Non-invasive recovery of brushtail possum (Trichosurus vulpecula) DNA from bait interference devices

In New Zealand the Brushtail Possum is managed as a significant pest of conservation and primary production concern. In situ DNA recovery from this species has many potential management and research applications, such as determination of species presence, identification of individuals, mark-recapture studies, or monitoring re-invasion in low-density populations. A novel non-invasive DNA sampling tool, the Wax Tag®, a bait interference device, was presented to captive and wild possums. DNA was recovered from bitten tags using the Qiagen DNeasy, tissue and blood extraction protocols. Using Polymerase Chain Reaction amplification of a 407bp fragment of the Cytochrome Oxidase 1 region, we were able to achieve 94% DNA recovery from captive possums, and 68% recovery from wild possums. We also had strong indication that these recovery rates could be significantly improved through minor changes to the amplification recipe. Sequencing from 23 captive possums confirmed the species with a 99% match on GenBank. Mouse DNA was also recovered from bitten tags and the species was genetically confirmed with a 96% match on Gen bank. In this study we established that bait interference devices can be used to non-invasively sample possum DNA in the field, and that WaxTags® are a useful tool for collecting this DNA, both for possums and for other species. This method could have applicability for management of other species, such as endangered marsupials in Australia