Hoverflies

At the beginning of 2012, thirty-two species of hoverfly had been recognised as being present in the area, although some of these (marked with a "?" in the list below) were not positively identified. Hoverflies make good and attractive subjects for photography, and the lack of positive identification reflects this - it is my policy usually to photograph the creatures rather than to capture them as would be required for a more positive identification. Many of those listed have been observed in my garden at the south edge of Wanstead Flats, and the preponderance of this location in the "Locality" column should not be taken as suggesting that the species is not present elsewhere.

The species are listed in natural order, and I shall work through the apparent status of each in that way.

The first is the small Baccha elongata , a member of the Tribe Bacchini. This is probably much more common than my records suggest, and particularly so in the garden. It is a distinctive species with a long narrow body that ends in a bulb. The male of Melanostoma scalare also has a long body which tends to taper slightly towards the rear. There is a similarity between this species and Platycheirus clypeatus, and some uncertainty in my identification, but it appears that both species are present. The related Platycheirus ambiguus is only represented by a possible specimen in the garden on 20th April 2011.

Turning now to the Tribe Syrphini, one member of the Dasysyrphus has been found - Dasysyrphus albostriatus, just once, and a slightly tenuous identification - in Wanstead Park. Chrysotoxum bicinctum is a striking black and yellow coloured hoverfly, and perhaps because of its attractive colours is well recorded from the garden and also from Wanstead Flats. Chrysotoxum verralli has only been recorded on one occasion, in the Aldersbrook Exchange Lands when there were numbers of them feeding on hawkweeds in June 2007. The other Chrysotoxum species is C. festivum, which has only been recorded twice - in Wanstead Park in July 2010 and in the Exchange Lands in August 2011.

Hoverflies of the Genus Epistrophe are represented commonly by Epistrophe eligans, which is common in the garden, has been seen in the Bush Wood area and Wanstead Flats, and is almost certainly present commonly elsewhere. A possible Epistrophe nitidicollis was also photographed in the garden in late September 2004. Episyrphus balteatus must be one of the most easily recognised species, and also has the rare honour of having a fairly common English name - the Marmalade Hoverfly. The reason is clear, from the colour and just how common it is. Eupeodes luniger is another quite strikingly-coloured hoverfly, black with yellow comma-like markings on the abdomen; this species has been seen frequently in the garden, but also in Wanstead Park. Meliscaeva auricollis should be another easy to recognise species - another of the long-bodied types - but has only been photographed once, in the garden.Scaeva pyrastri  has only been noticed a couple of times: in the garden and on Wanstead Flats, although the specimen on the Flats was quite distinctive with particularly whitish markings. It is a relatively large species and occurs throughout much of Britain in such places as these, so should be quite common here. Significantly different in size, the smaller Sphaerophoria rueppillii has only been seen once, in the garden in May 2008. It should be noted that this is a local and uncommon species, and I introduce a reminder here that there may be a mistake in my identification. Sphaerophoria scripta on the other hand, although quite similar has a particularly long abdomen making recognition quite easy, and it is also much more common, over open grassland such as Wanstead Flats and the Plain, and is also often seen in my garden. 

Of the Genus Syrphus, Syrphus ribesii is noted to be one of the most familiar hoverflies in Britain, although as usual there are similar species. As such, I have records from my garden, although its varied habitats mean that it is probably very common throughout the Wanstead Wildlife area. Syrphus torvus can be very common also, but with more peaks and troughs to its flight-season than ribessii. It is particularly fond of woodland, so should be present, and it is said to be one of the common species at willow catkins. I have photographs of what I believe to be this species on such catkins in the City of London Cemetery and a close look indicate the hairy eyes which distinguish this species from other similar ones. Syrphus vitripennis  is another common and widespread species, and I have pictures of males only from both the garden and the City of London Cemetery.

Much more easily identified are specimens of Xanthogramma pedissequum of the Genus Xanthogramma. These really are a nice looking black and yellow species, and have been seen in the garden and in Wanstead Park on numerous occasions.

Only one specimen of the Genus Cheilosia, and that may be Cheilosia albitarsis, one of which was found in Wanstead Park on 30th May 2011. It is widespread and abundant in Britain, and may well locally be an overlooked species.

From the Genus Neoascia, Neoascia sp. is the best I could do with a very small hoverfly with a narrow waist and a bulbous rear. It may be N. podagrica, and was photographed in my garden.

To the Genus Eristalis; these tend to mimic bees to a greater or lesser extent, though the short antenna should readily distinguish them.  Eristalis intricarius  is quite a handsome very furry bumble-bee mimic which I have seen in Wanstead Park, Eristalis pertinax is another common and widespread species, and is present from early to late in the year, and is common here in the garden, the Exchange Lands, Wanstead Flats and Park and doubtless other areas too. Lastly Eristalis tenax  - known as the drone-fly - is a honey-bee mimic and has been sighted in the garden, the Exchange Lands and Wanstead Flats.  

Species of the Genus Helophilus have distinctive yellow bands running down the thorax (the area behind the head), and Helophilus pendulus seems to be common, having been seen in the Exchange Lands, Wanstead Park and particularly my garden where it loves to sit around the pond. Only one record of Helophilus hybridus, and that is from Wanstead Park on 6th June 2013.

The Genus Myathropa is represented by Myathropa florea , a wasp-mimic with a pattern of grey spots and bars on the thorax which makes it quite distinctive. It is common in all areas.

Of the Genus Pipizella, the small Pipizella viduata may be the species that  was photographed in the garden in April 2011, but I am uncertain.

The large and distinctive Volucella bombylans, as its name suggests, is a bumble-bee mimic - even to the extent that a variety has a red tail and another a white tail. It is of the Genus Volucella. It is a widespread species in Britain, but I have only recorded it hereabouts in my garden. Another Volucella is V. inanis, in this case specimens have been seen in the garden and also in Blake Hall Meadow. The outer suburbs of London are reputed to be one of the strongholds of this species, which appears to be increasing its range northwards.  V. pellucens is a large black hoverfly, but with a wide band of white across its abdomen and dark marks on its wings. This makes it quite a handsome and dramatic creature, with the addition of a distinct orange facial mask. It has occurred not infrequently in my garden, in the City of London Cemetery, in Wanstead Park and in Blake Hall Meadow. The last Volucella is V. zonaria. This really is a large and dramatic species, yellow and black with chestnut wings and a very distinct facial mask. The garden, Wanstead Park and Blake Hall Meadow are all known haunts of this species. It is another species which has a liking for the London suburbs, and since its establishment in Britain in the 1940s has and is continuing to expand its range.

The last species is a complete contrast in size - a member of the Genus Syritta and its only representative in Britain - Syritta pipiens. It has a long narrow abdomen, black and yellow, and is abundant in a variety of habitats which should make it quite common here. I have only recorded it from my garden, however.

The book that I use primarily as a guide to hoverflies is "British Hoverflies" by Stubbs and Faulk, and some of my comments here have been guided by that volume.