Parasite species identity and local community diversity mediate effects
of habitat fragmentation on bacterial microbiomes.
Abstract
Arthropod ectoparasites generally have nutrient-poor diets and are
dependent on their bacterial symbionts for nutrient acquisition,
development, and immune response initiation. As the body of research on
parasite-microbiome interactions continues to grow, it is becoming more
apparent that the parasite is not an island that physically and
biologically constrains the microbiome. Suitable habitat fragment size,
isolation, and distance from a source are important variables
influencing community composition of plants and animals, but the role of
the environment in determining composition and variation of
host-associated microbial communities is poorly known. It is
hypothesized that evolution and ecology of an arthropod parasite will
influence its microbiome more than broader environmental factors, but
this hypothesis has not yet been tested. To compare the relative
influence of the broader environment to that of phylogenetic constraint
on the microbiome, we applied high-throughput sequencing of the V4
region of 16S rRNA from 222 obligate ectoparasitic bat flies (Streblidae
and Nycteribiidae) collected from 155 bats (representing six species)
from ten habitat fragments in the Atlantic Forest of Brazil. We find
that parasite species identity is the strongest driver of microbiome
composition. To a lesser extent, reduction in habitat fragment area is
associated with a reduction in connectance of microbial interaction
networks and an increase in modularity, but size-independent measures of
network topology and bacterial taxon richness do not show an impact of
the environment. Instead, habitat fragments that support more diverse
bat and bat fly communities also support more connected bacterial
interaction networks.