Data for: Intraspecific variation in dispersal probability and host quality shape nectar microbiomes

Filtering of epiphytic microbes can occur through plant traits and
deterministic dispersal-mediated processes. This filtering can affect
microbiome assembly yet their relative contribution to predictable
variation in microbiome is poorly understood. We collected this data set
to test the impact of host-plant filtering and dispersal on nectar
microbiome presence, abundance, and composition. We inoculated bacteria
and yeast into 30 plants across 4 phenotypically distinct cultivars of
Epilobium canum. We compared the growth of inoculated communities to
openly visited flowers from a subset of the same plants.  We
found evidence of host-selection when we inoculated flowers with synthetic
communities. However, the host-plants with the highest microbial densities
when inoculated did not have the highest microbial densities when openly
visited. Host plants predictably varied in the presence or absence of
bacteria, which was correlated with pollen receipt, suggesting a role for
deterministic dispersal.  These findings suggest that host
filtering could drive plant microbiome assembly in tissues where species
pools are large and dispersal is high.  However deterministic
differences in microbial dispersal to hosts may be equally or more
important when microbes rely on an animal vector, dispersal is low, or
arrival order is important.