X-rays and gamma rays do not differ in their effectiveness for sterilizing pupae and adults of the mosquito <i>Aedes aegypti</i> (Diptera: Culicidae)

The sterile insect technique (SIT) is increasingly used as an alternative or supplemental tool in the integrated mosquito management toolbox to protect human health worldwide. SIT programs targeting mosquitoes such as Aedes aegypti (L.) have generally used high-activity isotopes of 60Cobalt or 137Caesium to sterilize males, however, these gamma irradiators pose substantial security challenges and are becoming more difficult and expensive to obtain and maintain. One practical alternative is using commercially available low-energy X-ray irradiators. In this study, we compared the efficacy of a low-energy X-ray irradiator and a traditional gamma irradiator for achieving male sterility in both male pupae and adults of the mosquito Ae. aegypti Linn. We found that both irradiators performed equivalently with 99% sterility achieved at ~50 Gy when male pupae were irradiated and ~70 Gy when male adults were irradiated. There were no differences in lifespan or male mating competitiveness at the sterilizing dose between the 2 irradiation platforms. Taken together, our results suggest that with careful dosimetry X-ray irradiators can effectively be used as an alternative to gamma irradiators in SIT programs targeting Ae. aegypti.