The effects of a tsetse DNA virus infection on the functions of the male accessory reproductive gland in the host fly Glossina morsitans centralis (Diptera; Glossinidae)

Freshly deposited third instar Glossina morsitans centralis larvae were inf ected with the tsetse DNA virus by microinjection, and at emergence adult m ales were separated from the females and fed on rabbit blood every second d ay for 8 days. A control group treated with sterile saline were handled sim ilarly. They were dissected, and comparative observations made on the appea rance and size of the accessory reproductive glands (ARG) in infected and c ontrol males. Regularly fed 8-day-old males from infected and control group s were mated to 2-day-old normal females obtained from the insectay. After separation from copula, the females were dissected and the uteri examined f or the presence and quality of the spermatophore. The spermathecae were als o examined for insemination. ARG tissues from the control and virus infecte d regularly fed 8-day-old male flies were fixed and processed for electron microscopic studies. The ARGs from control flies were found to be milky in appearance, whereas t hose from virus-infected flies were transparent in most parts. The ARGs fro m virus-infected males were significantly smaller in diameters (F = 42.26, p < 0.0001) and shorter (F = 200.4, p < 0.0001) than those of the controls. Most of the virus-infected males failed to form a complete spermatophore, w hereas almost all the controls formed complete spermatophore as observed in the uteri of the female mates (X-2 = 111.661, p < 0.0001). The infected ma les that formed partial spermatophores and those that did not form any at a ll failed to inseminate their female mates. Histological studies of the ARGs revealed some lesions in the epithelial ce lls characterized by degeneration of cytoplasmic organelles and detachment of the muscle layer from the basal plasma membrane. However, no virus parti cles were observed in the affected cells.