Does genetic variation among invasive house mice in New Zealand affect eradication success?
House mice (Mus musculus) were introduced to New Zealand accidentally in 1824 following the stranding of an Australian ship. Phylogeographic analyses have revealed many subsequent introductions from diverse sources. Mice have significant negative impacts on native ecosystems in New Zealand and elsewhere. This makes their eradication a desirable conservation outcome, yet a large proportion of mouse eradication attempts worldwide have failed for unknown reasons. We used a phylogeographic approach to identify mitochondrial DNA (mtDNA) D-loop haplotypes of mice obtained from 12 previously unsampled island and mainland sites to expand the previous sampling range for investigation of mouse genetics in New Zealand, and to test the hypothesis that eradication failure is linked to either mouse subspecies or source population as indicated by D-loop haplotype. We predicted that populations that had survived an eradication attempt would be of a different mouse subspecies or D-loop haplotype from those where eradication had succeeded. In addition, mouse populations at failed eradication sites may have a common D-loop haplotype, indicating a shared source population that may be more resistant to eradication attempts. Twenty-five complete mtDNA D-loop sequences were generated, describing six haplotypes including two D-loop haplotypes that had not previously been recorded in New Zealand linking New Zealand mice to populations in Portugal and Iran. A Portuguese haplotype was also recorded for the two geographic outgroup specimens sourced from Reunion Island, Indian Ocean; the first recorded mouse D-loop haplotype from that location. Mice sampled from six New Zealand populations where eradication outcome was known all possessed domesticus D-loop haplotypes. Mice in four of these six populations (three successful eradications and one failure) possessed the same D-loop haplotype (domNZ.04) making it difficult to infer a link between D-loop haplotype and mouse eradication success. Further sampling in New Zealand may uncover additional haplotypes linking New Zealand mice to other areas.