BackgroundSterile Insect Technique (SIT) has been successfully implemented to control, and in some cases, eradicate, dipteran insect populations. SIT has great potential as a mosquito control method. Different sterilization methods have been used on mosquitoes ranging from chemosterilization to genetically modified sterile male mosquito strains; however, sterilization with ionizing radiation is the method of choice for effective sterilization of male insects for most species. The lack of gentle radiation methods has resulted in significant complications when SIT has been applied to mosquitoes. Several studies report that irradiating mosquitoes resulted in a decrease in longevity and mating success compared to unirradiated males.The present study explored new protocols for mosquito sterilization with ionizing radiation that minimized detrimental effects on the longevity of irradiated males.MethodsWe tested three compounds that have been shown to act as radioprotectors in the mouse model system - ethanol, trimethylglycine, and beer. Male Aedes aegypti were treated with one of three chosen potential radioprotectors and were subsequently irradiated with identical doses of long-wavelength X-rays. We evaluated the effect of these radioprotectors on the longevity of male mosquito after irradiation.ResultsWe found that X-ray irradiation with an absorbed dose of 1.17 gy confers complete sterility. Irradiation with this dose significantly shortened the lifespan of male mosquitoes and all three radioprotectors tested significantly enhanced the lifespan of irradiated mosquito males.ConclusionOur results suggest that treatment with ethanol, beer, or trimethylglycine before irradiation can be used to enhance longevity in mosquitoes.

Abstract. Control of insect species for the protection of crops, livestock, and prevention of disease such as dengue fever and malaria is a high priority in today's global economy. Traditional methods such as pesticides have fallen out of favor because its effects are indiscriminate as well as adverse and unpredictable impacts on the environment. Modern novel techniques such as genetic modification have had trouble gaining traction due to ethics concerns and the potential for unforeseen side effects. One approach that has gained traction and has proven its efficacy is the use of ionizing radiation to affect sterility in insect species in order to scale back their population. Known as Sterile Insect Technique (SIT), it has proven very effective in eradicating certain dipteran insect populations. However, when standard sterilization methods developed for dipertans are applied to mosquito populations significant complications arise, such as an inability to compete with non-irradiated males and high mortality rates. We have investigated the effect of treatment with x-rays of different wavelengths on x-ray sterilized mosquito males. Our results have demonstrated that longer wavelength x-rays have a significant effect on the outcome of the sterile males' longevity as well as an increase on the efficacy of sterilization while employing a substantially lower dose. OVERVIEWWe have investigated the utilization of X-ray radiation to achieve sterilization for use in insect pest management programs. The denials of trans-boundary shipments of radioisotopes due to political instabilities are creating a severe constraint to sterile insect technique (SIT) programs around the world as SIT relies on the use of ionizing radiation from radioisotopes for insect sterilization. In SIT programs a large number of sterilized males are released area-wide. The sterile males compete with wild males for female insects. If a female mates with a sterile male then it will have no offspring. Ultimately, this leads to a reduction of the wild population [1]. The sexual sterility is induced with gamma radiation emitted from radioisotopes such as Cesium-137 and Cobalt-60 in almost all SIT programs. The Gammacell 220, a 60 Co irradiator (MDS Nordion International Inc., Ottawa, ON, Canada) has been the most commonly used irradiator and has proven extremely reliable for the purpose of sterilizing target insect pests. This technique has been used successfully for suppression, eradication, containment and prevention of many insect pests [2,3]. The use of sterile insects in area-wide integrated pest management (AW-IPM) programs will continue to expand as constraints are increasing on the use of chemical pesticides in relation to the public's growing demand for a cleaner environment and residue-free food.In 2006, a serious problem arose when the production of the Gammacell 220 irradiator was discontinued. The future availability of these small scale irradiators is in doubt due to growing difficulties associated with the transboundary shipment of radioisotop...