Age-grading the biting midge Culicoides sonorensis using near-infrared spectroscopy


Dr. F. E. Dowell, USDA-ARS Center for Grain and Animal Health Research, Engineering and Wind Erosion Research Unit, 1515 College Avenue, Manhattan, Kansas 66502, U.S.A. Tel.: +1 785 776 2753; Fax: +1 785 537 5550; E-mail:


Age-grading of insects is important in the control and monitoring of both insect populations and vector-borne diseases. Microscopy and morphological techniques exist to age-grade most blood-feeding flies, but these techniques are laborious, often destructive to the insects, and slow. Near-infrared spectroscopy (NIRS) can be automated and is a non-destructive technique for age-grading. We applied NIRS techniques to age-grade females of the biting midge, Culicoides sonorensis Wirth & Jones (Diptera: Ceratopogonidae), the vector of bluetongue and other arboviruses in North America. Female flies of five known age cohorts (1, 3, 6, 9 and 12 days post-emergence) from three laboratory colonies were used. The data indicate that NIRS can be used to differentiate age groups of C. sonorensis.