性比对草地螟生殖潜力和寿命的影响
Effect of sex ratio on the reproductive potentials and longevity of the beet webworm, Loxostege sticticalis
李敏敏1** 程云霞1 肖永红1，2 罗礼智1*** 江幸福1 张 蕾1
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DOI：10.7679/j.issn.2095-1353.2014.189
作者单位：1. 中国农业科学院植物保护研究所，植物病虫害生物学国家重点实验室，北京 100193；2. 井冈山大学生命科学学院，江西 343009
中文关键词：草地螟，性比，交配力，产卵期，繁殖力
英文关键词：Loxostege sticticalis, sex ratio, mating capacity, lifetime fecundity, longevity, population dynamics
中文摘要：
【目的】 探明性比对草地螟Loxostege sticticalis L.种群繁殖的影响，为预测预报提供科学指导。【方法】 室内条件（温度（22±1℃，相对湿度70% ± 5%，光周期16L︰8D）下，研究了草地螟成虫雌雄比例（♀︰♂=1︰3，1︰2，1︰1，2︰1，3︰1）对主要繁殖参数和寿命的影响。【结果】 草地螟成虫的产卵前期随着雌蛾比例的增大而延长；性比为1︰1时雌蛾的产卵同步性最高；雌蛾的交配次数、产卵量以及最终孵出的后代幼虫量在不同性比组之间差异变化不大，而雄蛾的交配次数、对后代的贡献量却随着雌蛾比例的加大而显著增加，而当雌雄比为3︰1时，雌雄蛾的寿命均显著下降；在雌雄比为3︰1的条件下，雄蛾的交配次数以及对后代的贡献量均为雌蛾的2倍左右。【结论】 性比对草地螟雌蛾生殖影响较小，而对雄蛾生殖的影响较大。在雌成虫比例较低（性比为1︰3）的情况下，雄成虫的交配和生殖能力不能得到充分发挥，进而造成种群生殖资源的浪费。根据雌雄成虫交配潜力及对后代贡献量的比较分析，可以推测性比为2︰1至1︰1时，有利于草地螟大发生种群的形成。
英文摘要： [Objectives] To understand the effects of sex ratio on the reproduction of Loxostege sticticalis, thereby improving our understanding of its biology and ability to forecast outbreaks of this species. [Methods] Reproductive parameters were studied under different sex ratios (♀︰♂=1︰3; 1︰2; 1︰1; 2︰1; 3︰1) under laboratory conditions (temperature (22±1)℃, RH70%±5%, photoperiod 16 L︰ 8 D). [Results] Sex ratio had an obvious impact on L. sticticalis reproductive parameters. The results show that the pre-oviposition period of female L. sticticalis increased with increasing sex ratio. The period of first oviposition in the 1︰1 group was the highest among the five sex ratio groups. Female reproductive parameters such as mating time, egg production and number of hatchlings did not vary much among the different sex ratio groups, but those of males increased rapidly with increasing sex ratio. Both male and female longevity were significantly lower at a sex ratio of 3︰1. Males’ maximum mating time and number of offspring were about twice those of females at sex ratios of 1︰3 and 3︰1. [Conclusion] Sex ratio had little influence on the reproductive parameters of female adults compared to those of males; a 1︰3 sex ratio appeared to significantly reduce males’ mating ability and reproductive capacity. Analysis of adults’ mating potential and fecundity suggests that a sex ratio of 2︰1 is optimal with regard to the most efficient use of resources, whereas a sex ratio of 1︰1 is the best for population growth.