<p><i>Camponotus japonicus</i> is a widely distributed ant species in East and Southeast Asia and is an important natural enemy of agricultural and forestry pests. As a well-developed queen-right social insect species, a mature <i>C</i>. <i>japonicus</i> colony consists of thousands of individuals, including queens, gynes, males, and various forms of workers, each displaying different morphologies, physiologies, and behaviors related to their division of reproductive roles. Exocrine glands, as a vital part of social communication and organization, also reflect the functional specialization in each caste. In this study, we examined the function of one of the most important but less studied cephalic glands, the prepharyngeal gland (prePG), using transcriptome and metabolome data from four female castes and males of<i> C</i>. <i>japonicus</i>. We observed significant differences in gene expression patterns among various adult forms. As the core members of the colony, queen’s exhibit enhanced immune defense functions, while gynes show stronger digestive capabilities. Minor and major workers, adapted to their more frequent extra-nest activities, secrete greater amounts of volatile components. Furthermore, we infer that the prePG may also play a role in larval fate determination. All these functions are available by releasing its secretions into the trophallactic fluid, thereby spreading across individuals within the colony. Based on the results of this study, future research could focus on regulating caste distribution and larval growth and development within <i>C. japonicus</i> colonies.</p>