Data from: Longitudinal gut microbiome dynamics in relation to age and senescence in a wild animal population

In humans, gut microbiome (GM) differences are often correlated with, and
sometimes causally implicated in, ageing. However, it is unclear how these
findings translate in wild animal populations. Studies that investigate
how GM dynamics change within individuals, and with declines in
physiological condition, are needed to fully understand links between
chronological age, senescence, and the GM, but have rarely been done.
Here, we use longitudinal data collected from a closed population of
Seychelles warblers (Acrocephalus sechellensis) to investigate how
bacterial GM alpha diversity, composition, and stability are associated
with host senescence. We hypothesised that GM diversity and composition
will differ, and become more variable, in older adults, particularly in
the terminal year prior to death, as the GM becomes increasingly
dysregulated due to senescence. However, GM alpha diversity and
composition remained largely invariable with respect to adult age and did
not differ in an individual’s terminal year. Furthermore, there was no
evidence that the GM became more heterogenous in senescent age groups
(individuals older than 6 years), or in the terminal year. Instead,
environmental variables such as season, territory quality, and time of
day, were the strongest predictors of GM variation in adult Seychelles
warblers. These results contrast with studies on humans, captive animal
populations, and some (but not all) studies on non-human primates,
suggesting that GM deterioration may not be a universal hallmark of
senescence in wild animal species. Further work is needed to disentangle
the factors driving variation in GM-senescence relationships across
different host taxa.