关键词: 稻纵卷叶螟, 蛹, 高温, 热击时长, 繁殖力, 种群预测

Abstract: 【Aim】This study aims to clarify the sensitivity of pupae of the rice leaf folder, Cnaphalocrocis medinalis, to high temperature, and to provide some biological indexes and models for predicting the developmental trend of populations at the pupal stage based on temperature.【Methods】The 1-5-day-old pupae of C. medinalis were exposed once to 37, 39 and 41 ℃ for 1-7 h, and the 1-day-old pupae were exposed to 37, 39 and 41 ℃ for 1-7 h/d in consecutive 2 and 3 d. The pupae reared at 27 ℃ were used as the control group. The eclosion rates of pupae, pupal duration, numbers of eggs laid per female, and egg hatching rates of the heat shock treatment groups and control group were measured. The relationships of the eclosion rate of pupae, pupal duration, number of eggs laid per female, and egg hatching rate with the heat shock duration were established using the linear regression method. 【Results】 After a single exposure of the 1-5-day-old pupae of C. medinalis to 37, 39 and 41 ℃ for 1-7 h, the pupal duration was prolonged, and the eclosion rate of pupae, number of eggs laid per female, and egg hatching rate decreased with the temperature rising as compared with those of the control group. At the same high temperature, the pupal duration was prolonged linearly, and the eclosion rate of pupae, number of eggs laid per female and egg hatching rate decreased linearly as the heat shock duration increased, and the rates of change were almost the same among treatments for different day-old pupae. After exposure to 37 and 39 ℃, the pupal duration of the 1-day-old pupae group was longer than that of the 3-5-day-old pupae group, while the eclosion rates of pupae of the former were lower than those of the latter. After consecutive heat shock on the 1-day-old pupae under 37 and 39 ℃, the pupal duration was shortened with the heat shock duration per day increasing. Similar trend was also observed in the heat shock under 41 ℃ for 2 d, but after 3 d of heat shock under 41 ℃ for 7 h/d, the pupal duration was elongated. The eclosion rate of pupae, number of eggs laid per female, and egg hatching rate decreased linearly as the heat shock duration per day extended, with the decrease magnitude increasing with the increased temperature, but they exhibited no significant difference between 2 and 3 d of heat shock. After exposure to 37, 39 and 41 ℃ with extended 1 h/d heat shock in 2 and 3 d, the eclosion rates of pupae decreased by 3.25%, 4.95% and 7.49%, respectively, the numbers of eggs laid per female decreased by 5.02%, 7.80% and 10.82%, respectively, and the egg hatching rates decreased by 2.20%, 3.31% and 5.05%, respectively, indicating the inhibitory effect of heat shock on the population development.【Conclusion】The pupae of C. medinalis are sensitive to high temperature and heat shock affects their development, survival, and fecundity. Therefore, the population size of C. medinalis will be predicted based on the degree and duration of high temperature at the pupal stage.

Key words: Cnaphalocrocis medinalis, pupae, high temperature, heat shock duration, fecundity, population prediction