Hover flies, Syrphidae

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Uniramia

--Centipedes

--Hexapoda 1 (insects)

--Hexapoda 2 (insects)

--Hexapoda 3 (insects)

--Identification to order level

--Insect orders

----Lepidoptera (butterflies, moths)

----Ephemeroptera (mayflies)

----Hemiptera (bugs, cicadas)

----Hymenoptera (bees, ants, wasps & saw flies)

------Bumblebees

----Coleoptera (beetles)

----Dictyoptera (mantids, cockroaches)

----Diptera (true flies)

----Neuroptera (lacewings, ant lions)

----Orthoptera (crickets, locusts)

----Thysanura (bristletails, silver fish)

----Strepsiptera (stylops)

----Thysanoptera (thrips)

----Odonata (dragonflies, damselflies)

----Trichoptera (caddis flies)

----Siphonaptera (fleas)

----Isoptera (termites)

----Phasmida (stick & leaf insects)

----Dermaptera (earwigs)

----Anoplura/siphunculata (sucking lice)

----Mallophaga (biting lice, bird lice)

----Psocoptera (book, bark, dust lice)

----Mecoptera (scorpion flies)

----Collembola (springtail)

----Embioptera (web spinners)

----Plecoptera (stone flies)

----Diplura (bristletails)

----Protura

----Zoraptera

Right, and below are hover flies (family Syrphidae).

There are 6 000 species world wide, and over 236 species in the U. K. Note the the aristate antennae and huge eyes typical of the more "advanced" flies.

Mimicry

Many mimic the colouration and/or hairiness of social bees and wasps. This enables them to avoid attack by predators who believe they might be able to sting. This form of mimicry is termed Batesian mimicry.

Food and behaviour

Many Hover fly larvae are slug-like and eat aphids (see below left), others are scavengers. Adult hover flies feed on pollen and nectar.

Flight speed has been recorded as 3.5 metres per second with a wing beat of 120 per second. Compare this with other insects. Hoverflies are valuable pollinators.

	Left is mate seeking behaviour. The male hoverfly generally has two strategies in seeking a mate. 1) He patrols around oviposition sites. The female will have already mated if she is seeking a site to lay eggs. But if the male can persuade her to mate again his sperm will have precedence. 2) He patrols over flowers. This is shown on the left. He will investigate anything that
remotely resembles a female hoverfly bouncing down to get close or even touch the insect. Mating is rarely seen.

Hover fly larvae

On the left and below left are aphid-eating hoverfly larvae. The one on the left has stuck the skins of sucked-dry aphids to its body.

Larvae like these can eat 50 aphids a day. When the larvae pupate the pupae are brown and stuck to the plant.

hoverfly larva

Eristalis larva, rat tailed maggot

On the left is Syritta sp., a hover fly larva that is found in rotting debris.

On the right is the rat-tailed maggot, Eristalis tenax the adult is also known as the drone fly, as it resembles a honeybee, and is found around the world. The adults - both males and females - eat nectar and pollen. Adult males often hover over open areas 2 - 4 m above the ground.The eggs are white, and laid on or near manure or stagnant water. The maggot's tail can be up to 4 times its body length, and the total length can reach 5.5 cm. The tail is a siphon or snorkel of three segments to allow it to breathe underwater, and can be contracted and extended like a telescope. Because it gets its air from the surface it can live in very dirty and polluted water. It looks a little like a dirty white caterpillar as it does have what appear to be prolegs. The larva moves to drier areas before pupating.

Syrphus ribesii, Episyrphus baleatus, adult hoverflies, adult marmalade fly

Above are 1 Syrphus ribesii and 2 Episyrphus baleatus, commonly known as the marmalade fly.

hoverfly

The African water lily on its first day of blooming has hundreds of showy stamens and a nice bright flower. This attracts hover flies. On day 1 in the centre of the flower is a pool of poisonous liquid that looks like nectar. When the hover fly lands on the stamen it falls into this liquid as the stamen are very smooth and overhangs the pool. The hover fly cannot climb out as there is nothing to get a grip on. So the hover fly dies in the poisonous liquid. At night the flower closes and the liquid washes pollen from day two water lilies off the body of the dead hover fly. This pollen fertilises eggs at the bottom of the liquid. On day two it is quite safe for hover flies to visit the lily as the stamens no longer hang over a poisonous pool as the pool has gone. The hover flies will gather pollen on their bodies, but will pay with their lives if they then try to do the same to a day one flower.