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Hoverflies are, in general, easily recognisable with their often yellow and black body patterns, though a number have a remarkable resemblance to bumble bees. The unique character separating them from all other flies, is a false vein or vena spuria down the middle of the wing which enables it to flex longitudinally so that they can hover with a simple up and down wing movement. Bees and wasps can do the same because each pair of wings is coupled together with a row of tiny hooks, again allowing flexing. Hummingbirds have to perform a complicated figure-of-eight movement in order to hover. A whole page could be devoted to a potted history of their very varied life styles.
This hover is commonly called the Marmalade hoverfly. The body pattern of distinctive black and orange bands separated by a thin, pale creamy band is unique in the British species. This abundant hoverfly is the one most frequently recorded and, surprisingly, can be found in all months of the year. Vast swarms migrate to Britain each year, with numbers peaking in July and August. The larva feeds on aphids on ground flora.
The larvae, called rat-tailed-maggots, live in organically rich and polluted ditches or the run-off from farmyard silage heaps and similar places. In order to respire in a liquid devoid of oxygen, the larvae have a long extensible tail which can extend to over 25cm in order to reach the surface. It is named the Drone fly due to a resemblance to male honeybees. The biblical phrase, out of strength came forth sweetness, pictured on the side of a Tate & Lyle golden syrup tin, arose from early observervations of Drone flies emerging from a rotting lion carcase lying in a pool or stream. The fly can often be seen hovering motionless with rear legs hanging down, typical of honeybees.
While the larvae of most of the Eupeodes hoverflies feed on conifer aphids, the luniger larva is a normal ground layer feeder. It is a very variable species both in size and body pattern. While numbers are boosted by migration, there is a substantial resident population.. It is common in open habitats with flowers, in fields, road verges, gardens and waste ground.
This hoverfly can be the commonest species with a striped thorax. Though other Helophilus species could be confused with this one, pendulus can usually be separated by the black on the hind tibia only reaching one third along. The larvae live in farmyard drains and other organically polluted water and they too have rat-tailed larvae. H. pendulus is a noted wanderer and is often found well away from water in any sunny situation, not necessarily among flowers. (See also the picture at the top.)
A very common hoverfly and often abundant in grasslands though it can extend its range up onto moorlands and mountain sides. It occurs from April to October, its numbers peaking in late May to early June and again in July to August. Larval stages are rarely found in aphid colonies and it is suggested that they may be generalised predators among leaf litter.
These hoverflies are fairly recognisable with their narrow bodies and somewhat elongated wings. The species can usually be found in the vicinity of trees and bushes and, as would be expected, the larvae feed on a wide range of arboreal aphids. It would be a reasonable assumption that any small greenish larva found on headstone tops in churchyards would be this species blown down from overhead trees. It is about from April to October.
Platycheirus larvae range from generalised predators to specialists on just one or two aphid species. The male flies have a greatly enlarged first tarsal joint of the front legs which might be just visible in the photo. Identification would be almost impossible from a single photo except that in this case we have a side view of the face. Below the antennae we can see a rounded bump half way down. Below that, at the bottom of the face, a long nose projects, beyond the bump above, hence the fly can be identified. The species is widespread throughout Britain.
The markings on this large, conspicuous hoverfly are very characteristic. The oblique bars on the abdomen are often whitish in contrast to other hoverflies with similar paired markings. Scaeva can be found on flowers, in gardens and meadows throughout Britain and the larvae are predacious on ground-layer aphids. Experts believe that the species arrives as a migrant and then breeds here but it is not a resident, hence numbers fluctuate wildly. Found from May to November.
Though Syrphus is one of the commonest and most familiar of hoverfly genera it is one that has seen frequent misidentifications in the past. The larvae are predacious on aphids on ground-based flora and I have bred adult flies from larvae collected in the garden. According to the Hoverfly Recording Scheme it is hard to find an unrecorded square in south and central England for S. ribesii.
[For more pictures see Hoverflies 2007. Ed.]
Three hoverflies © Michael Thompson 2007 (Canon EOS 3500 Digital 1/400 at f6.3 ISO-400 300mm lens)
Click on the image for a larger version (350Kb)
(Thoughts on a photograph by Michael Thompson)
Picture abandoned limestone quarry floor.
Rough grasses wave beneath an August sun.
Bacon and Eggs and hawthorn scrub abound.
Spotlights of colour blend with green and dun.
Focus on Centaureas purple flowers,
spurting from globular oasis base,
on which a female hoverfly reclines,
resting in satisfied postprandial peace.
In ordered queue, hovering with intent,
two macho males line up to view her charms.
Each sprays his personal aphrodisiac,
seeking to draw the lady to his arms.
She makes no move from knapweeds cosy bower,
finding their antics nothing but a bore.
With languid yawn, she settles back to sleep,
Having no time for either paramour.
© Christine Thompson 13th January 2008
All pictures © Gill Smith 2007
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