Tissue-resident microbiomes shape stress resilience and dispersal behavior in an agrobiont spider

Spiders serve as key biological control agents in agroecosystems, but they face repeated disturbances due to common agricultural practices. The wolf spider Pardosa agrestis, a dominant agrobiont species, recolonizes these disrupted habitats via dispersal strategies such as ballooning, particularly during juvenile stages. This study investigated how nutrition and insecticide exposure influence ballooning behavior and the structure-function dynamics of the spider's tissue-resident microbiome. We found that dispersal behavior in P. agrestis is structured and repeatable, driven by environmental cues such as light and wind, and further modulated by previous exposure. Although diet significantly impacted growth and development, it had a minimal influence on the dispersal strategy. The tissue-resident microbiome analysis revealed a diverse, core symbiotic community with notable responsiveness to both dietary and pesticide-induced stress. Specific tissue-resident microbial taxa shifted their predicted metabolic output under nutrient deprivation, suggesting adaptive biosynthetic activity. Importantly, distinct predicted microbial metabolic profiles were associated with spider behaviors (e.g., ballooning) and physiological traits (e.g., endurance), indicating a microbiome-mediated influence on the dispersal capacity. Moreover, tissue-resident microbial community function was correlated with host survival after insecticide exposure, implicating its role in detoxification and resistance. These findings highlight the role of the tissue-resident microbiome as a functional partner in arthropod stress resilience and dispersal behavior in agroecosystems.