Method of assessment of dispersal pathways. A. Clustered back-trajectories from the incursion site. B. Source region defined and putative source sites selected (stars). Dispersal from the source sites at dusk and dawn assessed. Dispersal to Kalumburu (triangle) on 16 March 2012 is shown in this figure. The relative numbers of dispersed Culicoides are represented by the colours in the dispersal figure.