冷驯化对异色瓢虫后代生长发育及适合度的影响

Effects of cold acclimation on developmental characteristics and fitness of Harmonia axyridis (Coleoptera: Coccinellidae) offsprings

为明确冷驯化处理对异色瓢虫Harmonia axyridis后代生长发育及适合度的影响,本研究通过两性生命表的制作,在室内条件下调查了冷处理后其后代发育历期、成虫产卵前期、寿命和生殖力以及后代生命表参数。结果表明:冷驯化使异色瓢虫后代卵的发育历期延长,幼虫(1-4龄)和蛹的发育历期则缩短;随着冷驯化时间的延长,后代体长和体重增量均减小。且完成发育的后代成虫产卵前期延长,寿命缩短,生殖力下降。后代生命表参数内禀增长率(r)、周限增长率(λ)、净生殖率(R0)和年龄特征存活率(lx)均降低,但是后代雌虫所占比例却升高。此外,冷驯化类型对异色瓢虫后代生长发育的影响也不相同。经相同时间(5d)的低温诱导,变温诱导的后代成虫寿命比恒定低温诱导的长,但是生殖力却低;变温诱导的后代生命表参数(r,λ和R0)均小于恒定低温诱导的,但是lx却高于恒定低温诱导的。结果说明,异色瓢虫亲代经历冷驯化,这种对低温的可塑性反应会延伸到下一代,而且还能够影响后代的适合度,这对其在低温下的存活和繁殖具有重要的意义。

In order to clarify the effects of cold axyridis （Pallas） offsprings, based on age-stage, duration, pre-oviposition period, fecundity, adult acclimation on development and fitness of Harmonia two-sex life tables, we investigated the developmental life span and population parameters of the offsprings from parental populations with cold acclimation in the laboratory condition. The results showed that for offsprings, the egg developmental period increased while the larval （1 -4 instar） and pupal durations were shortened. Variation of body length and body weight gain decreased with the duration of cold acclimation prolonged. Cold acclimation of parents could significantly delayed pre-oviposition period of the offsprings, lowered fecundity, and shortened adult life span. For population parameters of offsprings from the acclimated parental generation, the intrinsic rate of increase （r）, the finite rate of increase （A）, the net reproduction rate （R0 ） and the age-specific survival rate （lx） significantly decreased whereas the proportion of females increased. In addition, the type of cold acclimation had a dramatic impact on growth and development of offsprings, with longer longevity and higher lx for offsprings from the acclimated parental generation at the fluctuating temperature than at the constant temperature 5℃, but lower fecundity and population parameters （r,λ and R0 ）. The results suggest that plastic responses to chilling are not only realized within the parental generation but also extend across generations, which is very important for H. axyridis to survive and reproduce at low temperature.