Conclusion
We found that gut microbiome tracks host evolution in multiple
independent translocations in the wild. By studying multiple stages of
this co-evolution, we revealed that the gut microbiome rapidly diverges
from that of source populations – with shifts in gut morphology and
environment changes – and inconsistently converges with LP native
populations. We argue that lack of parallel convergence does not
preclude a role for the microbiome in guppy evolution; in fact,
microbiomes may provide a consistent nutritional advantage to guppies
introduced to low-resource environments, provided there is the
sufficient richness to filter from. In contrast to much of our knowledge
of host-microbiome evolution based on macro-evolutionary patterns, our
study offers an unprecedented view of host-microbiome co-evolution in
real-time in wild populations.