The Fecal Microbiota of Cornu aspersum

The herbivorous common brown garden snail, Cornu aspersum, represents an understudied animal host, despite its widespread geographic distribution and applications. In this study, we used 16S rRNA gene amplicon sequencing population analysis to describe changes in the fecal microbiota of wild-caught snails that were lab reared and fed a non-sterile plant diet over 21 days. At the outset of the experiment, wild-caught snails harbored diverse populations of Gammaproteobacteria. Two of the most abundant genera were soil-associated Pseudomonas and Buttiauxella, an understudied genus often reported in snails and slugs. During penicillin treatment, Gammaproteobacteria diversity in experimental snails bottlenecked, resulting in Pseudomonas takeover. Following penicillin treatment, experimental snails began to recover, with fecal samples containing pre-treatment Gammaproteobacteria groups by day 21. Because the food source was not sterile, it provided its own population of Gammaproteobacteria, primarily Pseudomonas, which seeded snails daily. Given that Buttiauxella was not observed on the food source, we hypothesize that it was present and maintained within the digestive tract; supporting the idea that C. aspersum maintains an endogenous gut microbiome.