David Element's Wildlife Web Page Flies 2

David Element

Wildlife Photography

and Digital Video Images

_____________________________ Flies 2 - Hoverflies 2

Scaeva pyrastri

BANDED HOVERFLY Volucella zonaria

Volucella inflata

Volucella pellucens

Criorhina ranunculi Doros profuges

Arctophila superbiens

Callicera aurata

There are almost 280 named hoverfly species on the current British list. Many of these are very similar in appearance and difficult to identify - indeed it is often easier to sex these insects than it is to identify them to species level. The eyes of most male hoverflies touch at the top of the head, so all eight examples shown above appear to be females. The adults of some of the rarest species are seldom seen even by expert entomologists and therefore their life-histories and conservation requirements are poorly understood, and by inference probably highly specialised. Although many species closely resemble bees or wasps they are entirely harmless and they cannot sting or bite.

The Banded Hoverfly is classified as Nationally Scarce. Although these insects are usually observed in ones and twos, the photographer saw an unprecedented total (for him) of at least 16 of these impressive hornet mimics during a walk in south London on 5th August 2001. The subterfuge is at its most convincing when this fly is in flight. Banded Hoverflies may be seen feeding avidly on buddleias, thistles, umbellifers and other nectar sources and in common with some other species their numbers are reinforced periodically by migration from continental Europe.

Most of the species shown above are uncommon or genuinely rare apart from Scaeva pyrastri, a significant migrant, and Volucella pellucens, the larva of which inhabits social wasps' nests and lives on detritus. Other members of the Volucella genus also exhibit this behaviour and it is likely that their larvae either offer an appeasing sweet substance to the wasps or employ some form of pheromonal chemical mask in order to avoid attack (and also presumably enjoy the protection afforded by a nest full of worker wasps!). This is speculation and any proof (or otherwise) would be welcomed if there are any experts studying this relationship.

The predominantly northern and western distribution of the bumble bee mimic Arctophila superbiens suggests that this insect thrives in cooler conditions than most British hoverflies and the species may therefore be susceptible to global warming. This fly was previously classified as Arctophila fulva, but unfortunately this scientific name had already been selected for an Arctic plant. Whether the discovery of this duplication was the motivation for the re-naming is not known!