Solitary bees are valuable contributors to overall pollination of natural and cultivated plants, therefore it is of high interest to study their survivability rates and fitness, as well as their effectiveness in recruiting offspring. Temperature shifts and landscape degradation have been set in the centre of bee health research; there is though still a high level of larval mortality that remains unexplained. Observations such as the higher larval mortality rates in connected populations suggest that symbiotic or opportunistic microbes may be a key factor in such a study. Although the microbiomes of honey bees and other eusocial relative species have been set under investigation in various studies, microbial assessments of solitary bees, not rejoicing in the benefits of a hive system, are currently lacking.
We focus on solitary bees microbiome investigation not only for the identification of pathogens, but also for the identification of other bee-microbe associations such as those of mutualistic partners. We address the question of whether these associations are evolutionary conserved, regardless of the solitary life style which deprives the different species of a closed nurturing system of the larvae and we investigate the possible microbial transmission routes. A culture independent next-generation sequencing investigation of solitary bee nests has been established to identify and characterize microbial associates in terms of origin and function. These are related to ecological factors bearing in mind the different life styles of different solitary bee species. In the direction of characterizing different taxa as commensal or mutualistic in terms of nutrition and pathogen defense, we design functional bioassays to check culture-isolated bacterial strains for possible fermentative and antimicrobial abilities. Genome investigation of isolated microbial strains is also important to delineate the role of them in the overall community.