Wild gut microbiomes reveal individuals, species, and location as drivers of variation in two critically endangered tropical birds

Abstract

The gut microbiome of an animal has a strong influence on the health, fitness, and behavior of its host, and is thus a critical component of the animal itself. Most research in the microbiome field has focused on human populations and commercially important species. However, researchers are now considering the link between endangered species conservation and the microbiome. In Hawai i, several threats have caused widespread population declines of Hawaiian honeycreepers (subfamily Carduelinae). These threats, and the environmental changes that result, can have a significant effect on the avian gut microbiome and may even lead to disruption of microbial function. However, no previous study has explored the natural patterns of the gut microbiome of a honeycreeper species in the wild. This project used amplicon-based sequencing of the 16S rRNA gene to characterize the gut microbiome of two critically endangered species of Hawaiian honeycreepers. The two species differed significantly in both alpha and beta diversity. Intraspecific variation of the gut microbiome among individual birds was a major factor. However, small but significant differences also exist between sampling location and sexes. This baseline knowledge will help inform management decisions for these honeycreeper species both in their native habitats and in captivity.