The microhabitat ofCulicoides impunctatus(Diptera: Ceratopogonidae) larvae in Scotland

Abstract

AbstractSoil samples were taken from two transects (total 63 sampling points; 25 cm quadrats) representing theBetula pubescens(Betulaceae) woodland, rush-pasture and peat-based mire vegetation of the west coast and Highlands of Scotland, in an attempt to relate soil and vegetation features to the occurrence ofCulicoides impunctatusGoetghebuer larvae. The covers of vegetation groups were recorded at each sample site and soil wetness was assessed on an arbitrary scale.Culicoidesspp. larvae were extracted from half of each sample and stored for subsequent identification ofC. impunctatuslarvae, while the remaining half was used for analysis of soil pH and organic content (loss on ignition, LOI). Correspondence analysis (using DECORANA) separated the sample sites and vegetation groups and the ordination axes were significantly correlated with the density ofC. impunctatuslarvae, soil organic content and soil wetness index. Simple regression analyses revealed that the density ofJuncus acutiflorus/J. articulatus(Juncaceae) and soil wetness index were positively related to the overall variation inC. impunctatuslarval density. The wetness index had the strongest relationship and this remained the case in step-wise multiple regression. There was no relationship between larval density and soil pH. This information on the specific microhabitat preferences of the larvae could aid colonization attempts of this dominantly important species of biting midge in the UK.