Gut microbiota of Brazilian Melipona stingless bees: dominant members and their localization in different gut regions

The gut microbiome of eusocial corbiculate bees, which include honeybees, bumblebees, and stingless bees, consists of anciently associated, host-specific bacteria that are vital for bee health. Two symbionts, Snodgrassella and Gilliamella , are ubiquitous in honeybees and bumblebees. However, their presence varies in the stingless bee clade (Meliponini), a group with pantropical distribution. They are absent or rare in the diverse genus Melipona , indicating a shift in microbiota composition in this lineage. To identify the main members of the Melipona microbiota, we combined newly collected and published data from field-collected individuals of several species. Additionally, we identified the localization of the dominant microbiota members within the gut regions of Melipona quadrifasciata anthidioides . The dominant microbiota of Melipona species includes members of the genera Bifidobacterium, Lactobacillus, Apilactobacillus, Floricoccus , and Bombella . Among these, Apilactobacillus and Bombella dominate in the crop, whereas Apilactobacillus and other members of the Lactobacillaceae dominate the ventriculus. The ileum lacks Snodgrassella or Gilliamella but contains a putative new symbiont close to Floricoccus , as well as strains of Bifidobacterium , Lactobacillaceae (including Apilactobacillus ), and Bombella . The rectum is dominated by Bifidobacterium and Lactobacillus . In summary, the Melipona microbiota is compositionally distinct but shows spatial organization paralleling that of other eusocial corbiculate bees.