Part 2: Nematocera and Aschiza not dealt with by Falk (1991) - JNCC

Published sources Chandler (1992c); Cole & Chandler
(1979); Gagné (1981).
DIAZOSMA HIRTIPENNE
A winter gnat LOWER RISK (Nationally Scarce)
Order DIPTERA
Family TRICHOCERIDAE
Diazosma hirtipenne (Siebke, 1863)
Identification Keyed by Edwards (1938), Freeman (1950a).
Distribution Records thinly scattered in England
(Wiltshire, Hertfordshire, Buckinghamshire, Herefordshire,
Lincolnshire, Leicestershire, Yorkshire, Durham), Wales
(Caernarvonshire) and Scotland (Roxburghshire, Elgin,
Easterness).
Habitat Mainly broad-leaved woodland.
Ecology A female was found flying in the cavity of an old
hollow Elm (Ulmus) at Grimsthorpe Park, Lincolnshire,
suggesting a potential breeding site. Basden reared a male
Diazosma from the nest of a blue tit or robin in
Buckinghamshire (1931) but the nest was situated on damp
decomposing vegetable matter 2 feet from the ground in a
small hollow Elm (Ulmus) stump. Adults are on the wing
from June to August.
Status Little information and it has probably been
overlooked to some extent. There are twelve post 1960
records: Plucking Grove Wood, Lackham Park, Wiltshire
(2002); Rotherfield Park, Hampshire (2002); Aldbury
Common, Hertfordshire (1997); The Coombe,
Buckinghamshire (1997); Grimsthorpe Park, Lincolnshire
(1972); Hatfield Moor (1991) and Duncombe Park NNR
(1996), Yorkshire (1991); Nesbitt Dene, Durham (1992);
Coed Tremadog NNR, Caernarvonshire (1976); Newtown
St Boswells, Roxburghshire (1988); Doune of Relugas,
Elgin (1965); Butterstone Loch, Easterness (1991).
Threats Woodland clearance for agriculture or intensive
forestry. Removal of old or diseased trees, which may
support breeding sites.
Management and conservation Maintain habitat diversity
in woodland, retaining any old or diseased trees or stumps,
ensuring continuity of habitat in the future.
Published sources Chandler (1977d, 2003); Edwards
(1938); Payne (1967).
TRICHOCERA MACULIPENNIS
A winter gnat LOWER RISK (Nationally Scarce)
Order DIPTERA
Family TRICHOCERIDAE
Trichocera maculipennis Meigen, 1818
Identification Keyed by Freeman (1950a) and Laurence
(1957).
Distribution There are isolated records for southern
England (Somerset, Kent) and scattered records for the
Midlands and north of England (Staffordshire, Derbyshire,
Cheshire, Lancashire, Yorkshire, Durham, Westmorland),
Wales (Breconshire, Denbighshire) and Scotland
(Midlothian).
Habitat Strongly associated with caves, although possibly
utilising other shaded damp environments including old
mines.
Ecology Larvae probably develop in decaying matter, such
as animal dung in caves or rotting vegetation and fungi
elsewhere. Adults recorded throughout the year.
Status Four known post 1960 localities: Castle Eden Dene
NNR, Durham (1975); Moor House NNR, Westmorland
(1963 to 1967); Ogof Ffynnon, Breconshire (1979); Ogof
Dydd Byraf, Denbighshire (1972). Possibly overlooked due
to its secretive nature. Status revised from RDB 3 (Shirt
1987).
Threat Quarrying as well as the degrading of cave systems
by caving activities and general tidying up for tourism.
Management and conservation Maintain caves in a natural
state, placing limits on the amount of disturbance.
Published sources Edwards (1938); Kidd & Brindle
(1959).
MYCETOBIA GEMELLA
A wood gnat
Order DIPTERA
Mycetobia gemella Mamaev, 1968
DATA DEFICIENT
Family MYCETOBIIDAE
Identification The species of Mycetobia are keyed by
Mamaev (1968). The females are keyed by Hancock et al.
(1996).
Distribution Three sites in the Scottish Highlands are
known for this species: Abernethy Forest NNR (1994,
1997), Glen Affric (1996) and Rothiemurchus (1991),
Easterness (rearings by the Malloch Society).
Habitat All sites are Caledonian pine forest.
Ecology All rearings were from Scots Pine (Pinus
sylvestris). The Rothiemurchus record was a rearing from a
rot hole (emergence of adults in late June to early July) and
the earlier Abernethy Forest NNR record was from a water
run (resembling a sap run) on a trunk and from under bark
of a dead standing pine (adults emerged late May to mid
June).
Status More than 40 individuals were reared from the above
sources. The species was identified only in 1994 and was
added to the British list by Hancock et al. (1996). Its
distribution will continue to be investigated by the Malloch
Society, and it is possible that it will be found to occur more
widely in the remaining Scottish pine forests. As with M.
pallipes Meigen, finding larvae is probably easier than
finding adults. Currently there is inadequate information to
assess the risk of extinction. Not included in Shirt (1987)
and Falk (1991). Rotheray et al. (2001) recommended RDB
3 status.
Threats Clearance of native pine forest for agriculture or
commercial forestry. Prevention of regeneration of forest by
deer grazing.
Management and conservation Maintain remaining
Caledonian pine forest with old and decayed trees.
121