Fig. 1

Culicoides spp. neighbor-joining tree constructed in MEGA6 using the uncorrected p-distance. The data for the tree were cytochrome c oxidase subunit 1 (cox1) sequences from Culicoides variipennis species complex collected in Northern California and South Carolina. Branch labels are statistical support generated by 1000 bootstrap replicates. Only values greater than 50% are shown. The labels on the right are species identification based on reference samples. The scale-bar represents the average number of base pair changes per site. Only two species could be identified, C. occidentalis (A) and all other C. variipennis species complex individuals (B and C). Cluster A contained the five male reference specimens identified as C. occidentalis. Cluster B contained the female reference specimens identified as both C. sonorensis and C. variipennis. Cluster C did not contain any reference specimens. We could not differentiate C. sonorensis and C. variipennis using cox1 thus we grouped clusters B and C under the C. variipennis complex. The abbreviations for the state from which the samples were collected are to the right of each cluster. Abbreviations: CA, California; SC, South Carolina