Monitoring bluetongue virus vectors in Andalusia (SW Europe): Culicoides species composition and factors affecting capture rates of the biting midge Culicoides imicola.

In this work, we summarize the results of captures of Culicoides species in Andalusia (S Spain) during 2007-2008. Four out of the 15 midge species-Culicoides imicola, Culicoides obsoletus complex, Culicoides pulicaris complex, and Culicoides nubeculosus-accounted for 80.7 % of captures (n = 68,190). Captures were seasonal and mostly occurred in May-November. The overall number of Culicoides specimens captured and the mean number of caught per trap were higher in 2007. We used an information-theoretic approach to analyze whether environmental factors (e.g., weather, altitude above the sea level, distance of the trap from the ground, distance to animals, and land use) affected C. imicola capture probability and success. Mean temperature and rainfall (both integrated into the Gaussen index), distance of traps to host animals, and trap height above the ground were the main factors explaining variance in capture rates in the Bluetongue Entomologic Surveillance Andalusian Program (BESAP). However, all of these patterns strongly varied among traps. As previously remarked by other authors, standardized capture methods and protocols for trap use are needed to ensure that results obtained in different geographical areas and/or periods are comparable.