Flight Performance, Fecundity, and Ovary Development of Grapholita molesta (Lepidoptera: Torticidae) at Different Ages

SIMPLE SUMMARY: New environment-friendly strategies, such as the sterile insect technique (SIT), are urgently needed to manage populations of Grapholita molesta, a serious fruit pest. When mass-rearing the insect in a factory, assessments of various appropriate quality control parameters are essential. Flight ability, fecundity, and ovarian development are critical quality control parameters to be measured for moths being mass-produced. In this study, we found that that the flight performance, fecundity, and ovarian development of G. molesta moths changed with age. The fecundity of G. molesta at different ages was closely related to the ovarian development. G. molesta females began to lay eggs in large numbers from the third day after emergence. It is suggested that three-day-old males are the best option for releasing G. molesta for SIT. When mass-rearing and keeping the population of the moth in factory, female moths older than three days can be used for egg-laying. ABSTRACT: Grapholita molesta is one of the most serious pests in fruits orchards. Flight performance of male insects and fecundity of female insects are important quality control parameters when moths are mass-reared for use in environment-friendly control strategies such as the sterile insect technique (SIT). However, information about flight performance, fecundity, and ovary development of G. molesta at different ages is scarce. In this study, we used a flight mill information system to measure the flight ability of female and male adults of G. molesta at different ages, and evaluated fecundity and ovarian development of female adults at different ages. The results demonstrated that the flight parameters (cumulative flight distance, cumulative flight time, maximum flight distance and maximum flight duration) of female and male G. molesta varied with age. Six-day-old female moths and three-day-old male moths were the strongest fliers, whereas the fecundity of one-day and two-day-old female moths was significantly lower than that of three to seven-day-old females. Five-day-old females had the highest fecundity. Their ovaries demonstrated mature eggs in the lateral and middle oviducts as of the third day post-emergence. It is suggested that the optimal age for moths to be released in SIT programs is three days, and moths older three days can be used for mass-rearing in a factory.