水稻二化螟的交配行为

在室内条件下,对水稻二化螟Chilo suppressalis的交配行为及能力进行了研究.结果表明：大多数二化螟雌蛾一生只交配一次,平均0.92次;而雄蛾具有多次交配能力,最多达4次,平均2.72次.二化螟雌蛾的日龄影响其交配率、交配起始时间和持续时间,随二化螟雌蛾日龄的增加,其交配率逐渐下降,交配起始时间逐渐提前,而交配持续时间逐渐上升.相反,二化螟雄蛾日龄对其交配率、交配起始时间和持续时间没有明显影响.交配日龄对二化螟雌蛾的生殖力也存在显著影响,随着二化螟雌蛾交配日龄的增加,雌蛾产卵量下降,卵孵化率降低,产卵期缩短,它们都与雌蛾交配日龄存在显著的负相关;而雌蛾产卵前期和雌蛾寿命随雌蛾交配日龄的增加而延长,与雌蛾交配日龄存在显著的正相关.但二化螟雄蛾交配日龄对雌蛾的生殖力没有明显影响,二化螟雄蛾一生都具有较强的交配繁殖能力.同时,不同交配史的雄蛾与雌蛾交配,对雌蛾的生殖力也没有显著影响.表明二化螟的交配活动是由雌蛾主导控制的.最后,对这些结果在二化螟性信息素防治中应用的可行性进行了探讨.在应用性信息素控制二化螟的实践中,可以在两方面取得实效,一是性信息素可以阻碍雌雄之间正常交配,降低交配率;二是可以推迟二化螟雌虫的交配,使其产卵量和卵孵化率降低.

Mating behaviour of the rice stem borer, Chilo suppressalis (Walker)

In China, the rice stem borer (RSB), Chilo suppressalis (Walker) causes (extensive rice damage and yields loss. One of compatible management strategies and methods for an integrated approach to the RSB control is to manipulate RSB's reproductive behavior, which suppression of pheromonal communication via trapping and interfering mating is a particularly common method. Therefore, it's very important to understand the mating process, the factors affecting it as well as its role in reproduction. In this study, we focused on RSB mating ability, the effects of delayed mating and male mating history on the longevity and reproductive performance of female RSB under laboratory condition. When daily paired with 2-day-old virgin males, females normally copulated only once in their whole life span. However, the mating frequency of males was much higher, 2.7 times per life span when they daily paired with 2-d-old virgin females, few males could even mate 4 times during their life span. Female age influenced mating behavior as well: the ratio of mating increased with the age and reached the maximum when females were 2 or 3 days old, then, decreased rapidly with age. The onset time of mating (time after light switched off) would start earlier with the increase of the female age, which ranged from 225.5 min to 120.0 min. However, the duration of mating prolonged as the female mating age increased. On the contrary, both the starting time and duration of mating were not significantly affected by mating age of males. In another experiment, the mating of virgin male and female RSB moths of different age groups (female 1, 2, 3, 5 and 7 d, and male 1, 2, 3, 4 and 6 d, respectively) were delayed to determine the effects of delayed mating on female longevity, preoviposition period, oviposition periods, fecundity, and egg fertility. The results indicated that female delayed mating significantly influenced the reproductive output and longevity of female RSB. Both female longevity and the preoviposition period increased as female mating age increased, showing positive correlation. When female mated on following night of eclosion, they survived for 6.3 days in average. Longevity increased as mating delayed, which females could survive for 10.2 days when their mating was prolonged for 7 days. And virgin females survived even longer, 10.6 days. However, female delayed mating had negative impact on the oviposition period, fecundity and egg fertility. The oviposition period decreased with the mating delay, depending on the mating age. Oviposition was delayed or disappeared in the absence of mating, and virgin females laid an average of 18 eggs, which indicated that mating could result in the maturation and deposition of eggs. Mean fecundity and egg fertility were 241.3 and 98.3% for the female mating in the day after emergence, and 96.2 and 75.5% for the mating at 7 day after emergence. Both were reduced significantly when mating was delayed over 5 days after emergence. The reduced fecundity and fertility with female mating delay resulted in a 69.4% decrease in the number of viable eggs laid. On the contrary, delayed mating of male had less impact on reproductive output and longevity of female RSB than that of female, no matter how long the male mating had delayed. In addition, we also studied the effect of male mating history on female reproductive output. The results showed that males with different mating history did not result in a significant difference in the quality of their contributions to females.In conclusion, the female mating delay caused more negative impact on female reproductive potential than that of male. Therefore, reducing the mating rate as well as delaying mating can help us to successfully control RSB in the field using the sex pheromone.