Commensal bacteria residing in the digestive tracts affect the host lifespan, and their composition is influenced by environmental factors such as diet and pharmacological intervention. While there is evidence from many studies to suggest that maintaining a healthy/balanced gut microbiome is important delaying the aging process, the relationship between the gut microbiome and aging is not yet clearly understood. This study focused on the relationship between commensal microbiota and host longevity by dietary supplementation in Drosophila melanogaster, a well-established model organism for aging and host-microbe studies. Specifically, this study demonstrates the role of commensal microbes in the longevity effects of dietary restriction (DR), which is the most well-known intervention for retarding aging and extending the lifespan in diverse organisms. Further, it explores how commensal microbiota affects host intestinal homeostasis and stem cell differentiation under DR. In addition to DR, various dietary supplements reported to extend lifespan have shown a relationship between their longevity effects and commensal microbes. Aronia berry, well known for its richness in polyphenolic compounds with various physiological and pharmacological activities, has been shown to extend lifespan in fruit flies and modulates human gut microbiota. However, the relationship between microbes and Aronia berry has yet to be well elucidated. Therefore, this study investigated the influence of commensal microbes on the longevity effect of Aronia berry, revealing the impact of host-microbe interaction on the longevity effect of Aronia berry. Here, this study, which elucidates the relationship between commensal microbes and the longevity effect of dietary interventions, will provide fundamental knowledge for understanding the underlying mechanisms of host aging and the regulation of lifespan through dietary interventions.