Aim Determine the geographical and temporal origins of New Zealand cicadas.
Location New Zealand, eastern Australia and New Caledonia.
Methods DNA sequences from 14 species of cicadas from New Zealand, Australia, and New Caledonia were examined. A total of 4628 bp were analysed from whole genome extraction of four mitochondrial genes (cytochrome oxidase subunits I and II, and ribosomal 12S and 16S subunits) and one nuclear gene (elongation factor-1 alpha). These DNA sequences were aligned and analysed using standard phylogenetic methods based primarily on the maximum likelihood optimality criterion. Dates of divergences between clades were determined using several molecular clock methods.
Results New Zealand cicadas form two well-defined clades. One clade groups with Australian taxa, the other with New Caledonian taxa. The molecular clock analyses indicate that New Zealand genera diverged from the Australian and New Caledonian genera within the last 11.6 Myr.
Main conclusions New Zealand was likely colonized by two or more invasions. One NZ lineage has its closest relatives in Australia and the other in New Caledonia. These invasions occurred well after New Zealand became isolated from other land masses, therefore cicadas must have crossed large bodies of water to reach New Zealand.