Decades of research have been dedicated to understanding how host traits predict the transmission dynamics of infectious agents. Despite empirical, anecdotal, and axiomatic evidence that individuals vary in phenotypes that could influence microbial transmission, individuals are often considered identical in predictive models or experimental designs. Here, we test to what degree variation in host phenotypes can alter the direct and indirect transmission of bacteria to a susceptible, unexposed colony-mate. We inoculated individual social spiders, Stegodyphus dumicola, with GFP-transformed Pantoea sp., a resident cuticular bacterium, and allowed them to directly interact with a colony-mate for 24h. Using selective growth media and surveying for GFP fluorescence from bacteria cultured from unexposed individuals’ cuticles, we found evidence for transmission in 58% of cases, the likelihood of which was influenced by the phenotypes of both the exposed and susceptible individuals. Transmission was more likely when exposed spiders exhibited higher “boldness”, a key behavioral trait for this species, and when unexposed individuals were in better body condition (i.e., weighed more than predicted based on their body size). When unexposed spiders were housed for comparable periods of time solely with silk with which exposed spiders had previously interacted, indirect transmission took place in only 11% of cases. Thus, bodily contact or other affiliative/social behaviors appear to play an important role in higher incidence of bacterial transmission among co-resident spiders. These data represent a fundamental step towards understanding how individual traits can influence larger scale epidemiological processes.