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Sarah's Species Spotlight: Wasps

Do wasps deserve their bad reputation or are they misunderstood ecosystem heroes?

We’re getting to the end of the summer which means it’s wasp season once again. They’re ready to steal your sugary snacks, get tipsy on fallen fruit, and sting anyone who gets in their way. Wasps are the punk rockers of the insect world and I’m here for it. But do wasps deserve their bad reputation or are they misunderstood ecosystem heroes?

The wasps that tend to ruin picnics are usually Common and German Wasps. Both Common and German Wasps are social; living and building nests with other wasps. They are also both carnivores for most of the year, changing to a sugary diet at the end of the summer.

Close up of wasp on a small round yellow flower

Common Wasp. © Paul Hobson

Close up of a Wasp on food scraps

German Wasp. © Jon Hawkins  – Surrey Hills Photography

However, there are around 9,000 species of wasps in the UK, and very few of them sting! Most wasp species in the UK are solitary and don’t form nests with other wasps. Some of these solitary species are also gall wasps. These are teeny-tiny wasps that lay their eggs inside plants. This causes the plant to form a ’gall', an outgrowth of tissue which becomes a nursery for the wasp larvae.

Tiny brown round lumps on the underside of a leaf

Spangle galls. © John Bridges

A greenish purple flower with pointed petals.

Broad-leaved Helleborine. © Phillip Precey

Wasps are pollinators like bees and butterflies. Some flowers have even evolved to attract them. When attacked by herbivores, like caterpillars, some plants can release ‘distress chemicals’. Some wasps have learned to follow stress chemicals in the air for a caterpillar buffet! Broad-Leaved Helleborine orchids have found a way to trick wasps. They release stress chemicals even when they aren’t being attacked to draw in the wasps. The wasps then become covered in pollen an pollinate the plant! Helleborines grow on dark forest floors where pollinators are hard to find. This may explain the advantage of wasp pollination!

There are also some species of plant that are only pollinated by wasps, such as figs! The opening to a fig flower is so small that the only pollinator of the fig, the Fig Wasp, must tear off her own wings to enter! After laying her eggs she then dies inside the fig. Her daughters will then emerge and leave to find their own fig. When leaving the wasps get covered in pollen, which they will then take to pollinate the next fig! The next time you’re enjoying a fig roll, think of the humble fig wasp that gave its life for your snack.

Wasps are also fantastic as pest control. Wasps are voracious predators of other insects and many of the insects that they hunt are crop pests. By keeping pest numbers down, wasps help farmers have higher crop yields. Wasps can also help with pests in your home! You can now buy biocontrol solutions for clothes moths only. Biocontrol solutions sound fancy, but they’re just tiny wasps you release in your house to eat the moths. Thanks wasps!

A wasps entering a nest on a wall. The asp's nest is smooth, round and papery.

Wasp nest. © Bob Coyle

When wasp nests are abandoned in the autumn you might get the chance to get a closer look. Wasp nests are paper-y structures surrounded in a round shell where the queen lays her eggs. The shell provides fantastic insulation, keeping the eggs at the perfect temperature. After hatching, the brood become workers helping to build the nest and find food. The paper for the nest comes from wood fibre collected by the queen and her worker brood. It is a time and labour-intensive process to create nests one mouthful of wood-pulp at a time. A single queen will need thousands of worker brood to achieve it. You might even be lucky enough in the spring to catch a wasp harvesting wood from your garden fence! Each tiny brood cell is a perfect hexagon made from paper. But why hexagons? The theory is that wasps use hexagons to conserve energy. The first cell needs 6 sides but following cells need less as they can share sides with previous cells - neat! Hexagons are also an optimal shape to reduce empty, useless space in the nest.

Close up of honeycomb-shaped structure

Hornet nest. © Vicky Nall

A a wasp with a red and blue body, on small white flowers.

Ruby Cuckoo Wasp. © Nick Upton

Wasps are fantastic pest control, pollinators, and architects! They are also gorgeous. The Ruby-tailed Wasp is one of the UK’s most stunning insects! They are harmless to humans and can be seen from April to September.

Close up of a yellow, black and brown hornet on wood.

European Hornet. © Vaughn Matthews

Hornets are gentle giants. Although they will sting if they need to, they prefer to avoid people. They are larger and more brown/red in colour than Common or German Wasps. They also live in much smaller colonies of around 200 – 400 individuals.

Despite sometimes being a nuisance Common and German Wasps are also very smart. It’s hard to admire them when they’re getting between me and a sweet treat though!

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