Abstract: In order to identify and analysis phylogenetic relationships of the subgenus Culicoides, wing shapes were compared and analyzed by using geometric morphology method. Various geometric methods were used to analyze wing shape variation of 20 species from six subgenus Culicoides, including landmarks, centroid size, procrustes superimposition, principal component analysis, canonical variate analysis and cluster analysis. Kruskal-Wallis of centroid size results showed as follow: Avaritia>Trithecoides>Beltranmyia>Culicoides>Monoculicodie>Oecacta, but there was no significant difference, indicating the size of wings could not be used as the basis for distinguishing subgenus. Principal component analysis showed that principal component 1 (73.648%) and principal component 2 (12.372%) accounted for 86.020% of the total variation, which could explain the main difference between the wings of the six subgenera. The grid diagram showed that the differences were mainly concentrated in radial-median crossvein, basal portion, first radial cell, second radial cell and fourth medial cell. Canonical variate analysis results showed that there were significant differences in the wing shape (P<0.05), the most significant difference in the wing shape between the subgenus Monoculicodie and Trithecoides, and the smallest difference between the subgenus Beltranmyia and Oecacta. Therefore we could accurately identify the species of the different subgenus by the variation of wing shape. Cluster analysis showed that the genetic relationship between the subgenus Beltranmyia and Oecacta were the closest, between the subgenus Trithecoides and Culicoides were the second, between the subgenus Monoculicodie and Trithecoides were the farthest. This result was consistent with that of canonical correlation analysis. Geometric morphology was a useful assistant tool to study the relationship and taxonomy within the genus Culicoides.

Key words: Culicoides, wing, geometric morphometric, morphologic variation, genetic relationship