Influence of prey quality on the reproductive capacity of two phenotypes of Harmonia axyridis PALLAS (Coleoptera: Coccinelidae).

Proceedings of the 8th International Symposium on Ecology of Aphidophaga : Biology, Ecology and Behaviour of Aphidophagous Insects, Ponta Delgada 1-6 September 2002.H. axyridis is a highly polymorphic ladybird beetle with a wide geographical distribution in the palearctic region. Genetic polymorphism seems to be the strategy adopted in order to face different habitats at different times. In this paper we suggest that a genotype that confers a specific elytral pattern may also confer a particular reproductive capacity when fed on single diets of essential preys such as A. fabae or M. persicae. We discuss KOMAI & HOSINO (1951) hypothesis, which predicts that the differences in the relative frequency of elytral pattern phenotypes in relation to the host plants in a same habitat could be related with specific composition of aphid populations. Our results revealed that A. fabae significantly increased reproductive capacity of nigra phenotype without affecting reproductive capacity of aulica phenotype