关键词: 异色瓢虫, 冷驯化, 母代效应, 适合度, 生命表参数, 两性生命表

Abstract: In order to clarify the effects of cold acclimation on development and fitness of Harmonia axyridis (Pallas) offsprings, based on age-stage, two-sex life tables, we investigated the developmental duration, pre-oviposition period, fecundity, adult 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 (λ), the net reproduction rate (R₀) and the age-specific survival rate (l_x) 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 l_x 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.

Key words: Harmonia axyridis, cold acclimation, maternal effects, fitness, life table parameters, two-sex life table