Intraguild Predation Behaviour of Ladybirds in Semi-Field Experiments Explains Invasion Success of Harmonia axyridis

摘要: Harmonia axyridis has been introduced as a biological control agent in Europe and the USA. Since its introduction, it established spread, is now regarded an invasive alien species. It suggested that intraguild predation especially important for invasion success of H. axyridis. The aim this study was to compare behaviour three ladybird species (Coccinella septempunctata, Adalia bipunctata, axyridis). Predation investigated semi-field experiments on small lime trees (Tilia platyphyllos). Two fourth-instar larvae placed tree rarely made contact during 3-hour observations. When together single leaf 23%–43% observations at least one made. Of those contacts 0%–27% resulted attack. attacked mostly heterospecifics, while A. bipunctata C. septempunctata heterospecifics often conspecifics. In comparison with most successful predator won 86% 44% heterospecific battles against respectively, whilst none only bipunctata. Coccinella dropped from earlier more than other two but some cases able return tree, under cloudy conditions. frequency which did not depend larva paired with. results these confirm strong consequence aggressiveness good defence fact such helps explain establishment