Variabilité spatiale des captures de Culicoides dans des fermes de la zone de Bala au nord du Pays de Galles

Résumé

The aim of this study was to investigate the spatial variability of Culicoides catches at a local scale using environmental data and farm characteristics. A thrice-replicated random sampling design was set up on a 1x1 km grid in a 6x6 km study site in Bala, North Wales in July 2008 over a period of 12 days using Onderstepoort black light traps to catch Culicoides. Overall, 132 catches were made on 35 farms, 32 of which were sampled three times and three of which were sampled daily. A total of 357,229 Culicoides encompassing 19 species (mean catch = 2706 per trap and per night; maximum catch = 65,763) were caught. The species of the Obsoletus complex accounted for 62% of the catches. Environmental factors (such as land cover, land use, soil type, altitude and weather) and farm characteristics (animals, insecticide use, dung management, proximity to water and to potential breeding sites, and openness of the landscape) will be used to model the abundance of Culicoides species. The influ­ence of Culicoides abundance in neighbouring farms will also be assessed and accounted for. This will help better understand spa­tial distribution and variability of Culicoides densities at a local scale and provide elements for discussion on how to approach mapping and modelling of vector abundance at coarser scales.