Lactobacillus apisdorsatae sp. nov. from the giant honeybee (Apis dorsata), Lactobacillus pollinatoris sp. nov. and Lactobacillus xylocopae sp. nov., from the carpenter bee (Xylocopa violacea)

Insects host diverse and distinctive communities of gut mutualistic bacteria, including lactic acid bacteria of the Lactobacillus genus. Recently, most research in the insect microbial taxonomy has focused on identifying novel Lactobacillaceae species in managed insects such as Apis mellifera and few species of Bombus spp. from North America, Europe, and China. However, the gut microbiota of wild insects remains largely unexplored. Yet, insects represent the largest animal class and a vast, untouched source of novel microbial symbionts, especially in wild populations. This study focuses on the isolation and characterization of novel Lactobacillaceae strains from wild and solitary insects, such as the carpenter bee (Xylocopa violacea), the strawberry seed beetle (Harpalus rufipes), and the giant honeybee (Apis dorsata). Full-genome sequencing and annotation, including investigation of distinctive functional traits, were performed for these strains, along with phenotypic characterization of sugar fermentation, enzymatic activity, cellular fatty acid profiles and G + C content. Phylogenetic relationships were determined using 16S rRNA gene sequences and core genome computation, which confirmed the classification of novel taxa within the Lactobacillus genus. From the aforementioned insect species, three novel Lactobacillus species were isolated and characterized: Lactobacillus xylocopae XV31L (= DSM 120036T = MSCL 1776T) and Lactobacillus pollinatoris XV13L (= DSM 104957 T = LMG 30141T) from X. violacea, and CA30L (= DSM 119968R = MSCL 1777R) from H. rufipes, and Lactobacillus apisdorsatae C449L (= VTT E-263657 T = MSCL 1775T = NCCB 101125T) from A. dorsata.