Influence of prey quality on the fitness of two phenotypes of <i>Harmonia axyridis</i> adults

Abstract

Abstract The performance of Harmonia axyridis Pallas (Coleoptera: Coccinellidae) adults of the aulica and nigra phenotypes fed on Aphis fabae Scopoli and Myzus persicae (Sulzer) was compared by measuring their voracity, daily biomass consumption, daily weight gain, efficiency of food utilisation, and reproductive capacity. Our results demonstrated differences in the suitability of A. fabae and M. persicae for the two phenotypes of the predator. This suggests that either differences occur in the nutritive requirements of the predators, or in the nutritive value of the two prey species. Both A. fabae and M. persicae supported the growth and oviposition of the aulica and nigra phenotypes. Although nigra females consumed fewer M. persicae , they achieved the same daily weight gain as aulica females. The predator phenotypes consumed the same amount of A. fabae , but the daily weight gain of aulica females was higher than that of nigra . The two predator phenotypes had the same feeding efficiency when consuming M. persicae or A. fabae . The reproductive capacity of nigra females was higher, when this phenotype consumed A. fabae rather than M. persicae .