Variation in the microbiome in response to parasite, bat host, and
environment
Ordination and PERMANOVA of microbiome communities provide evidence that
aspects of the parasite (i.e., parasite family and species), the host
bat (i.e., bat family, bat sex, and bat individual), and landscape
factors (i.e., region and sampling site) significantly contributed to
bat fly microbiome variation (Table 2; Figure 3 and Figure S5). Other
variables significantly contributed to microbiome community
differentiation (i.e., bat feeding guild, bat species, protection status
of sampling site, habitat fragment area, and isolation), but violated
the assumption of homoscedasticity. Parasite species, parasite family,
bat feeding guild, bat family, bat species, and sampling site had the
largest effect sizes, however many of these variables are correlated
with each other.
We used sequential sum of squares with free permutation to account for
the hierarchical structure of the study system, and found that parasite
species significantly impacted microbiome community structure (Table 3).
Habitat fragment area, distance to source, and protection status also
significantly contributed to microbiome variation, but violated the
assumption of homoscedasticity. As the order of variables in sequential
sum of squares can impact their significance when sample sizes are
uneven, we also examined the impact of parasite, host bat, and landscape
variables on the four most well-sampled species (Table S1; Figure 4).
None of the test variables significantly explained microbiome variation
without violating PERMANOVA assumptions.