Gut microbiomes of mammal species show differential responses to
identical series of environmental stressors
Abstract
The gut microbiomes that associate with animals can represent labile
units of cooperating and competing microbes. This lability, sometimes
referred to as metagenomic plasticity, has been posited to have an
important role as an additional axis of hosts’ phenotypic plasticity.
However, whether and how metagenomic plasticity varies across hosts with
different ecological and evolutionary features remains unclear. To
address this, we utilised faecal-derived genome-resolved metagenomics
and compared how the taxonomic, phylogenetic and functional microbial
dynamics varied across a series of disturbances in two mammal species;
namely, the insectivorous-specialist, Crocidura russula (N = 29) and the
omnivorous-generalist Apodemus sylvaticus (N = 22). Although faecal
microbial diversity of both species remained stable, compositional
dynamics differed significantly. C. russula exhibited substantially
higher variability and directionality of microbial responses, with
higher predictability associated with each disturbance, compared to A.
sylvaticus. Predictions of functional traits using joint-species
distribution modelling supported these observations. C. russula showed
strong functional response to perturbations, with marked directional
variation of various metabolic functions. In contrast, the significantly
higher functional diversity and redundancy of the A. sylvaticus
microbiome likely buffered its functional response to perturbations,
which remained more constant across time. Our results indicate that the
intrinsic properties (e.g., diversity, redundancy) of gut microbiomes
associated with animals with different biological attributes shape the
taxonomic, phylogenetic, and functional response to environmental
stressors. This level of plasticity might affect the capacity of animal
hosts to acclimate and adapt to changing environments.