Although these brightly-coloured insects look like bees or wasps, they are in fact true flies and do not sting.
Hoverflies are excellent examples of Batesian mimicry. They generally mimic bees and wasps – insects that sting and also taste unpleasant, so are avoided by predators. Drone-flies mimic honey bees, Volucella bombylans has several different forms mimicking bumblebees, while others species are very convincing wasp mimics.
There are about 250 different hoverfly species in Britain. You can generally see plenty of adults on flowers throughout spring, summer and autumn. Hoverfly larvae are varied too – some even resemble small slugs. They all have different feeding habits. For example they may eat plants, feed on rotting wood and fungi, attack bulbs or parasitise other insects.