Molecular phylogeny of New Zealand ladybirds

Evolutionary relationships between native and introduced species has been argued to influence the successful establishment and dispersal of introduced species in novel environments. However, currently there is little data to test this hypothesis in arthropods. Ladybirds provide an excellent opportunity for testing whether evolutionary relationships influence establishment as they are introduced for the biocontrol of agricultural pests and some species are known invasives.

Because we have little understanding of the phylogenetic relationships of New Zealand ladybirds, for my PhD, I constructed the first molecular phylogeny of New Zealand ladybirds (both native and introduced), based on mitochondrial (cytochrome oxidase subunit I gene) and nuclear (28S rRNA) gene data. I used 15 specimens of known origin (native/introduced) to assess the phylogenetic relationship between invasive (n=1), introduced (n=9) and native (n=5) ladybird species. I further included 15 ladybird species of which the origin is unknown.

My data strongly support the monophyly of Coccinellidae and the subfamilies Microweiseinae and Coccinellinae. Further, my data support the monophyly of the tribe Epilachnini and the paraphyly of tribes Coccinellini, Scymnini, Chilocorini and Coccidulini. My data indicate that ecological factors rather than relatedness between introduced and native species influences the establishment of introduced ladybirds in New Zealand.