Temporal and climatic variation in the colour forms of Adalia bipunctata and Harmonia axyridis (Coleoptera: Coccinellidae) populations in the United Kingdom

Abstract

The invasion success of H. axyridis is largely due to a range of physiological adaptations, typical of invasive non-native species, that allow it to colonise, disperse, and outcompete native species extremely effectively (Majerus et al., 2006). Competition with H. axyridis has been suggested as an explanation for the rapid decline of Adalia bipunctata (Linnaeus, 1758) throughout its native range in North America, Belgium, and Britain (Harmon et al., 2007; Roy et al., 2012). Adalia bipunctata is just one of the many coccinellids adversely impacted by the invasion of H. axyridis, however, it has been one of the most severely affected (Brown et al., 2011b).Harmonia axyridis has four major colour forms, three of which are melanic, f. conspicua, f. spectabilis, and f.