The role of microbial symbionts in host stress tolerance remains underexplored. Gut microbiome studies in Drosophila melanogaster have largely focused on bacteria, whereas yeasts have been assumed to provide nutrition rather than engage in true symbiosis. We explored the effect of gut yeasts on chill coma recovery time (CCRT, a proxy for cold tolerance) and its yeast species-specificity and dependence on live yeast cells. We generated flies with distinct gut microbiota conditions: axenic (microb