[reference: Dipterist's Digest (Second Series), 1999 vol. 6:1]
Hartslock nature reserve is in south Oxfordshire, near Goring-on-Thames (v.c. 23, SU616796). The reserve is owned and managed by BBONT, the Wildlife Trust for Berkshire, Buckinghamshire and Oxfordshire, and is part of a larger Site of Special Scientific Interest. The habitat is mainly unimproved chalk grassland but this is surrounded by a combination of ancient hedges and mixed Yew (Taxus baccata) woodland. It has a south-west facing aspect overlooking the Thames, and although only 4.4 ha in area the reserve has produced records of a large number of nationally scarce invertebrates.
On 21.ix.1998 the authors were operating two mercury vapour lights at the reserve. As so often in 1998, the night was quite poor for moths, but a variety of other invertebrates were also recorded, of which the highlight turned out to be Graphogaster brunnescens. The specimen came to an MV light being operated over a sheet, and was taken and initially determined by CMR. This fly is classified as RDB 3, Rare, in Shirt 1987 (British Red Data Books 2: Insects. NCC, Peterborough). Belshaw's 1993 RES key (Tachinid Flies - Diptera: Tachinidae. Handbooks for the Identification of British Insects Vol. 10, Part 4a(i)) suggests a disjunct distribution, with records from northern Scotland and, in southern England, Wiltshire, Gloucestershire and Kent. Belshaw gives the flight period as late June to late August, so the current record extends both the distribution and the flight period (Belshaw quoting Herting states that in Europe the flight period extends to the beginning of September). Belshaw lists four micro-moths as recorded hosts for G. brunnescens; none of these are recorded at Hartslock, but the reserve's micro-moth list is not comprehensive. In any case, since the hosts come from three different families it seems likely that G. brunnescens is able to develop in a variety of smaller Lepidoptera.
The authors are grateful to Peter Chandler for confirming their determination.
CHRIS M. RAPER, [postal address withheld]
email chris.raper@tachinidae.org.uk
and
MARTIN C. HARVEY, [postal address withheld]
email: martin@kitenet.freeserve.co.uk