二化螟的多次交配及其对雌蛾产卵量的影响

【目的】利用性诱防控和监测水稻二化螟Chilo suppressalis的有效性在田间已经得到认可。但雄蛾具有多次交配能力,致使性诱防治二化螟的应用策略一直存在争论。本研究的目的是探索二化螟雄蛾的多次交配及其对雌蛾繁殖力的影响,认识性诱防控害虫的机理。【方法】利用行为学方法调查了雌雄蛾以不同比例配对(1∶1, 4∶1和10∶10)时雄蛾的交配次数和交配持续时间,并结合解剖学方法,观察分析了二化螟雄蛾的交配次数对精巢、交配囊和精包大小以及雌蛾产卵量的影响。【结果】二化螟雌雄蛾按1∶1配对时,交配雄蛾和多次交配雄蛾的比例分别为74.0%和36.0%,平均交配1.7次,首次交配主要发生在0-1日龄,绝大部分具有多次交配能力的雄蛾的首次交配发生在0-1日龄。雌雄蛾按4∶1配对时,交配雄蛾和多次交配雄蛾的比例分别为69.4%和51.3%,平均交配2.1次,显著高于按1∶1配对。雌雄蛾按10∶10配对时,交配雄蛾和多次交配雄蛾的比例分别为65.5%和37.8%,平均交配1.9次。雄蛾第3次交配的持续时间显著长于第1和2次交配,但是交配1-3次雄蛾的精巢体积无显著差异。与不同交配次数雄蛾进行交配的雌蛾交配囊和精包体积无显著差异,雌蛾产卵量也无显著差异。【结论】二化螟中仅有部分雄蛾能够多次交配,多次交配雄蛾的首次交配主要发生在0-1日龄,部分雄蛾一生都不会交配。研究结果为二化螟的性诱防治提供了理论依据。

Multiple mating of Chilo suppressalis (Lepidoptera: Pyralidae) and its effect on the oviposition of female moths

【Aim】 The effectiveness of controlling and monitoring the striped rice stem borer, Chilo suppressalis, by pheromone trapping had been verified in the field. However, since the male moth can mate multiple times, the mass trapping control strategy of C. suppressalis has been in debate for decades. The purpose of this study is to explore the mating frequency of male moths of C. suppressalis and its effect on the fecundity of female moths, and to understand the mechanism of pest control by pheromone mass trapping. 【Methods】 The mating frequency and duration of mating of male moths of C. suppressalis paired in different female to male ratios (1∶1, 4∶1 and 10∶10) were investigated by behavioral methods. The effects of mating frequency on the size of testis, bursa copulatrix and spermatophore and the number of eggs laid by female moths were observed and analyzed by behavioural and anatomical methods. 【Results】 When the female and male moths were paired in the 1∶1 ratio, the proportions of male moths mating at least once and mating multiple times were 74.0% and 36.0%, respectively, and the average mating frequency of male moths was 1.7 times. The first mating was always found in the male at the 0-1-day-old. Most of the male moths mating multiple times were firstly mated at the 0-1-day-old. When the female and male moths were paired in the 4∶1 ratio, the proportions of male moths mating at least once and multiple times were 69.4% and 51.3%, respectively, and the average mating frequency was 2.1 times, which was significantly higher than that of male moths paired with females in the 1∶1 ratio. When the female and male moths were paired in the 10∶10 ratio, the proportions of male moths mating at least once and multiple times were 65.5% and 37.8%, respectively, and the average mating frequency was 1.9 times. The duration of the 3rd mating of males was significantly longer than that of the 1st and the 2nd mating, but there was no significant difference in the testicular volume among males mating once, twice and thrice. There was no significant difference in the volume of bursa copulatrix and spermatophore of female and in the number of eggs laid per female, which mated with males at different mating frequencies. 【Conclusion】 Only a portion of C. suppressalis male moths can mate multiple times and their first mating mainly occurred at the 0-1-day-old. A significant number of male moths do not mate in their life. Our results provide a theoretical basis for controlling C. suppressalis with pheromone trapping.