What's the point of wasps?

Iona Cunningham-Eurich

Iona is a PhD student at UCL, studying the evolution of parasitoid wasps, as well as the evolution of parasitoid prey and how this impacts speciation

Best known for pillaging picnics and delivering painful stings, social wasps, including yellowjackets and hornets, are undoubtedly some of the least popular insects in the UK. But is this reputation well-deserved, and what exactly is the point of wasps?

There are eight species of social wasp in the UK, belonging to three genera: Vespula and Dolichovespula (yellowjackets), and Vespa (hornet). There is also a recent addition, the Yellow-legged Asian Hornet, Vespa velutina, an invasive species originally from Asia and now widespread across the continent. All have social structures that resemble that of honeybees: one reproductive queen and many hundreds, if not thousands of workers who build and maintain the colony. They have an annual cycle, starting in the spring, growing throughout the summer and fading in the autumn after the Queen dies and she produces the next generation of wasps.

Given the size of their colonies that may be easily noticed by potential predators, wasps have developed excellent defensive techniques which they require to protect themselves: the sting. A sting from a wasp delivers venom into the blood stream. They can be quite painful, but it is unlikely that they are stinging for the pleasure of it. Mostly, it is just an expression of warning: “you’re too close to me!”.

Although it may seem that their only role is to wreak havoc and sting everything in sight, wasps play important roles in the ecosystem. Firstly, they are important predators and scavengers. This is one of the reasons they have large mandibles: to catch and cut up food when needed. Although adult wasps do not eat protein themselves, they must collect it to feed the larvae in the nest. Wasp larvae are not that picky regarding what they eat: caterpillars, arachnids, flies, bees and carrion are all known to be popular wasp food. Wasps therefore likely play a role in control of invertebrate populations and in nutrient cycling through decomposition. The sheer size of nests (sometimes multiple thousands of individuals) indicates that wasp foragers must be able to find vast quantities of food to feed the larvae.

Adult wasps on the other hand seek energy in the form of carbohydrates (sugars). This, they can get from pollen (or from your summertime picnics). Because of the interaction of wasps with flowers, they act as pollinators. A recent study published in Ecological Entomology even suggested that some wasp species play just as important a role in pollination as some bees (Borchardt et al., 2024). Although their importance for this service remains understudied, there is no doubt that they are important.

Finally, wasps can be important sources of food, for humans and wildlife alike: there are many places in the world, for instance Japan, where wasps, particularly larvae, are considered delicacies. People have found ways to track foragers and harvest nests, later selling their wares for high prices. They are also important sources of protein for many birds like bee-eaters (known as ‘wasp eaters’ in French and other languages) or Honey Buzzards.

Wasps therefore do play important roles in our ecosystem, and their bad reputation may not be fully deserved. We have only started to scratch the surface of our understanding about these fascinating insects, and in my opinion, are definitely deservant of our respect.