Introduction to flies

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Flies, known technically as Diptera, are the dominant insects in many habitats. The group includes just a few species that are highly damaging to man and to wild and domestic animals by carrying diseases – mosquitos carrying malaria being the prime example – but also includes some that are beneficial, such as hoverflies. There are many different species, often looking like bees or wasps for self-protection. Bees and wasps have two pairs of wings and a distinct 'waist' where their thorax meets their abdomen, whereas flies only have one pair of wings, no waist, and no sting.~bumblebee hoverflyflesh fly

Adult hoverflies feed on nectar like bees, so are valuable as pollinators. The young (larvae) of many species feed on aphids, so it is a good idea to try to attract them into your garden. Some, however, lay their eggs in bee or wasp nests, where they scavenge within the nest, and one, the narcissus fly is regarded as a garden pest, because its young eat bulbs.~hoverfly larva

Hoverflies vary considerably in size. The largest, like the bumblebee hoverfly, are as big as bumblebees and look very similar, whereas the smallest, like the marmalade hoverfly, are only a few mm long.

The dronefly, which mimics the honey bee, is one of the commonest hoverflies, appearing from late spring and throughout the summer wherever there are flowers. Another common species, the banded hoverfly, is very wasp-like.

Of the myriad other species of fly found in Britain, probably the bluebottle and the crane fly are the most familiar, the former because it is often found in houses and the latter – known as daddy long legs – because it is often seen flying round drunkenly in gardens.

Many flies are parasites, laying their eggs in or near their chosen hosts, but some, like the empid fly and the hornet robber fly are hunters, preying on other insects.

Another particularly interesting fly is the bee fly, so called because it is furry like a bumblebee. It is most noticeable in spring feeding on flowers such as primroses and violets. All the above are 'true' flies, belonging to the order Diptera, but a number of other insects are also referred to or seen as flies, such as the scorpionfly.