On this page,- Eristalis tenax, rat-tailed maggot, drone fly - Eristalis horticola - Eristalis nemorum - Syrphus ribesii - Episyrphus balteatus, marmalade fly - Chrysotoxum arcuatum - Sericomyia silentis, Helophilus pendulus, Sun fly - related pages
Sericomiya silentis larvae are the rat-tailed type - see the drawing below of Eristalis tenax. They are found in drainage ditches, peaty pools and bogs.
The adults are found along woodland edges and tracks on flowers when it is sunny. This one was found in Craigmyle woods on scabious in August. Adults fly from May - November. Adult body length is around 16 mm making it one of the largest British hoverflies.
Some species of hoverfly are aquatic, and often these are commonly known as rat-tailed maggots. Above is an Eristalis tenax adult, it is also known as the Drone fly, as it resembles a male honeybee. It is found around the world.
The eggs are white, and laid on or near manure or stagnant water.
The maggot's tail (see the drawing below) 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 can even survive in sewage and farm manure!
It looks a little like a dirty white caterpillar as it does have what appear to be prolegs. It feeds on organic particles. The larva moves to drier areas before pupating.
The adults - both males and females - eat nectar and pollen. Body length is 14 - 16 mm. Apart from the head it really does look like a honey bee.
They can be seen year round in warm, sunny weather, but are most common in August and September. They overwinter as adults in cellars, sheds, hollow trees, etc.
Adult males often hover over open areas 2 - 4 m above the ground. Below you can see a pair mating on a sunny wall.
Above is an adult Eristalis horticola in its typical habitat of white umbelliferous flowers. It is found throughout the U. K., but is more common in the north.
The larva is similar to Eristalis tenax, above, in that it has a long tail for breathing in poor quality aquatic habitats.
Above is Eristalis nemorum. It can be identified by the black or dark brown patch or stigma on the outside edge of its wings. The hair is creamy yellow. Wing length 8.25 - 10.50 mm. Larvae are of the rat-tailed type (see above).
The adult flies from April to October. It is found right round the globe from Ireland to Japan and across North America. When courting the male hovers over the female, and it has been reported that sometimes they are stacked like aeroplanes waiting to land at an airport.
These are medium to large flies with a wing length ranging from 5.75 - 12.25 mm. The thorax has longitudinal stripes in yellow or grey. They are found in marshy or wet locations. The larvae are the "rat-tailed" type, so are found in stagnant or nearly stagnant foul water and moist dung. They are sometimes called Tiger hoverflies.
Above is Helophilus pendulus, the Sun fly. It is found throughout Europe, across Russia to the Pacific. It is common in damp, marshy places, and the adult is attracted to flowers. Males can often be seen hovering over ditches, and similar places waiting for females who will lay their eggs there after mating. Wing length is 7.25 - 11.25 mm., body length up to 13 mm. Adults can make a buzzing noise.
The larvae are the "rat tailed" type - see above. Larvae can be found from May to November, and adults from April to October. Sometimes called the Footballer hoverfly because of its stripy thorax.
Chrysotoxum arcuatum (above) is frequently found in Scotland, but less common elsewhere. The adult flies from May to September, and is most common near woodlands.
Below is Syrphus ribesii. Adult body length is 9 - 13 mm. Adults are commonly seen flying from April to October, and is abundant in the U. K. It is found in most habitats, and the adults visit flowers of many types.
It overwinters as a larva in leaf litter. The larva is soft grey/brown white and looks a bit like a flattened slug (see the drawing below) and eats aphids.
Episyrphus balteatus, above and below, commonly known as the marmalade fly, and is one of the most common hoverflies in the U. K. Adult body length 7 - 11 mm, and wing length 6 - 10 mm. Flies from May to October, but most commonly seen in July and August. It overwinters in the U. K. as an adult, but may not survive very cold winters.
Above is a close up of the head showing the huge eyes, the mouthparts and sausage-shaped antennae.
Adult males are territorial, and within the territory will display to females and chase off any other males.
From egg to adult takes around a month. There are usually 2 generations per year.
Adults feed on nectar, and their favourite flowers are hogweed, cow parsley, ragwort and thistles.
The female lays her eggs on plants where there are aphids.
The larva eats aphids from a wide variety of plants, but seems to have a preference for aphids located lower down on the plant. A single larva will eat around 200 aphids before it pupates. Usually it pupates near the aphid colony.
Above and below is the pupa of Episyrphus balteatus, Marmalade fly. I found it stuck to the inside of a bag of my own compost. It pinged off the side when I opened up the bag. I took it inside and left it on my desk until the fly above hatched out. The adult had a damaged wing, see the top photograph, which I supposed happened when the pupa came off the bag. The fly couldn't use its wings properly, so I put it into my greenhouse close to flowers.