Chemical communication often involves complex signals of both insect and plant origin. Much attention has been focused on the behavioral activities of these various components, but less on their sources of variation. Variation in semiochemical signals has implications to pest management and evolutionary theory. Within populations, variations in chemical signaling may arise at several scales, such as host species, individual hosts within species, and individual insects. The pine engraver Ips pini (Say) is distributed transcontinentally, and stereoisomeric ratios of its principal pheromone component ipsdienol vary regionally. We placed male pine engravers on jack, Pinus banksiana Lamb, red, P. resinosa Aiton, and white, P. strobus L. pines and analyzed volatiles from the insects’ frass. Variation in the monoterpene and pheromone volatile profiles was examined at the levels of tree species, individual trees, and individual beetles , with each level partitioned within the next higher level. The ratio of monoterpenes to pheromones in the volatile plumes varied among the three host species, white (1:2), jack, and red pine (1:1). Beetle to beetle variation in plume composition was more than ten times greater than tree to tree variation within a species. Within the pheromone component of the plume, the stereoisomeric ratio of ipsdienol was highly consistent. Inter-beetle variation, however, could be up to 500 times greater than inter-tree variation. These findings provide implications of signal variation to the behavioral ecology of bark beetles.