Prey selection by the lady beetle Harmonia axyridis: the influence of prey mobility and prey species

Abstract

The influence of prey mobility and species on prey selection by the coccinel-lid Harmonia axyridis Pallas was determined under laboratory conditions for two prey species, Hyaliodes vitripennis (Say) and Tetranychus urticae Koch. Prey selection was influenced by prey mobility. In the presence of ac-tive prey, the coccinellid selected T. urticae while in presence of immobilized prey, H. vitripennis was preferred. Harmonia axyridis searching time was longer in the presence of active H. vitripennis than in the presence of ac-tive T. urticae. Moreover, the coccinellid capture rate was lower for active H. vitripennis caused by effective defensive mechanisms. Prey suitability was affected by prey mobility and species. Immobilized H. vitripennis were the most profitable prey, i.e. induced a shorter developmental time and no mor-tality. However, active H. vitripennis were not a suitable food source for H. axyridis. Our results suggested that three factors are involved in prey selec-tion by H. axyridis: (i) prey mobility; (ii) prey defensive mechanisms; and (iii) prey species. KEY WORDS: foraging behavior; prey selection; prey mobility; defensive mechanisms; intraguild predation