Sterilization and sperm competition in insects with reference to pest control measures using reproductive behavior.

建立了对甜瓜蝇精子囊中精子数量进行计数的方法，并利用该方法发现甜瓜蝇精子在精子囊中的寿命比目前已知的其他昆虫短。由于精子的寿命很短，随着第一次和第二次交配之间的时间延长，最后一个雄性精子受精的优先权也会增加。不仅与正常（未受辐照）雄虫交配，而且与不育（受辐照）雄虫交配也会抑制雌虫的交配。结果表明，与精子耗尽的不育雄虫交配可以抑制雌虫的繁殖；这与黑腹果蝇（Drosophila melanogaster）的情况形成鲜明对比，在黑腹果蝇中，精子存在于精子囊中是抑制生殖的必要条件。实验还表明，抑制交配是雌性的一种策略。用电子显微镜对睾丸和精囊的检查表明，灭瓜蝇项目中使用的剂量的伽马射线辐照不仅引起精子的显性致死突变，而且对显著部分精子造成生理和形态上的损伤；对今后发展不育雄虫灭虫技术具有重要意义。

Method to count the number of sperm in spermathecae of the melon fly was established, and using this method, it was found that longevity of melon fly sperm in spermathecae is shorter than that of other insects so far known. Due to this short life span of sperm, precedence of last male's sperm for fertilization rise as duration between first and second copulations increases.Not only copulation with normal (unirradiated) males but also that with sterile (irradiated) males inhibits remating of females. It was shown that copulation with sperm-exhausted sterile males can inhibit remating of females; this is contrasting to case of Drosophila melanogaster, where existence of sperm in spermathecae is necessary to inhibit remating.Experiments also suggested that the inhibition of remating is a females strategy.Examinations of testis and spermathecae with an electronic microscope showed that gamma-ray irradiation at a dose which has been used for the melon fly eradication project induce not only dominant lethal mutation in sperm but also physiological and morphological damage to the notable fraction of the sperm; an important result for future development of sterile male technique to eradicate insect pests.