Comparison of the efficiency of five suction light traps under field conditions in South Africa for the collection of Culicoides species.

ABSTRACT

Culicoides biting midges (Diptera Ceratopogonidae) are involved in the transmission of a variety of pathogens, the economically most important being the orbiviruses that cause bluetongue and African horse sickness; both of which have been shown to be multi-vector diseases. The identification of all potential vectors will be crucial for the implementation of integrated control measures and disease risk analysis. The primary monitoring tools used for the collection of Culicoides midges are various models of suction light traps. In order to facilitate comparison of data between laboratories the efficiency of five traps (Onderstepoort, Rieb, mini-CDC, Pirbright, BG-sentinel), used at present and in the past in Europe, was compared in the field in South Africa. Comparisons were done either in three replicates of a 4x4 or two replicates of a 5x5 randomized Latin square design. The Onderstepoort trap collected significantly more Culicoides midges than the other traps. Relatively small but statistically significant differences were found in the species composition, parous rates, sex ratios as well as the ratio of Culicoides midges to other insects, as determined by the different traps. It will be important to determine the significance and underlying causes for these differences.