The threatened Pookila (Pseudomys novaehollandiae) hosts a diverse macrobiome of arthropods at varying risks of co-extinction

The Pookila (Pseudomys novaehollandiae) is a threatened Australian mammal emblematic of the global decline of many vertebrate taxa. While conservationists are concerned with the survival of threatened vertebrates, few consider the rich diversity of symbiotic arthropods which often depend on these hosts for survival. Using P. novaehollandiae as a case study, we demonstrate that even opportunistic sampling can rapidly expand knowledge of the species richness of arthropod symbiont communities on poorly studied vertebrate hosts. We also demonstrate how DNA barcoding can be integrated to provide rapid and inexpensive identification capabilities for non-specialists. Finally, we show how various metrics and methods can be used to quantify and qualify extinction risk of poorly known arthropod symbionts to provide the foundations for conservation action. Implications for insect conservation: This study highlights how opportunistic sampling coupled with DNA barcoding and extinction risk metrics can be used to rapidly and inexpensively characterise the arthropod macrobiomes of rare vertebrates and evaluate the risk of decline of their component taxa.