Linked networks reveal dual roles of insect dispersal and species sorting for bacterial communities in flowers

Abstract

Due to the difficulty of tracking microbial dispersal, it rarely possible to disentangle the relative importance of dispersal and species sorting for microbial community assembly. Here, we leverage a detailed multilevel network to examine drivers of bacterial community assembly within flowers. We show that plant species with similar visitor communities tend to have similar bacterial communities, and visitor identity to be more important than dispersal rate in structuring floral bacterial communities. However, plants occupied divergent positions in plant-insect and plant-microbe networks, suggesting an important role for species sorting. Taken together, our analyses suggest dispersal is important in determining similarity in microbial communities across plant species, but not as important in determining structural features of the floral bacterial network. A multilevel network approach thus allows us to address features of community assembly that cannot be considered when viewing networks as separate entities.

Susceptibility of Red Mason Bee Larvae to Bacterial Threats Due to Microbiome Exchange with Imported Pollen Provisions

“…Lactobacilli are associated with key roles in pollen fermentation and defense against bacterial pathogens [ 66 ], possibly by secreting antimicrobial substances [ 67 ]. In our case, the lactobacilli found in high abundances for the deceased larvae might have originated from other bees via flowers [ 30 , 32 , 65 , 68 , 69 ]. They might then thrive on the large amounts of available organic pollen resources in the absence of an Osmia bicornis larvae and its microbial associates, which could both compete with and suppress Lactobacillus in the nest [ 52 , 59 , 70 ].…”

Diet Breadth Affects Bacterial Identity but Not Diversity in the Pollen Provisions of Closely Related Polylectic and Oligolectic Bees

“…Conversely, if specialists interact with the same plants as generalists do, both classes of bees may be exposed to the same microbes. The microhabitats of specialist and generalist bee pollen provisions may filter different microbes based on pollen and nectar chemistry, altering microbial composition as has been found with nectar microbial communities [20]. Comparing the pollen-provision microbial communities of closely related specialist and generalist bees will help address how diet breadth affects microbe exposure and establishment.…”

Peer Review #1 of "Horsenettle (Solanum carolinense) fruit bacterial communities are not variable across fine spatial scales (v0.1)"

“…Recent studies found that plant communities with a similar floral visitor community have similar microbes (Rebolleda Gómez & Ashman, 2019;Zemenick et al, 2019). However, they found that while flowers were hubs for arthropod visitation, flowers did not necessarily serve as hubs for microbes, which suggests a degree of host sorting (Zemenick et al, 2021) which supports the idea that floral visitors shape microbial communities. However, little is known regarding how this could impact fruit microbial communities.…”

“…Fruit and flowers are especially warranted to studies at finer spatial scales, as pollinator interactions are most likely to impact these tissues (Rebolleda-Gómez et al, 2019;Ushio et al, 2015;Zemenick et al, 2021). Recent studies found that plant communities with a similar floral visitor community have similar microbes (Rebolleda Gómez & Ashman, 2019;Zemenick et al, 2019).…”