Abstract
The kōkako (Callaeas wilsoni) are endemic wattlebirds native to Aotearoa, New Zealand. Kōkako populations are now restricted to the North Island, with the South Island kōkako thought to be extinct. Historically, the North Island kōkako population decline was attributed to the predation of eggs and chicks during the breeding season by bushtail possums and ship rats. Kōkako live in dense forests with a canopy of tawa, and their diet mainly consists of fruit and foliage from the shrubs surrounding them, but occasionally also invertebrates.
Fortunately, small populations of kōkako have been translocated to predator-free environments and have increased in numbers. Protecting the genetic diversity of the remaining kōkako population is crucial to prevent their extinction, with infectious disease a significant threat to their survival. This study will explore, for the first time, the kōkako virome. I will investigate the diversity and abundance of the North Island kōkako virome to determine if they harbour any potential pathogenic viruses and if their location influences their virome composition.
I performed a metatranscriptomic study of eighteen kōkako cloaca swab samples surveyed from three distinct locations in the Northern Pureora Forest Park. Deep RNA sequencing was performed on the samples to reveal the entire virome of the species within each location. From this data, I identified numerous novel viral sequences spanning 36 viral families, eleven of which were determined to have potential vertebrate hosts. Phylogenetic analysis of three of the eleven viral families containing RNA-dependent RNA polymerase (RdRp) sequences revealed four novel kōkako cloacal-associated viruses and two known viruses. Additionally, I observed overall differences in virome composition amongst the kōkako viromes sampled from different locations. Collectively, the results suggest that the kōkako virome is highly diverse and that the vast majority of viruses discovered in the kōkako cloacal samples are most likely to be environmental or dietary-related.
My findings support previous research that wild avian viromes are diverse and add to our knowledge of the kōkako virome, which could aid in its conservation. A larger sample size surveyed over different seasons would provide a more accurate representation of the virome over time and further improve our knowledge of viral communities in wild avian hosts.