Fróðskaparrit - 01.01.2002, Page 146

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THE BITING MIDGE CULICOIDESIMPUNCTATUS GOETGHEBUER, 1920
(DIPTERA: CERATOPOGONIDAE) RECORDED FROM THE FAROES
Introduction
The biting midges (Culicoides Latreille)
are minute (wing length rarely >2mm),
mainly crepuscular nematocerous flies.
The females usually require a blood meal
for the successful development of eggs. In
some cases the biting activity of female
Culicoides is a nuisance to animals and
man and the species Culicoides impuncta-
tus is a particularly troublesome biter. This
paper reports on the first record of the
species from the Faroes.
Materials and methods
Insects were collected by means of a
portable, battery-operated light trap (Ento-
Tech light weight trap, I I Watt fluorescent
PL-light tube Osram Delux/color; Olsen et
al., 1984). Collecting was done in three
sites on Streymoy: 1. At the settlement
Gerðinum (at sea level), Vestmanna. The
light trap was placed on the outskirts of the
settlement, about40 m from human habita-
tions and operated for four nights (July 29
- August 1,2001). In the site the moist soil
was covered with grass and moss; horses
were grazing in the pastures. 2. Mýrarnar
(mountains about 400 m above sea level;
trap operated for four nights, July 25-28,
2001). Predominanl habitats: moist rocks
covered with moss and bogland with peat-
based mire vegetation made up of grass and
bog moss (Sphagnum spp). The latter area
provided summer pasture for sheep. 3. Fur-
ther, among insects collected in a light trap
placed at Hoyvík on the outskirts of Tórs-
havn a male and a female C. impunctatus
were found (June 24 - July 16, 1991, leg.
Peter Gjelstrup and Svend Kaaber).
Results and discussion
A total of 142 specimens (2 S S, 140 2 S) of
C. impunctatus were trapped, viz. at
Gerðinum 22 2 and at Mýrarnar 2SS,
1382 2. Thus nearly all specimens were
collected in the site Mýrarnar, which re-
flects that C. impunctatus is a bogland
species breeding in oligotropic, peaty sites
characterized by bog moss (Sphagnum
spp.)(Kettle, 1984).
C. impunctatus is widespread, occurring
in Europe and Asia (Remm, 1988); in Eu-
rope it is recorded from e.g. Britain (in-
cluding Orkney), Denmark and Norway
(Campbell and Pelham-Clinton, 1960;
Nielsen, 1964; Halldorsdottir et al., 1989).
The species is not known l'rom Iceland and
Greenland.
In some species of Culicoides the female
antennal ratio (the ratio of the sum of the
length of the apical five segments of the an-
tennal flagellum to the sum of the basal
segments) has been found to vary in rela-
tion to absolute size, generally increasing
with increasing body size (Campbell and
Pelham-Clinton, 1960). The mean antennal
ratio of Faroese C. impunctatus (n = 9,
0.981 ± 0.028) is significantly lower than
the mean ratios recorded from Britain
(Campbell and Pelham-Clinton, 1960;
North Britain: n = 13, 1.057 ± 0.0080, p <
0.001; South Britain: n = 15, 1.016 ±
0.0071, p < 0.001) and Denmark (Nielsen,
1964; n = 2 6, 1.02 ± 0.039, p < 0.01), but
seems, if anything, comparable to the ratios
recorded from e.g. France, Slovakia, and
the former Soviet Union (Kremer, 1965;
Országh, 1976; Glukhova, 1989). However,
since the Faroese specimens were all