Phenology and attraction of potential Culicoides vectors of bluetongue virus in Basque Country (northern Spain)

Abstract

Bluetongue virus is transmitted by Culicoides biting midges (Diptera: Ceratopogonidae). Culicoides associated with livestock were captured using CDC blacklight traps at three BTV-infected farms in Basque Country between November 2007 and December 2008. Twenty-seven and nineteen Culicoides species were collected in outdoor and indoor habitats respectively. Indoor insect community represented 86.1% of the whole captured individual biting midges. Culicoides obsoletus/Culicoides scoticus (two sibling species of the Obsoletus complex) were dominant throughout all months and sexes with maximum phenological peaks in November 2007 and June–July 2008. Culicoides lupicaris was the second most dominant species followed by Culicoides pulicaris (both species of the Pulicaris complex). Few specimens of Culicoides imicola, the principal Afro-Mediterranean vector of BTV, as well as four new species recorded for the Iberian Peninsula, were also collected. BTV was detected by RT-PCR from pools of C. obsoletus/C. scoticus, C. lupicaris and C. pulicaris parous females. dl-Lactic acid significantly attracted more C. obsoletus/C. scoticus females and males, C. lupicaris females, C. pulicaris females and Culicoides punctatus females and males; whereas acetone increased only the captures of Culicoides achrayi.