Soldier Fly Stratiomys potamida Meigen 1822 and Hoverflies at Roundhill Wood

By Harry Green

On 30th June 1999 I was invited to visit Roundhill (SO985584) Wood by the owner Bob Steele, together with Joe Hardman and colleagues from Warwickshire. It was a warm day after rain and the open woodland rides were alive with insects.


Malanostoma scalare
Syrphus ribesii
Eristalis arbustorum
Erystal;is intricarius - a furry bee mimic
Cheilosia illustrata
Fernandea cuprea
Volucella pelucens
Volucella bombylans - a bumble bee mimic which is not often seen nowadays.

Soldier fly

However, the most exciting observation was of a large black and yellow insect on hogweed near a pond on the border of the wood. This was later identified as Stratiomys potamida Meigen 1822. The species is figured in Colyer & Hammond (1968).

Ball (1994) in the Recorder data base states: "A large and attractive soldier fly which inhabits marshy areas and is the only larger brachycerous fly that has become generally more frequent in recent years, especially in the north. The carnivorous larva is amphibious and feeds in shallow water in shaded seepages, stream margins, and to a lesser extent in heavily vegetated ponds and ditches. It is possibly easier to find than the adult, which is very sluggish and reluctant to fly during the emergence period from late May to early September. The adult is very large and attractive, yellow and black and resembling a fat wasp, with yellow bands on the abdomen which are often unbroken, although these are less conspicuous in the female" This species was nationally designated as a RBD 3 species but is now regarded as Notable B. There are very few records from Worcestershire.

Interestingly the Recorder script for Stratiomys singularior (reported opposite from Upton Warren by Kevin McGee) runs as follows: "Spectacular large yellowish soldier fly of brackish marshes and fens. Larvae are detritus feeding in shallow, sometimes temporary pools and are resistant to desiccation. Widespread but very local in Britain". Its national designation has similarly been changed from RDB3 to Notable B. As far as we know there have been no previous records from Worcestershire.

It is well worth keeping a look out for these spectacular flies in wetland areas.


BALL Stuart G 1994 Recorder 3.3 JNCC
COLYER CN & HAMMOND CO 1968 Flies of the British Isles.

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