Impacts of climate, host and landscape factors on Culicoides species in Scotland

Abstract

Culicoides biting midges (Diptera: Ceratopogonidae) vector a wide variety of internationally important arboviral pathogens of livestock and represent a widespread biting nuisance. This study investigated the influence of landscape, host and remotely-sensed climate factors on local abundance of livestock-associated species in Scotland, within a hierarchical generalized linear model framework. The Culicoides obsoletus group and the Culicoides pulicaris group accounted for 56% and 41%, respectively, of adult females trapped. Culicoides impunctatus Goetghebuer and C. pulicaris s.s. Linnaeus were the most abundant and widespread species in the C. pulicaris group (accounting for 29% and 10%, respectively, of females trapped). Abundance models performed well for C. impunctatus, Culicoides deltus Edwards and Culicoides punctatus Meigen (adjusted R(2) : 0.59-0.70), but not for C. pulicaris s.s. (adjusted R(2) : 0.36) and the C. obsoletus group (adjusted R(2) : 0.08). Local-scale abundance patterns were best explained by models combining host, landscape and climate factors. The abundance of C. impunctatus was negatively associated with cattle density, but positively associated with pasture cover, consistent with this species' preference in the larval stage for lightly grazed, wet rush pasture. Predicted abundances of this species varied widely among farms even over short distances (less than a few km). Modelling approaches that may facilitate the more accurate prediction of local abundance patterns for a wider range of Culicoides species are discussed.

A first estimation of Culicoides imicola and Culicoides obsoletus/Culicoides scoticus seasonality and abundance in Europe

“…For more temperate species, Baldet et al (2008) did not observe any activity outdoors when the maximum temperature fell below 10.8 C and the minimum temperature below 5.8 C. Purse et al (2011) and Scolamacchia et al (2014) found that the best performing models based on a single set of predictors were climate models, followed by landscape and then host models. The main climatic factors that influence distribution, abundance and seasonality of Culicoides spp.…”

Comparison of single- and multi-scale models for the prediction of the Culicoides biting midge distribution in Germany

“…1 km, Kluiters et al, 2013) or at different scales (e.g. between 1 and 8 km, Calvete et al, 2008;Purse et al, 2011). However, as previously shown (Hamer and Hill, 2000), the selection of the spatial scales affects the outcome of the modelling, e.g.…”

“…Since the availability of digital datasets of land cover, temperature, or potential hosts is continuously increasing, several studies have also used this kind of data to predict the prevalence of biting midge species, e.g. the normalised difference vegetation index (NDVI) (Purse et al, 2004;Calvete et al, 2008;Kluiters et al, 2013) or the CORINE land cover data (Kirkeby et al, 2009;Purse et al, 2011). These data are available or used on different scales raising the question, which spatial scale, or scales, should be chosen to reach the best possible predictions for different biting midge species.…”

“…Although there is huge lack of knowledge about the causal connection between environmental variables and the distribution of biting midges, several studies modelled biting midge distribution and phenology using different sets of environmental data (e.g. Purse et al, 2004Purse et al, , 2011Calvete et al, 2008;Kluiters et al, 2013). These modelling approaches used environmental data from various scales, e.g.…”

Comparaison des populations deCulicoidesLatreille 1809 (Diptera : Ceratopogonidae) présentes au sein d’une bergerie belge et d’une prairie ovine associée

“…Zimmer et al (2009) avaient également observé cette même espèce au sein d'une prairie bovine mais pas dans l'étable correspondante. L'espèce C. punctatus, récemment identifiée comme un vecteur possible du SBV (Larska et al 2013) et dont l'abondance semble notamment corrélée à la présence de moutons (Purse et al 2012), est relativement bien représentée en prairie ovine (8,8% du total des captures) mais aucun spécimen n'a été observé dans la bergerie ; cela pourrait s'expliquer par la localisation des gîtes larvaires. Le nombre de spécimens de l'espèce C. chiopterus est quant à lui probablement sous-estimé, comme démontré par Carpenter et al (2008b) pour les piégeages lumineux, puis confirmé par Griffioen et al (2011).…”