Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Impact of polymorphism and abiotic conditions on prey consumption by Harmonia axyridis.

Abstract

Polymorphic diversity, such as elytra patterns of insects, is regarded as an external phenotypic characteristic driven by both genetics and environmental pleiotropy. The multicolored Asian ladybird, Harmonia axyridis (Coleoptera: Coccinellidae), both an efficient natural enemy of herbivores and an invasive species with a worldwide distribution, shows a multitude of elytral patterns and strong environmental adaptability. Some studies have documented differences of ecological adaptability among H. axyridis morphotypes, but none compared their predatory performance under differing environmental conditions, to further understand the evolutionary significance of elytral pattern diversity. We evaluated predation (number of prey consumed per time unit) on three different herbivores by melanic/succinic and male/female adults of H. axyridis, under different temperatures (10, 15, 20, 25, 30, 35°C). and photoperiods (4:20, 8:16, 12:12, 16:8, 20:4). We found significant differences in prey consumed by the predator between gender and polymorphic types, including under comparable environment parameters. Furthermore, there were also significant differences in predation when temperature and photoperiod regimes varied. Our results hinted a high plasticity in prey consumption relative to polymorphic type and gender in H. axyridis. These findings could be informative for developing further biological control programs relying on H. axyridis, notably for optimizing the effectiveness of predator releases according to polymorph to be used and environment targeted.