Individual variability in the parameters of growth and development in invasive and autochthonous populations of Harmonia axyridis (Pallas) (Coleoptera, Coccinellidae)

Abstract

Laboratory experiments showed that under the same constant conditions individual variability in several important parameters of the life cycle: the rate of preimaginal development, size and weight of emerging adults (largely determining the potential fecundity of females), and the rate of reproductive maturation (indirectly representing the tendency for reproductive diapause) in individuals from the laboratory strains which originated from European and Caucasian invasive populations of the predatory ladybird Harmonia axyridis is significantly higher than those in individuals from the strains which originated from autochthonous East Asian populations of the same species. This phenomenon is possibly based on high genetic diversity of the invasive populations resulting from numerous introductions and / or hybridization with individuals from laboratory strains using for biological control of pests. The high individual variability was probably one of the prerequisites for the invasion.