关键词: 烟草甲, 低温, 亚致死时间, 年龄-龄期生命表

Abstract:  【Aim】 Low temperature is one of the key methods for controlling the important tobacco storage pest Lasioderma serricorne in China, yet the population dynamics and resistance mechanism of L. serricorne to low temperature remains largely unexplored. Examining the sublethal impacts of low temperature exposure on insects could help us understanding their adaptive responses to low temperatures. This study aims to reveal the adaptive capacity of L. serricorne  to low temperature and its population development potential under such conditions by analyzing the life table parameters of L. serricorne  offspring affected by sublethal low temperature exposure. 【Methods】To construct the time-mortality curve, we exposed the last instar larvae ofL. serricorne to -20 ℃ for different time. Using this data, we calculated the lethal time for 10% and 50% mortalities (LT₁₀ and LT₅₀). Later, we constructed the age-stage, two-sex life tables for the survived F₁ population by exposing the last instar larvae of the F₀ generation of L. serricorne  to -20 ℃ for LT₁₀ and LT₅₀, respectively. 【Results】The LT₁₀ and LT₅₀ values of the low temperature of -20 ℃ to the last instar larvae ofL. serricorne  were 5.32 and 12.84 min, respectively. More than 90% of the F₁ individuals originated from the F₀ population exposed to -20 ℃ for LT₁₀ and LT₅₀ survived and completed the whole life cycle. No significant differences in the total longevity from egg to adult, female adult longevity, net reproductive rate (R₀), intrinsic rate of increase (r_m) and finite rate of increase (λ) were found between the control population reared at 28 ℃ and the F₁ populations from the F₀ populations exposed to -20 ℃ for LT₁₀ and LT₅₀. However, compared to the control, exposure of the last instar larvae of the F₀ generation to the low temperature of -20 ℃ for LT₁₀ and LT₅₀ significantly reduced the initial life expectancy of eggs and the 1st instar larvae, the 1st instar larval duration and the reproductive value of the whole larval stage of the F₁ population, but increased the proportion of males in the F₁ population.【Conclusion】Exposure of the last instar larvae ofL. serricorne  to -20 ℃ for LT₁₀ and LT₅₀ leads to decrease in the initial life expectancy and population reproductive rate of the F₁ offspring. However, the population structure and the basic life table parameters remain normal. The results indicate thaL. serricorne  larvae have good adaptability to low temperatures, and the surviving individuals can quickly expand the population after undergoing low temperature treatment.

Key words: Lasioderma serricorne, low temperature, sublethal time, age-stage life table