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British Culicoides
Contents | Introduction | Individual species pages | References
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Photograph of wing at right: click to enlarge.
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The wings are vaguely marked with the second radial cell pale. It is easily distinguished by the form of the male genitalia, in particular the deeply cleft (but not completely divided) ninth sternite; the antennal ratio is 1.04-1.23, the sensilla distribution 3,11-15. The females of obsoletus, scoticus and dewulfi are very difficult to distinguish reliably although in general scoticus females are somewhat larger and more well-marked than the others. Delecolle (1985) described differences between scoticus and obsoletus based on the genital sclerites of these species; in scoticus they have the inner border divergent, whereas in obsoletus the inner borders are more or less parallel. The sclerites of dewulfi do not seem to differ greatly from those of obsoletus. Females of obsoletus could be mistaken for a vaguely marked impunctatus, but the palp in obsoletus bears a single small sensory pit whereas in impunctatus there are several small, superficial pits. Males of these other species may be easily separated by the form of the ninth sternite.
It is a common man-biting pest and may rival impunctatus in numbers; and it is also an important pest of livestock. The survival of females of this group has been investigated by Birley & Boorman (1982), and an individual survived for three months in the laboratory (Boorman, personal observation). It has been bred from horse dung and from compost heaps, but not from cow dung. In the south of the U.K. the occasional female may be taken even during the winter months, although it probably mainly overwinters as a larva. It is one of the first species to appear in the spring. Dzhafarov (1964) gives data on its biology and times of flight, and reports larvae from tree holes and amongst moist forest leaf litter.
From Britain through Europe and Scandinavia to Russia and Japan, and from Morocco through North Africa to Israel.
Bluetongue virus was isolated from C. obsoletus midges taken in Cyprus (Mellor & Pitzolis, 1979), and African horse sickness virus has been isolated from a mixed pool of this species and pulicaris group midges in Spain (Mellor et al. 1990). More recently, bluetongue virus has been isolated from C. obsoletus group midges in Italy, and may be involved in the transmission of this virus over several countries to the north of Italy (Savini et al., 2003). It thus constitutes a potential vector of these viruses throughout the Mediterranean area and the rest of its range. It can cause an allergic response to its bite in sheep and goats; Connan & Lloyd (1988) report the bites of this species as the probable cause of allergic dermatitis in sheep, and Anderson et al. (1991) report its bites as a cause of Culicoides hypersensitivity in British Columbia.
British Culicoides
Contents | Introduction | References
back to main site | Arbovirology Modelling and Entomology
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