Honeybees affect floral microbiome composition in a central food source for wild pollinators in boreal ecosystems

Abstract

Basic knowledge on dispersal of microbes in pollinator networks is essential for plant, insect, and microbial ecology. Thorough understanding of the ecological consequences of honeybee farming on these complex plant–pollinator–microbe interactions is a prerequisite for sustainable honeybee keeping. Most research on plant–pollinator–microbe interactions have focused on temperate agricultural systems. Therefore, information on a wild plant that is a seasonal bottleneck for pollinators in cold climate such as Salix phylicifolia is of specific importance. We investigated how floral visitation by insects influences the community structure of bacteria and fungi in Salix phylicifolia inflorescences under natural conditions. Insect visitors were experimentally excluded with net bags. We analyzed the microbiome and measured pollen removal in open and bagged inflorescences in sites where honeybees were foraging and in sites without honeybees. Site and plant individual explained most of the variation in floral microbial communities. Insect visitation and honeybees had a smaller but significant effect on the community composition of microbes. Honeybees had a specific effect on the inflorescence microbiome and, e.g., increased the relative abundance of operational taxonomic units (OTUs) from the bacterial order Lactobacillales. Site had a significant effect on the amount of pollen removed from inflorescences but this was not due to honeybees. Insect visitors increased bacterial and especially fungal OTU richness in the inflorescences. Pollinator visits explained 38% variation in fungal richness, but only 10% in bacterial richness. Our work shows that honeybee farming affects the floral microbiome in a wild plant in rural boreal ecosystems.

Cross pollination and inflorescence branching in the presence of Mycoacterium canetti in Floral microbiome of Syzygium aromaticum (L) Merr. and Perry

“…There are several ways microbial volatile organic compounds (MVOCs) are bene cial to plants 23 . It is showed that honeybees affect oral microbiome composition 24 . P. uorescens, P. putida, Corynebacterium sp., Fusarium solani, Byssochlamysfulva, and Penicillium simplicissimum, can degrade eugenol, an antibacterial agent present in clove 33 .…”

A quantitative survey of the blueberry (Vacciniumspp.) nectar microbiome: variation between cultivars, locations, and farm management approaches

“…The blueberry nectar microbiome was highly correlated with location. The importance of site-specific factors like the local climate, land cover, flora, and fauna are known to impact microbial community assembly in flowers (Samuni-Blank et al 2014;Aizenberg-Gershtein, Izhaki, Halpern 2017;Vannette et al 2017;Schaeffer et al 2021;Hietaranta, Juottonen, Kytöviita 2023;Schaeffer et al 2023). Floral visitors are particularly significant to the establishment of nectar microbial communities.…”

A diverse and distinct microbiome inside living trees

“…As trees speciated, divergence of inherited microbiomes along phylogenetic lines might be expected. This possibility of microbial inheritance raises further lines of inquiry about species level similarity in different stages of forest succession, and may even beg questions about the potential role of pollinators—a known plant microbiome vector 80 —in shaping tree and wood microbiomes.…”