On this page, Criorhina berberina - Volucella bombylans, Volucella pellucens, Merodon equestris, Cheilosia illustrata, related pages
There are four species in the Criorhina genus in Britain. All are bee mimics. The larvae live underground in wet, decaying timber. Females seeking egg laying sites fly around the base of dead tree stumps.
Above and below is Criorhina berberina, a hoverfly that is often mistaken for one of the ginger bumblebees such as Bombus pascuorum. However if you manage to get a look at its huge eyes and orange antennae there is no mistaking it. Wing length is 8 - 12 mm. Mainly seen in woodlands and hedgerows, it is widespread throughout mainland U. K. Adults favour hogweed and similar flowers, the one above and below is on scabious.
Below is Syritta sp., a hover fly larva that is found in rotting debris, compost, farmyard manure and silage.
There are five British species in the Volucella genus.
Above and below is Volucella bombylans, a bumblebee-mimicing hoverfly. There are different colourations of this fly to mimic the different bumblebees. The three main colour morphs imitate Bombus terrestris, B. lapidarius and B. pratorum. The different coloured hoverflies can interbreed. The larvae scavenge in the nest of bumblebees, or in the wasp, Vespula germanica. They feed on dead workers and larvae, dropped food and other scavenging invertebrates. The adults are found in and around open woodlands from May to August feeding on thistles, scabious and brambles. Males are territorial defending their own sunny patch from other males. Wing length is 8 - 14mm. They have a plumose arista (third segment of the antennae), as can be clearly seen in the photograph below.
Volucella pellucens, above, is usually found in woodland, but will occasionally be found in gardens near woods. Males are usually the most easily spotted as they tend to hover at or a metre or two above head height, and can be highly territorial. They are fairly common throughout Europe and east right across the world as far as Japan. They are bumblebee mimics, and have the common name of Great pied hoverfly. The adult body length is 13 - 17mm, and wing length 10 -15mm.
Adults eat nectar and pollen, and are particularly fond of brambles. They fly from May to October. After mating the female enters the nest of Vespula vulgaris (the common wasp) or Vespula germanica (the german wasp). Wasps guard the nest entrance to protect the grubs and queen, but somehow, the guards do not stop the female hoverfly. Once inside the female lays her eggs. On hatching the eggs drop the the base of the nest and eat whatever is there, debris, other insects and even dead wasps. They will climb up and feast on the wasp grubs if they cannot find enough to eat. Once they are fully grown the grubs make their way out of the wasp nest and drop to the ground to pupate in the soil and emerge as adults the following May or June. If the wasp nest is indoors the grubs will wander about to try to find a suitable place to pupate. Adults have a short life of just 2 - 5 weeks.
Merodon equestris, Narcissus bulb fly, Greater bulb fly, Large narcissus fly is above and below. This hoverfly comes in a few different colour forms mimicking bumblebees. One important clue in the identification of this hoverfly is the loop that one of the wing veins makes. This can be clearly seen in the photograph above. There is also a triangular projection on the femor of the hindmost leg. Wing length is 8.5 - 10.25 mm, wingspan 20 mm and adult body length is 10 - 15 mm.
It is found from Finland in the north to the Mediterranean in the south, and from Ireland in the west right across to Japan. It has also been recorded in New Zealand and the west coast of Canada and the U. S. A. As its many common names suggest the larvae feed on flower bulbs, and can destroy a bulb, so are considered a pest. The female lays her eggs on the base of a leaf, and on hatching the larva tunnels into the bulb. The larvae overwinter inside the bulb, and can take 300 days to grow. The adult feeds on nectar and pollen. In the U. K. the adult flies from April till September, and each adult lives for just 5 - 24 days.
I found this male on a cold May morning, and he seemed quite happy to gain warmth from my hand.
Cheilosia illustrata is above. It is a little like a bumblebee, but not nearly as good a mimic as some of the others on this page. It is fairly widespread around the U. K. Often found on or near hogweed and similar flowers. Wing length is 8.5 - 10.25 mm. Body length 9 - 11 mm. Adults fly from April to September.
The larvae live in the stems and roots of hogweed and similar plants.
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