Phylogenetic Constraints and Ecological Implications of Gut Bacterial Communities in Necrophagous Flies

Abstract

This study examines the gut bacterial communities of four necrophagous fly species: Lucilia illustris, L. caesar, Chrysomya megacephala, and C. pinguis. The gut bacterial communities exhibited significant variation across species, showcasing a diverse range of bacterial phyla, classes, and genera. Each species harbored a unique set of bacteria, yet there was considerable overlap in taxa among species. Species richness was comparable across all species. However, measures that account for both richness and evenness, such as the Shannon diversity index and the inverse Simpson’s diversity index, indicated significant differences between species, especially between L. illustris and C. pinguis. The functional profiles of the gut bacterial communities mainly centered on metabolic and environmental information processing functions, with no marked differences between species. While this study had limitations in data collection, it still revealed a significant correlation between the phylogenetic distances of some fly species and the distances of their gut bacterial communities. This supports the hypothesis that the gut microbiota is not random but is influenced by the host’s evolutionary history or seasons. We confirmed that an association between phylogeny and gut bacterial community structure, as determined through entanglement analysis, exists. The study focused on only five individuals from the four fly species sampled during spring and summer, which might affect the generalizability of the results. Future research would benefit from replicating this study with a larger sample size across various seasons to ensure the more widespread applicability of the findings.