Using DNA barcodes to investigate the taxonomy of the New Zealand sooty beech scale insect

Abstract

It is currently proposed that there are two species of honeydew-producing sooty beech scale insects (Ultracoelostoma spp.) in New Zealand. It is thought that U. brittini lives exclusively on trunks of southern beech (Nothofagus spp.) trees, while U. assimile occurs mainly on branches. This study aimed to confirm this habitat specialisation by using a molecular genetic approach. We sequenced the c. 650 base pair DNA 'barcode' region of the mitochondrial gene cytochrome c oxidase I (COI) from specimens collected from Mount Grey/Maukatere (North Canterbury), Greymouth, and the Nelson Lakes region. Although the COI sequences supported the existence of two species, there was no evidence of the two species specialising on trunk or branch microhabitats. The excess sugar that these insects excrete as honeydew is an important energy source upon which many native birds and insects depend. Further geographic sampling is needed to determine the distribution and extent of sympatry of the two species detected in this study, which might have implications for forest management decisions.