The wild solitary bees Andrena vaga, Anthophora plumipes, Colletes cunicularius, and Osmia cornuta microbiota are host specific and dominated by endosymbionts and environmental microorganisms

Abstract

We characterized the microbial communities of the crop, midgut, hindgut, and ovaries of the wild solitary bees Andrena vaga, Anthophora plumipes, Colletes cunicularius, and Osmia cornuta through 16S rRNA gene and ITS2 amplicon sequencing and a large-scale isolation campaign. The bacterial communities of these bees were dominated by endosymbionts of the genera Wolbachia and Spiroplasma. Bacterial and yeast genera representing the remaining predominant taxa were linked to an environmental origin. While only a single sampling site was examined for Andrena vaga, Anthophora plumipes, and Colletes cunicularius, and two sampling sites for Osmia cornuta, the microbiota appeared to be host specific: bacterial, but not fungal, communities generally differed between the analyzed bee species, gut compartments and ovaries. This may suggest a selective process determined by floral and host traits. Many of the gut symbionts identified in the present study are characterized by metabolic versatility. Whether they exert similar functionalities within the bee gut and thus functional redundancy remains to be elucidated.

Eupransor demetentiae gen. nov., sp. nov., a novel fructophilic lactic acid bacterium from bumble bees

“…Additional isolation experiments using MRS supplemented with fructose may reveal more information on the prevalence of this organism in bumble bees. Large-scale isolation campaigns of gut samples of Asian hornets ( Vespa velutina ) and the solitary bees Andrena vaga , Anthophora plumipes , Colletes cunicularius and Osmia cornuta [13, 43] involved the use of MRS supplemented with 2 % fructose but did not yield isolates similar to strain LMG 33000 T . A Protologger analysis indicated that the same taxon was present in other insect microbiome datasets at minor relative abundances suggesting it is not a numerically abundant organism when present.…”

Microbial Metamorphosis: Symbiotic bacteria and fungi proliferate during diapause and may enhance overwintering survival in a solitary bee

“…Actinobacteria are frequently isolated from soil and plants, but not often from flowers, with the exception of this study and a study on Pulmonaria nectar, in which 50% of the OTUs recovered belonged to Actinobacteria (71). Investigations of Pulmonaria pollination showed that Anthophora plumipes was an important pollinator, and separate microbial characterization of adults revealed persistent associations with Streptomyces (45). Anthophora urbana has also been found to host prevalent fungi, which are present in live brood cells (72).…”

“…Secondly, the microbiome described here is complex and nearly all brood cells are dominated by 6 core bacterial genera and a single fungus. In previous work on solitary bees, brood cell bacterial microbiomes are highly variable among individuals or composed of more limited taxa (18,19,40,(44)(45)(46). Most commonly in brood cells with consistent microbial communities, lactic acid bacteria are dominant in the provisions, but disappear before pupation (18,19).…”

Cladosporium—Insect Relationships

“…were reported as prevalent in the gut of males of the Asian tiger mosquito (Aedes albopictus: Diptera, Culicidae) and are considered to play a role in the assimilation of fructose, which is a relevant component in their nectarivorous diet [86]. As part of an extensive array of microorganisms that play a crucial role in the digestion of feed, in the absorption of nutrients and in the protection against pathogens, the occurrence of Cladosporium in the digestive tract has been documented in many unrelated insect species, both after direct isolation [3,15,19,24,26,47,50,51,58,59,78,79,100,101,118,125,127] and as a result of studies based on biochemical (e.g., denaturing gradient gel electrophoresis) and metagenomic analyses [3,40,47,88,90,101,[107][108][109]117,118,125,133,138,141,144,146,151,154,161,230]. In addition to descriptive aims, these studies have addressed various aspects that more or less influence the gut microbiome species assortment, such as age, instar, gender, caste, diet, pesticides, antibiotics and various environmental factors.…”