Dorset Wildlife Trust’s conservation officer Hamish Murray wants us all to reconsider our opinion of the UK’s ‘stinging pests’
All images © Hamish Murray
If there was a popularity ranking for insects, wasps would probably occupy the bottom spot. However, the vast majority of the more than 7,000 species of wasp found in Britain are completely harmless to humans and, in most cases, highly beneficial as effective pollinators and predators of pests. Even the handful of species considered as ‘stinging pests’ are an important part of the overall ecosystem.
Firstly, not everything that looks like a wasp is, in fact, a wasp. Many other insects – including moths, sawflies and hoverflies – have evolved colours and markings that resemble wasps. This is known as Batesian mimicry, a strategy in which a harmless species gains protection by resembling an unpalatable or harmful species. Yellow-legged clearwing moth and figwort sawfly are two examples of wasp imitators.
Wasps are a fascinating group of insects that exhibit an enormous variety of colour, shape and lifestyle. Here are just a few of the many species to be seen in Dorset:
Heath potter wasp
This scarce solitary wasp can be found on heathland sites where there is a supply of water and suitable soil from which the female can construct a nest (pot), in which she lays a single egg. The pot will be provisioned with several moth caterpillars to feed the developing wasp larva before it is sealed. Each female will construct around 25 pots, usually attached to gorse or heather plants.
The distinctive shape of the wasp’s abdomen makes identification relatively easy.
Purbeck mason wasp
Found only on a few heathland sites in Purbeck, this attractive wasp is one of the UK’s rarest insects. The Purbeck mason wasp frequents areas of open ground which have a nearby source of clay and water for nest building.
A plentiful supply of bell heather is also required – it provides a source of nectar for the adult wasps and is also the chosen food of the heath button moth caterpillar which, in turn, is the sole food of the mason wasp larva.
Ichneumon wasp
The ichneumon wasps are a huge family, comprising more than 2,500 parasitoid insects in the UK alone. They vary enormously in size, shape and colour but are generally narrow-waisted insects with extended antennae and long female ovipositors. Identification of species is often very difficult in the field and, despite many species being large and colourful, ichneumon wasps still tend to be the subject of specialist study.
Purseweb spider wasp
There are 44 species of spider-hunting wasps in Britain. As their name suggests, they specialise in catching and paralysing spiders to feed their young. The purseweb spider is the only known prey of the purseweb spider wasp. Both species are designated as Nationally Scarce and found mainly in southern England, including along the Dorset coast where it has a particular liking for wild carrot.
Beewolf
This large and impressive solitary wasp was once considered an extreme rarity in Britain, but since the 1980s there has been a huge expansion of its range and it is now a familiar sight among Dorset’s heathland fauna. The female beewolf captures honeybees and carries them under her body back to the nest burrow to feed the developing young.
Broad-banded digger wasp
There are 120 species of British digger wasp and many of these have the same black and yellow colouration, which can make identification extremely difficult. The broad-banded digger wasp is a rare species which preys on small bugs such as froghoppers. It has characteristic broad bands on the abdomen and extensive yellow face markings.
Hairy sand wasp
One of four species of British sand wasp, the female hairy sand wasp overwinters as an adult and emerges on warm days in March, long before the other three species make an appearance.
The wasp’s nest burrow is provisioned with a single large caterpillar to provide food for the larva. Despite being designated as Nationally Scarce, hairy sand wasps can be found over much of Dorset’s heathland and are often seen feeding on fleabane and other nectar-rich flowers.
Javelin wasp
With its ridiculously long, white-tipped ovipositor, clubbed hind legs and strange posture, this is certainly a distinctive insect. The ovipositor is, in fact, a very effect tool for laying eggs in the nests of solitary bees and wasps. Javelin wasps occur over much of Dorset, sometimes appearing in gardens.
