Morphometrics Studies on Females Anopheles arabiensis Patton (Diptera: Culicidae) from Kassala State, Eastern Sudan

Anopheles arabiensis Patton (1905) is the most important malaria vector in Sudan. A morphometric analysis was carried out to characterize the morphology of adult females An. arabiensis and to test the existence of morphological variations among local populationsof females An. arabiensis found in eastern Sudan.Adult females An. arabiensis were collected from four sites in Kassala State, eastern Sudan (Kassala, New Halfa, Aroma and Wager). In addition, An. arabiensis specimens, obtained from Sennar laboratory colony were also used in the study. Collection of females An. arabiensis mosquitoes was done by hand capture during  the rainy season 2008. Thirty seven morphological characters were examined on samples representing each of the collection sites. One Way ANOVA testshowed significant differences in most of the measured characters on females An. arabiensis . Principal component analysis showed that the populations studied differed mainly in the body size of mosquito. A discriminant function analysis was used, based on the new variables generated by principal component analysis, to select an aggregate of morphological characters which collectively could differentiate local populations of females An. arabiensis and to assess the reliability associated with multivariate statistics. Using the body size measurements, the analysis revealed that geographical clustering of field collected females An. arabiensis populations were not clear and the body size characters had little discrimination values. The cluster analysis summarized the phylogenetic relationships among the different populations of An. arabiensis according to their mean body sizes . Laboratory colony samples had a smaller body size compared to the field collected ones. The morphometric analysis confirmed the existence of some geographical variations in the mosquito body size among local populations of An. arabiensis in eastern Sudan.