Abstract/Summary

Twenty-three species belong to the Palaearctic Anthrenus pimpinellae complex. All Anthrenus spp. have intricate dorsal colour patterns. They can do this courtesy of the many small, coloured scales that coat their bodies, rather like Lepidoptera. All species within the complex are generally black/orange with an obvious trans-elytral wide band. One species, A. isabellinus, differs from most other species from the complex in that it displays a wide range of colour patterns, from the typical dark with white elytral fascia to almost pure white individuals. In the current study, we demonstrate that a continuous range of colour patterns exists within a population of A. isabellinus from Greece, negating the necessity to name variants as subspecies to account for the pattern variation. It is more likely that the pattern variation is an example of phenotypic plasticity. There is no evidence for sexual dimorphism in colour pattern variation. The range in colour pattern adopts a ‘broken stick’ pattern, which is discussed in relation to variation in numbers of individuals falling into different pattern categories, and the possibility that the broken stick appearance of the pattern range is an example of canalization. The white fascia across a dark background is consistent with a pattern that has evolved to disrupt the outline of the beetle (anti-predator). Most A. isabellinus, indeed most species within the A. pimpinellae complex, display this colour pattern so it is possible that canalization occurs to produce this colour pattern.