eggs hatch, she catches flies, spiders and caterpillars, which she chews up before feeding them to the larvae.

Wasp nest with guard at entrance: wasps often make their nest from chewed up wood.

The first brood of her offspring to emerge as adult wasps are sterile female workers who take over the task of building and cleaning the nest, hunting for insects and feeding these to the next brood of larvae, which the queen lays in the new lower layers or ‘galleries’ of cells constructed in the nest.

Throughout the summer, the workers continue to expand the nest, adding more cells, more galleries and feeding more babies, who themselves become workers — a wasp nest is really a large group of sisters working together to help their mammy!

Surprisingly, adult wasps don’t feed directly on the insects they forage for. Instead, they feed on a sweet substance produced by the larvae in the nest. So in exchange for this sweet drink, they go out hunting, chew up their victims and feed them to their young siblings — exchanging a carnivorous meal for the dessert that the larvae produce.

This works fine when the nest is growing and thriving and there are always new young mouths to feed — in exchange for sugary goodness — but unfortunately this all changes towards the end of summer.

Towards autumn, a final gallery of larger cells is built to hold fertile males and new queens. Once these eggs are laid, the queen hangs up her boots. It is only the mated queens that will actually survive the winter, while all the workers, old queen, and males die off.

A mated queen finds a sheltered spot, hangs onto a stem or twig with her jaws and enters a torpid state until the following spring, when the whole process starts again and she begins to build a new nest.

Juanita Browne: I found a wasp nest — does it need to be destroyed immediately?

Of course, once the new queens and males have grown into adults and left the nest, this also means that the workers’ free bar has dried up too, and they’re suddenly out on their own in the big bad world. This is why they’re so drawn to your soft drinks, juice, ice cream or windfall apples.

So have some sympathy for the poor wandering wasps in the next few weeks: those wasps buzzing around your glass of cider aren’t simply evil — they’re just really really ‘hangry’ and desperately searching for one last sweet drink!