Coconut Rhinoceros Beetle mitochondrial genomes assessment refines understanding of its Pacific invasions

We used draft mitochondrial genomes (mitogenomes) to explore introduction histories of the destructive coconut rhinoceros beetle (CRB, Oryctes rhinoceros L.) throughout the Pacific and its native range, focusing on re-evaluating the relationship between members of the CRB-G haplotype grouping ( sensu Marshall et al. 2017) as previously assessed by the partial mtCOI (mitochondrial DNA cytochrome oxidase subunit I ) gene. Mitogenome analyses that included historical CRB collections confirmed the 2007 invasive CRB population in Guam was found only in Guam, while there was a detection of a second novel CRB mitogenome, suggesting a new recent introduction(s) into Guam. Further, mitogenome analyses linked: Palau CRB with Indonesia and Philippines native range populations; Papua New Guinea and Solomon Islands CRB with native range Malaysia CRB; Marshall Islands CRB with Solomon Islands CRB; and Samoa and Fiji CRB with Sri Lanka. We therefore provided evidence of historical and current CRB hitchhiking pathways between various native and introduced locations. The results build upon the previous partial mtCOI marker framework to improve the resolution of diversity present within CRB. This study also highlights a need to implement new CRB population nomenclatures based on full mitochondrial DNA genomes.