短时低温对马铃薯甲虫种群增长的影响

【目的】马铃薯甲虫Leptinotarsa decemlineata是我国重要的检疫性害虫，对茄科植物危害严重。本研究旨在明确出现倒春寒短时低温对马铃薯甲虫种群增长的影响。【方法】马铃薯甲虫卵在8℃下分别处理1, 3和5 d，以27℃下饲养的卵作为对照，调查卵孵化率及孵化后幼虫的生长发育和成虫繁殖情况，用种群参数评估短时低温对马铃薯甲虫种群增长的影响。【结果】马铃薯甲虫卵经8℃短时低温处理后，随着低温胁迫天数的增加，卵期显著延长；3 d和5 d处理组中卵孵化率显著低于对照，1龄幼虫发育历期显著长于对照，但8℃低温处理对2, 3和4龄幼虫历期以及蛹期均无显著影响。马铃薯甲虫卵经8℃低温处理5 d后，1龄幼虫和成虫存活率显著低于对照，而其余各发育阶段的存活率在各处理组间均无显著差异。在8℃低温处理3 d时马铃薯甲虫的内禀增长率(r)、周限增长率(λ)、净增殖率(R₀)显著低于对照和低温处理1 d时，但平均世代时间(T)在各处理组间无显著差异。【结论】短时低温胁迫对马铃薯甲虫的生长发育有不利影响，延缓和降低了马铃薯甲虫种群增长。

Effects of short-term low temperature on the population growth of the Colorado potato beetle,Leptinotarsa decemlineata(Coleoptera:Chrysomelidae)

【Aim】The Colorado potato beetle,Leptinotarsa decemlineata is an important quarantine pest in China,and it has serious harm to Solanaceae plants.This study aims to clarify the effects of late spring coldness and short-term low temperature on the growth of L.decemlineata population.【Methods】L.decemlineata eggs were exposed to low temperature of 8℃for 1,3 and 5 d,and those cultured at 27℃were used as the control,and the egg hatching rate,growth and development of larvae and adult reproduction were investigated.The effects of short-term low temperature on the population growth of Colorado potato beetles were evaluated by population parameters.【Results】When L.decemlineata eggs were exposed to low temperature of 8℃,the egg duration was significantly prolonged with the treatment time.The egg hatching rates in the treatment groups of 3 d and 5 d were significantly lower than that of the control,and the 1st instar larval duration in these two treatment groups was significantly longer than that of the control.However,the 2nd,3rd and 4th instar larval and pupal duration was not significantly affected by the low temperature treatment of 8℃.After L.decemlineata eggs were exposed to low temperature of 8℃for 5 d,the survival rates of the 1st instar larvae and adults were significantly lower than that of the control,but those of the other developmental stages in various treatment groups showed no significant difference.After L.decemlineata eggs were exposed to low temperature of 8℃for 3 d,the intrinsic rate of increase(r),finite rate of increase(λ),and net reproductive rate(R₀)of population were significantly lower than those of the control and exposed to low temperature for 1 d,but the mean generation time(T)in various treatment groups were not significantly different.【Conclusion】Short-term low temperature stress has adverse effects on the growth and development of L.decemlineata and slows down its population growth.