A key factor driving the huge population abundance of C. impunctatus lies in the ability of adult females to produce eggs without taking a blood meal (autogeny) ( Blackwell et al., 1992 and Boorman and Goddard, 1970). This is a selectively advantageous MEK inhibitor cancer trait in areas of low available host density, and where Culicoides larval development

sites are consistently available ( Linley, 1983). Autogeny is especially common among major nuisance species of humans, as compared to species that only take their blood meals from animals ( Isaev, 1993 and Linley, 1983). Culicoides impunctatus additionally possesses a broad host range, with evidence of feeding on a wide range of livestock and wildlife, in addition to humans ( Blackwell et al., 1995 and Blackwell et al., 1994a). The larval habitat of C. impunctatus is well defined, consisting of rush-pasture-peat communities possessing high organic and water content ( Blackwell et al., 1999 and Blackwell et al., 1994c),

created in part through tree clearance ( Hendry, 2011). In Scotland, northern England and Wales, these bog heathland ecosystems are extensively used for recreation ( Blackwell and Page, 2003), forestry and hunting, all of which can involve prolonged human exposure to biting populations of C. impunctatus. The economic impact of such attacks on tourism is thought to be significant, however, quantitative assessments of tolerance of individuals visiting these regions have not been carried out to date.

However, anecdotal estimates MK2206 from studies carried out in the Caribbean estimate that biting rates greater than 5/h may be sufficient to impact tourist behavior ( Linley and Davies, NADPH-cytochrome-c2 reductase 1971). Disruption of forestry in Scotland by C. impunctatus has been investigated, and is estimated in some areas to lead to the loss of approximately 20% of summer working days through persistent attacks during chainsaw refueling and rest breaks in the forest districts of Kintyre, Lochaber and Wester Ross ( Hendry and Godwin, 1988). A majority of common and abundant mammalophilic Culicoides species in Europe have also occasionally been recorded biting humans and these studies have been significantly expanded with the recent advent of reliable polymerase chain reaction based assays for host differentiation ( Garros et al., 2011 and Santiago-Alarcon et al., 2012a). These species include all the primary vectors implicated in transmission of livestock arboviruses in this region: C. obsoletus, C. scoticus, C. dewulfi, C. chiopterus, C. pulicaris and C. punctatus ( Dzhafarov, 1964, Overgaard Nielsen, 1964, Santiago-Alarcon et al., 2012b, Service, 1971 and Szadziewski and Kubica, 1988), with the notable exception of the major Afrotropic vector C. imicola.