Printed in Great Britain The effect of X-radiation on spermatogenesis and the fertility of

Normal spermatogenesis and the effects of X-radiation on the male locust germ cells have been studied with the aid of light and electron microscopy. Adult insects were irradiated with doses of 100-500 rad (i.e. 1-5 J kg"1) and subsequently examined, at intervals, up to 55 days later. In secondary spermatogonia all doses caused nuclear fragmentation and necrosis, and in primary spermatogonia and a few spermatocytes caused a delay in division. Spermatids and the majority of spermatocytes developed into spermatozoa which were passed from the follicles to the seminal vesicles. The supply of sperm was, subsequently, temporarily stopped. The follicles were eventually repopulated by the division of the primary spermatogonia. Radiation-induced abnormalities, e.g. the formation of supernumerary centrioles, flagella and definitive mitochondria, were most common in the cytoplasm. The Golgi bodies and acrosome seemed to be unaffected. Abnormal outgrowths of the late spermatid and sperm nuclei appeared to be caused by the presence of the numerous centrioles and flagella. The bright yellow coloration of the cuticle, which is characteristic of sexually mature males, was not fully developed in irradiated males. Breeding experiments showed a significant reduction, when compared to the controls, in the number and percentage hatchability of eggs obtained from females mated to irradiated males. The doses of radiation employed did not appear to affect the longevity of the adults