Suitability of diverse prey species for development of Harmonia axyridis and theeffect of container size

Abstract: Larval development time and fresh body mass of newly emerged adults are widelyused quantitative parameters characterizing food suitability. These parameters were measured inthe ladybird Harmonia axyridis with nine different aphid species. We calculated suitabilityparameter SL = m/t (mass divided by developmental time), and ranked the aphid species studiedaccordingly: Aphis philadelphi (2.6), Aphis fabae on Rumex (2.5), Aphis spiraephaga (2.0),Acyrthosiphon pisum (1.8), Rhopalosiphum padi (1.7), Acyrthosiphon ignotum (1.6), Dysaphisplantaginea (1.5), Hyadaphis tataricae (1.4), Aphis sambuci 2009 (1.3), Aphis sambuci 2008(1.1). Conspecific eggs were moderately suitable (1.7). When larvae were reared together in 0.5lglass jars, the developmental parameters were better than when reared individually in 7 or 15cmPetri dishes in combination with most aphid species. Sexual differences in fresh mass (femalesbeing 1.1 to 1.2 times heavier) but not in developmental time were found. Some prey specieswhich are well suitable for large larvae were found not so good for young ladybird larvae due tothe large body size of these aphids.