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

TRICHONTA ICENICA
A fungus gnat LOWER RISK (Nationally Scarce)
Order DIPTERA
Family MYCETOPHILIDAE
Trichonta icenica Edwards, 1913
Identification Keyed and figured by Edwards (1925) and
Gagné (1980).
Distribution Records widely dispersed in southern England
and Wales: Devon, Hertfordshire, Berkshire, Norfolk,
Cambridgeshire, Shropshire; Cardiganshire, Denbighshire,
Anglesey.
Habitat Probably damp broad-leaved woodland; some
recent records are from more or less wooded wetland areas.
Ecology Biology unknown. Members of this genus usually
develop on fungi encrusting dead wood. Adults recorded in
January, July and September to November.
Status A widespread but poorly known species with seven
known post 1960 sites, four of them provided by the NCC
wetland surveys: Aylesbeare Common, Devon (2001);
Cothill NNR, Berkshire (1977); Strumpshaw and
Brancaster, Norfolk (1988); Pentwd Marshes, Cardiganshire
(1987); Rhyd y Creau, Denbighshire (1978); Cors Bodeilio
NNR, Anglesey (1988). It is similar to the common species
Trichonta vitta (Meigen) and may be overlooked elsewhere.
Not listed in Shirt (1987) and status revised from RDB 3
(Falk 1991)
Threats Clearance of damp woodland for intensive forestry
or agriculture. Removal of old trees or dead wood which
may support development sites.
Management and conservation Maintain woodlands in a
natural state, retaining any old trees and dead wood,
especially in damp shaded situations, ensuring continuity of
these resources in the future.
Published sources Edwards (1913).
TRICHONTA NIGRITULA
A fungus gnat LOWER RISK (Nationally Scarce)
Order DIPTERA
Family MYCETOPHILIDAE
Trichonta nigritula Edwards, 1925
Identification The male genitalia were figured by Edwards
(1925) but Gagné (1981) considered the figures compatible
with synonymy with the common species Trichonta vitta
(Meigen). Chandler (1992c) re-established this as a good
species and figured the genitalia of both species for
comparison.
Distribution Scattered records mainly obtained from the
NCC wetland surveys: Wychwood NNR, Oxfordshire
(1989); Walberswick, Suffolk (1988, 1989); Catfield Fen
NNR (1988), Brancaster (1988) and Sutton Broad (1989,
1990), Norfolk; Shefford, Bedfordshire (1917); Oxwich
NNR, Glamorgan (1989); Black Wood of Rannoch,
Perthshire (1992).
Habitat Fens, carr and damp woodland. The Scottish site
was damp mixed woodland near the shore of Loch
Rannoch, below a drier pine forested slope.
Ecology Biology unknown. Members of this genus usually
develop on fungi encrusting dead wood. Adults recorded
from June to October.
Status Only recently confirmed to be a distinct species and
most recent records have been obtained by Malaise or water
trapping. It is evidently widespread with seven known post
1980 sites. It was found in numbers at the sites in East
Anglia and is probably under-recorded, its small size and
elusive behaviour probably contributing to this. Not listed
by Shirt (1987) or Falk (1991).
Threats Clearance of damp woodlands for intensive
forestry or agriculture. Removal of dead wood or of litter
layer from fens which may support fungus hosts in those
habitats.
Management and conservation Maintain existing mosaic
of habitats, retaining any dead wood especially in moist or
shaded situations. Avoid non-rotational cutting on fens or
disturbance to litter layer and vegetation and soil structure.
Published sources Chandler (1992c); Edwards (1925).
TRICHONTA PULCHRA
A fungus gnat LOWER RISK (Nationally Scarce)
Order DIPTERA
Family MYCETOPHILIDAE
Trichonta pulchra Gagné, 1981
Identification Keyed and male genitalia figured by Gagné
(1981).
Distribution A few sites in southern England: Greywell
Fen, Hampshire (1997, I. Perry); Cothill NNR, Berkshire
and Taynton Fen, Spartum Fen and Wychwood NNR,
Oxfordshire (1988 to 1990, K. Porter); Reedham, Norfolk
(1989, A. Foster and D. Procter); Oakland Wood,
Cambridgeshire (1998, C. Plant); Monks Wood NNR,
Huntingdonshire (1971, M.W. Service); Buckingham Thick
Copse, Northamptonshire (1992, A. Warne).
Habitat Damp broad-leaved woodland.
Ecology Biology unknown. Members of this genus usually
develop on fungi encrusting dead wood. Adults recorded
from May to October.
Status A poorly known species, with all British records post
1970 and only otherwise recorded from the Czech Republic
and Ontario, Canada. It was frequent in the suction trap
material from Monks Wood NNR, but most more recent
records (all except Greywell Fen) are from surveys using
Malaise traps or water traps. This suggests that the species
is elusive and may thus have been overlooked elsewhere.
Not listed in Shirt (1987) and status revised from RDB 1
(Falk 1991). This is the Trichonta species near nigritula of
Cole & Chandler (1979).
Threats Clearance of damp woodland for intensive forestry
or agriculture. Removal of old trees or dead wood which
might support development sites.
Management and conservation Maintain woodlands in a
natural state, retaining any old or diseased trees and dead
wood, especially in damp shaded situations, ensuring the
continuity of these resources in the future.
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