Identification

Hoverflies are amongst the most colourful and recognisable flies found in gardens. Many species are black with yellow bands or markings on the abdomen and thorax. Most have short antennae but some have relatively long antennae and resemble wasps. Some hoverflies have drab colours, being almost entirely black or brown.

A useful character for recognising hoverflies is the presence of a vena spuria or false vein that runs along most of the length of the wing in the central area. This false vein is less distinct than a real vein and is created by a crease in the wing. Hoverflies have the ability to hover in flight. Males will often hold a near stationery position in flight when they are seeking a mate.

Size

Hoverflies are 4-16mm in length. Most have relatively slender bodies but some species have broad hairy bodies and mimic small bumblebees.

Distribution

Hoverflies occur throughout Britain but some species have a restricted distribution.

Status

There are about 270 species in Britain, some of which are rare species associated with rot holes in trees and stumps.

Habitat preference

Gardens, deciduous and coniferous woods, pond, lake and ditch margins, bogs, grassland.

Where to find them in the garden

Adult hoverflies often visit flowers to feed on nectar and pollen. Most have short mouthparts and so need flowers where the nectar and pollen is easily accessible. Favourite flowers are umbelliferous plants, such as hogweed, parsnip and fennel, composite or daisy-like flowers, and ivy. They also feed on aphid excrement (honeydew) on foliage. Many hoverflies have larvae that feed on aphids so the legless larvae can be found on plants infested with greenfly, blackfly and other aphids.

Role in the garden

About half of Britain’s hoverflies have larvae that prey on aphids and other small insects, so they are useful in controlling a troublesome type of pest. Other hoverfly larvae feed in compost heaps, in tree root holes or the muddy edges of ponds and ditches. Some hoverfly larvae are plant feeders, mostly stem borers and leaf miners in wild flowers. The only garden pest hoverflies likely to be encountered are the large bulb fly (Merodon equestris) that feeds in the centre of narcissus and snowdrop bulbs, and the house leek leaf miner (Cheilosia caerulescens).