Dissecting the sterility phenotype in gene edited Drosophila suzukii pgSIT males

Drosophila suzukii is an invasive pest that affects many fresh, soft-skinned fruits such as strawberries and blueberries. To combat this pest, growers use various methods including insecticide sprays, biological control, and sanitation practices. However, these methods are becoming increasingly ineffective against D. suzukii due to increased resistance against insecticides and increasing labor costs. Sterile Insect Technique (SIT) has been used successfully to control many agricultural pests, but the use of irradiation, sex sorting, and the requirement to scale these insects make it costly to implement. pgSIT (precision guided Sterile Insect Technique) is a novel and efficient way to generate sterile males through genetic engineering and overcomes the drawbacks of traditional SIT. pgSIT has been implemented in multiple Dipteran insects, including D. suzukii, and has been shown to suppress wild insect populations. To further characterize sterile pgSIT males, we evaluated their fertility capacity, lack of mature sperm, and ability to induce a mating refractory period in D. suzukii wildtype females. In this study, we found that pgSIT sterile males do not produce mature sperm and can induce a refractory mating period in wildtype females. Furthermore, sperm DNA is not detected in the reproductive tracts of pgSIT-mated female reproductive tracts. These findings further support the penetrance of the pgSIT technology in D. suzukii and provide further supporting data to governing regulatory bodies in their evaluation of this technology.