Diversidade, sucessão e identificação de fungos cultiváveis ao longo do processamento do pólen, no desenvolvimento embrionário e no trato digestivo de Melipona interrupta Latreille, 1811 e Melipona seminigra Friese, 1903

Abstract

The present research aimed to investigate the association of fungi with the pollen route, cerumen and honey in the hives of two species of stingless bees of the genus Melipona — Melipona interrupta and Melipona seminigra — with a focus on characterizing the fungal microbiota present in different substrates related to larval development and caste biology. The central hypothesis considered the potential for a mutualistic relationship between fungi and bees, in which fungi play a relevant role in larval nutrition and possibly influence embryonic development. To this end, fungal microbiota were isolated from eight distinct substrates within the hives, including stored pollen (samburá), larval food at the egg, larval, and pupal stages, as well as the gut of newly emerged workers and queens, honey, and cerumen. Fungal identification involved macro- and micromorphological analyses, along with sequencing of the ITS1-5.8S-ITS2 rDNA region. Fungal diversity was assessed based on the frequency and richness of colony-forming units (CFUs). In total, 9,034 CFUs were isolated, with 6,535 from M. interrupta and 2,686 from M. seminigra. Thirty-six distinct fungal taxa were identified (28 filamentous and 8 yeast-like), in addition to unidentified morphotypes of basidiomycetes, filamentous fungi, and yeasts. The most prevalent yeast genera were Starmerella, Debaryomyces, and Zygosaccharomyces, while among filamentous fungi, the most relevant genera were Aspergillus, Cladosporium, Penicillium, and Monascus. The gut was the substrate with the greatest fungal diversity and abundance in both species, particularly in worker pupae. The analysis revealed a clear fungal succession along the pollen pathway, with variations in fungal types and quantities across substrates. Starmerella was the dominant genus in both bee species, underscoring the potential role of pollen as a vector for fungi into the hive.