关键词: 柑橘大实蝇, 扩散机制, 蔗糖, 蛋白, 生殖发育

Abstract: 【Aim】The aim of this study is to target the specific itinerant dispersal pattern of Bactrocera minax by investigating the nutritional requirements of B. minax adults at different ages (specific dispersal stages) for sucrose and protein, the development progress of testes and ovaries, and the dynamics of mating and oviposition of their adults at specific dispersal stages, to clarify the nutritional basis and reproductive developmental nodes in different dispersal stages of B. minax, and to rudimentarily understand its dispersal mechanisms, so as to provide a basis for precise control of B. minax adults. 【Methods】The female and male adults of B. minax at various dispersal stages consumed either sucrose or the mixed food of sucrose with yeast (sucrose∶yeast=3∶1, m/m)(the main components of yeast are protein and vitamins), and the sugar and protein requirements of adults at different dispersal stages were determined. The adult ovaries and testis were dissected, the adult mating and oviposition dynamics were observed, and the developmental basis and nodes of their initiation and diffusion were analyzed.【Results】The female adults of B. minax at the out-migrating stage (1-day-old) and the pre-return migrating stage (15-day-old) had a significantly higher sucrose consumption than those at the other dispersal stages, while those at the out-stay stage (10-day-old) had the lowest sugar consumption. At every step of the migratory process, male adults had significantly lower sucrose consumption than female adults. The 10-day-old female adults had the highest yeast consumption, while the 1-, 10- and 30-day-old male adults had significantly higher yeast consumption than the 15- and 20-day-old male adults. The 10-day-old female and male adults, 20-day-old male adults and 30-day-old male adults exhibited significantly increased consumption to the mixed food of sucrose with yeast than to single sucrose, while the 1-, 15- and 20-day-old female adults showed significantly decreased consumption to the mixed food of sucrose with yeast than to single sucrose. The consumption of male adults of each age to the mixed food of sucrose with yeast did not significantly decrease as compared with that to single sucrose. After adding yeast, the 1-, 15-, 20- and 30-day-old female adults and the 15-day-old male adults had significantly lower consumption to sucrose in the mixed food than to single sucrose. The ages of adults with 16%, 50% and 84% of the stage 3 ovaries were 9.17-, 14.80- and 20.34-day-old, respectively. The testis volume of male adults was the lowest at the 5-day-old, started to dramatically expand at the 10-day-old, and reached the maximum at the 30-day-old. The testis length increased with the male ages ranging from 10- to 20-day-old, but became obviously shortened at the 30-day-old. The testes width of male adults increased sporadically with age, with the larger ones occurring between 10- and 30-d-old. The ages of adults at the mating onset (with the cumulative mating rate of 16%), mating peak (with the cumulative mating rate of 50%) and mating end (with the cumulative mating rate of 84%) were 16.90-, 22.06- and 27.42-day-old, respectively, while those of female adults at the oviposition onset (with the cumulative oviposition rate of 16%), oviposition peak (with the cumulative oviposition rate of 50%) and oviposition end (with the cumulative oviposition rate of 84%) were 16.03-, 28.08- and 38.69-day-old, respectively. 【Conclusion】The female adults of B. minax have high demand for sucrose during the out-migrating and pre-return migrating periods, and the female adults in the migration state (out migrating stage, return migrating stages and alternately dispersal stage) have higher demand than males, meaning that sucrose is an essential nutrient for migration. B. minax has the highest protein consumption during the out-stay stage, which is consistent with the onset of ovarian development. The degree of protein demand in males corresponds to the size of the testes. Protein is closely related to the development of the adult reproductive system and can provide the nutritional basis for its migration and diffusion. The pre-return migrating stage of adult is consistent with the peak of female ovarian development and the onset of mating, indicating that the developmental status of the adult reproductive system is strongly tied to the launching node of the return migration. And the maturation of the female ovaries is the decisive physiological basis for the return migration in the populations. Therefore, the return migration phase of B. minax can be predicted by monitoring the progress of ovarian development in females.

Key words: Bactrocera minax, dispersal mechanisms, sucrose, protein, reproductive development