Parasitoides: Wasps not to love?

Viv Hughes

I never expected insects to be such a focal point of my experience at Studland Bay when I first arrived. I knew next to nothing about insects at the start of the summer, but the invertebrate life at Studland is so dynamic and vibrant, it's impossible not to get sucked in immediately. There is whole host of fabulous insects, but, to my surprise, the creatures that left the biggest impression was the parasitoid solitary wasp species here.

Like many people, I was not a fan of wasps - there's just something about them that seems far more malicious than their bee and hoverfly cousins, and the things I learned over the course of the few weeks would do nothing to help their reputation. It would, however, give me a newfound respect for these weird invertebrates - a horrified, slightly fearful respect, but respect nonetheless. Let me give you a brief introduction to a couple of my favourites.

A black wasp with orange stinger feeds on a green caterpillar
Thread-waisted wasp

Thread-waisted wasps

The first wasp I came across was the elegant and eerie thread­-waisted wasp. The scientific name for this subfamily is Ammophila, which literally means "sand-lover" in Greek. Makes sense, as they burrow in sand, and can be spotted quite easily along the paths around Studland making holes in the banks. These holes are not their homes, but rather where they will lay their eggs. And what a process that is!

These wasps find unfortunate caterpillars and drag them into the holes they have made, paralyze them with a sting and then lay a singular egg on the caterpillar. When the new wasp larva hatches, it devours the host caterpillar, but starts with the least important organs first to keep it in a grim alive-but-incapacitated purgatory for roughly 5 whole days. Not a good way to go. How a newly hatched wasps know how to effectively eat a caterpillar is incredible though, if not a little unsettling.

A green and red wasp on the head of a wheat grass
Cuckoo wasp

Cuckoo wasps

The other wasp that drew my attention in Studland was this cuckoo wasp (Hedychrum nobilelneimelai). Much like their avian namesake, the females will stealthily lay their eggs alongside the eggs of other wasp species, and once they hatch, the wasp larvae will consume any larva or eggs of the host wasp species. A little less gruesome than that of the thread-tailed wasps, but ruthless nonetheless.

The other strikingly obvious point of interest is the beautiful colours. The glitz! The glamour! I wasn't really aware wasps tended to stray much from their trendy black and yellowy-orange colours, so this was a surprise for me. Unfortunately, the reason behind their dazzling colouration remains a mystery, but this outer shell (cuticle) is particularly strong and sturdy in comparison to other wasps, which makes sense when you think one of the biggest threats to these little guys is the stings of the wasps they are trying to infiltrate the nests of.

These two wasps only scratch the surface of how extraordinary the wasp world can be, but demonstrate the complex, resourceful and fascinating lives these creatures live (even if they are a little grisly sometimes). Wasps currently face a bit of a public image issue, but these little guys actually play vital roles in our ecosystems and without them, we would be in a lot of trouble.

As well as being pollinators, they are are crucial in managing other insect population sizes. Did you know wasps are estimated to consume 14 million kilograms of insect life over one summer in the UK? Without them, we would be overrun with other bugs, throwing the whole ecosystem off balance. Wasps may not be the easiest to love, whether they're joining your family picnics uninvited, or committing atrocities in the caterpillar communities, but keep in mind that they are just as essential as the bees and butterflies, and if you look a little deeper, there is a lot more to them than you might expect.