AUTHOR=Sela Rotem , Laviad-Shitrit Sivan , Halpern Malka 

TITLE=Changes in Microbiota Composition Along the Metamorphosis Developmental Stages of Chironomus transvaalensis

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.586678

DOI=10.3389/fmicb.2020.586678

ISSN=1664-302X

ABSTRACT=<p>Chironomids (<italic>Diptera</italic>; <italic>Chironomidae</italic>), also known as non-biting midges, are one of the most abundant insects in freshwater habitats. Our aim was to understand whether the metamorphosis developmental stages affect the endogenous microbiota composition of <italic>Chironomus transvaalensis</italic>. Toward our objective, we analyzed the endogenous microbiota composition of <italic>C. transvaalensis</italic>’ four life stages: egg masses, larvae, pupae, and adults. Significant differences were found between the microbiota compositions of the different developmental stages of this <italic>Chironomus</italic> species. We observed a decline in bacterial diversity as the insect evolved from egg mass to adult, while the highest richness was observed in the pupal stage. Although there were significant differences between the microbiota compositions of each life stage, a bacterial core, which included 27 Amplicon Sequence Variants (ASVs), was found in all the developmental life stages (in ≥75% of samples). Chironomids are natural reservoirs of <italic>Vibrio cholerae</italic> and <italic>Aeromonas</italic> species, and the <italic>Vibrio</italic> and <italic>Aeromonas</italic> ASVs were part of the core bacteria. The presence of the <italic>ompW</italic> gene, which is specific to <italic>V. cholerae</italic>, confirmed the presence of this species in all the chironomid’s life stages. Thus, the results provide important insights about the host–microbe interactions in chironomids with a specific understanding of chironomids-<italic>Vibrio-Aeromonas</italic>-microbiota interactions.</p>