THE GENETICS OF PHENOTYPIC PLASTICITY IN A COLONIZING POPULATION OF THE LADYBIRD BEETLE, HARMONIA AXYRIDIS

摘要

We investigated the degree to which families of a colonizing ladybird beetle, Harmonia axyridis, differed in their phenotypic responses to familiar vs. novel food types using a split-brood full-sib design. Development time, adult size, and two measures of colour were significantly affected by diet. All traits measured were under some degree of genetic control. Significant levels of genetic variation existed in phenotypic plasticity for development time and adult size, but not for two measures of colour. Genetic correlations were found between several traits within single environments but no significant cross-environment genetic correlations were detected. We concluded that: (1) plasticity in development time and adult size may evolve given appropriate selection pressure; (2) plasticity in the two measures of colour cannot evolve owing to a lack of genetic variation; and (3) colonization of H. axyridis is associated with plasticity, though it is not clear that colonization events actively select for change in levels of plasticity. [References: 34]