Bacterial and fungal community composition in the regurgitant of four Spodoptera species

While insect gut microbiomes have been extensively studied, the extent to which closely related herbivores share a core microbiome remains largely unexplored. In this study, we investigate the bacterial and fungal communities in the regurgitant of four highly polyphagous Spodoptera species (S. exigua, S. frugiperda, S. latifascia, S. littoralis) fed four different diets (artificial diet, cotton, maize, squash). Our findings reveal that diet drives species-specific changes in bacterial communities, suggesting selective microbial recruitment by the host. However, we found no evidence of a conserved core microbiome across Spodoptera species, challenging the assumption that related herbivores maintain shared microbial symbionts. By providing a comparative analysis of microbiome compositions across multiple species and diets, our study offers novel insights into the microbial dynamics of generalist insect herbivores. Understanding how gut microbial communities vary among closely related polyphagous pests may help explain their ability to exploit diverse host plants, with potential applications for microbiome-based pest management strategies.