Investigating flight ability and dispersal distance of Cydia pomonella moth in northeast China to assess the side effects of X-ray Irradiation

Abstract

Abstract The codling moth Cydia pomonella (L.) is a highly destructive pest that causes considerable damage to pome fruits and walnuts worldwide. In Canada, the sterile insect technique (SIT) has proven to be an effective method for controlling C. pomonella population. However, the sterilization process, which involves exposing male moths to gamma radiation or X-rays, may result in a decrease in their mating competitiveness, likely due to a decline in their flight capacity. The impact of X-ray irradiation on the flight ability of sterilized male C. pomonella remains uncertain. In this study, we first examined the flight rhythm of male and female adults of C. pomonella. The findings revealed a significant variations in the average flight speed of both male and female moths at different stages of maturity, with females exhibiting longer flight durations and distances. Since male moths are primarily utilized in SIT programs, we focused on assessing the effect of irradiation on the flight performance of 3-day-old male moths, as they demonstrated the longest flight distance. The results indicated a significant decrease in flight performance, including flight distance, duration, and average speed, among males exposed to radiation at a dose from 183 Gy to 366 Gy. Moreover, an irradiation dose of 366 Gy caused wing deformities, limiting the dispersal distance of moths in orchards according to the mark-and-recapture assay. Further quantitative reverse-transcription PCR (RT-qPCR) analysis revealed down-regulation of flight-related genes such as flightin, myosin heavy chain, and distal-lessfollowing radiation exposure. Taken together, these findings demonstrate that X-ray irradiation at a radiation dose higher than 183 Gy adversely affects the flight ability of male C. pomonella adults. These insights not only enhance our understanding of how radiation sterilization diminishes the mating competitiveness of male moths but also contribute to the development and improvement of SIT practices for the effective control of C. pomonella.