A comparison between allozyme data and phenotypic distances from defensive secretion in <i>Oreina</i> leaf-beetles (Chrysomelinae)

The genetic relationships between five Oreina species (Chrysomelidae, Coleoptera) were studied. Of these species, four (<i>O. bifrons</i>, <i>O. gloriosa</i>, <i>O. speciosa</i>, <i>O. variabilis</i>) feed on Apiaceae and secrete mixtures of autogenous cardenolides from defensive glands, whilst the other (<i>O. speciosissima</i>) feeds on Asteraceae and is able both to produce cardenolides and to sequester pyrrolizidines N-oxides (PAs). A dendrogram based on the different mixtures of cardenolides produced by the different species agreed with these genetic relationships. In other words, cardenolide mixtures are good taxonomic markers, since the clustering method based on chemical defense produces a branching pattern similar to that based on genetic relationships.