02 September 2019
Solitary bees build their nests by modifying the interior of natural cavities, and they provision them with food by importing collected pollen. As a result, the microbiota of the solitary bee nests may be highly dependent on introduced materials. In order to investigate how the collected pollen is associated with the nest microbiota, we used metabarcoding of the ITS2 rDNA and the 16S rDNA to simultaneously characterize the pollen composition and the bacterial communities of 100 solitary bee nest chambers belonging to seven megachilid species. We found a weak correlation between bacterial and pollen alpha diversity and significant associations between the composition of pollen and that of the nest microbiota, contributing to the understanding of the link between foraging and bacteria acquisition for solitary bees. Since solitary bees cannot establish bacterial transmission routes through eusociality, this link could be essential for obtaining bacterial symbionts for this group of valuable pollinators.
This article has earned an Open Data Badge for making publicly available the digitally‐shareable data necessary to reproduce the reported results. The data is available at https://www.ebi.ac.uk/ena/data/view/PRJEB27223, https://www.ebi.ac.uk/ena/data/view/PRJEB31610, and https://doi.org/10.5061/dryad.qk36k8q
We investigated the importance of imported pollen for the solitary bee nest microbiomes, as its inclusion introduces a wide diversity of environmental and primarily floral bacteria. The simultaneous investigation of pollen composition and nest microbiota showed that both bacterial diversity and composition can be influenced by the foraging preferences of each bee species. Also, we were able to suggest associations with specific bacterial taxa as possibly secured through plant visitation. The present study contributes to the understanding of the complex relationships in the plant–pollinator–microbe triangle.