RADIATION-INDUCED STERILITY IN THE INSECT RHODNIUS PROLIXUS

Abstract

Immature fifth instar Rhodnius nymphs and adults of both sexes were exposed to various doses of 2 MVP X-rays, chosen to produce reductions in fertility up to and including complete sterility. In male insects irradiated as fifth instar nymphs and reared to the adult stage, sterilizing doses interfered with mating, thus making these males useless as a means of inhibiting the growth of populations into which they are introduced. Exposure in the adult stage, on the other hand, had less effect on mating behavior. Thus, with a very high dose (17,500 r) and high ratios of sterile to fertile males, a substantial reduction occurred in percentage of viable eggs from normal females. However, this was true for the first month only. In the second and third months, the effect on population fertility disappeared, a result of the early deaths of irradiated males. Greater effectiveness in limiting population growth over extended periods might be expected to result from the introduction of males that had been partially sterilized by exposure to lower doses.