Hoverflies

Hoverflies belong to the insect group Diptera (true flies) and are an increasingly popular group of insects to study. Many hoverflies are distinctive in the field with their yellow and black striped bodies and hovering behaviour but there is a whole diversity to this group and many variations to get to grips with for the amateurs, or more serious, naturalist. Most species are great pollinators and of use to the gardener since their larvae eat pest aphids on garden plants and crops. In Britain about 270 species are known at present, but significant species and numbers can migrate.

The life cycle of a hoverfly is known as a complete metamorphosis with egg, larval, pupal and adult stages. Complete metamorphosis from egg to adult can take 16 to 28 days.

The main identification features to look out for are:-

All hoverflies have 2 wings hence their place in the 'Diptera' group. Other insects have 4 pairs of wings but in the Diptera the hindwings have become reduced to become tiny club-shaped structures called halteres. These halteres help control and balance the hoverfly whilst in flight.
 
The thorax of hoverflies is finely hairy.
 
The wing venation contains a false vein known as the venia spuria.
 
The wings of hoverflies have two outer cross-veins both fairly near the wing margin.
 
Hoverflies are usually robust insects, with average length legs and large eyes.

Individually these characteristics are not a 100% rule of thumb but when combined can give indication as to a preliminary identification.

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