Gamma and X-ray radiation on mating and sperm transfer in sterile Anastrepha ludens (Diptera: Tephritidae)

Ionizing radiation is widely used in insect sterilization for pest control using the Sterile Insect Technique, which consists of the mass rearing of insects and their irradiation with gamma rays to release them in target areas where they will mate with wild females. However, there is a concern and controversy about the nuclear origin applied in this technique. One alternative for sterilization is the use of X-rays, which do not have a nuclear origin, are easier to operate, and do not generate radioactive waste. Here, we compared the sexual competitiveness of Mexican fruit fly, Anastrepha ludens (Loew) (Diptera: Tephritidae) males irradiated with gamma or X-radiation, and their sperm transfer ability. Mating frequency was similar between gamma and X-ray-irradiated males, but higher for wild males. However, the amount of sperm in females mated with X-ray-irradiated males was lower than that of females mated with gamma-irradiated males. Males irradiated with X-rays, mating for a third consecutive time, transferred fewer sperm than males irradiated with gamma rays. Females mating with X-ray irradiated males were more likely to remate than females mated to gamma irradiated or wild males. Overall, males sterilized with X-rays were as sexually competitive as males sterilized with gamma radiation; however, lower sperm transfer and higher remating with females suggest the need to perform dosimetries for X ray-treated males at a lower dose to increase performance. X-rays could be used as an alternative to gamma rays in the application of the SIT for A. ludens. Further research into the effects of X-rays on the male ejaculate, female fertility, and remating is needed.