Bark beetles (Coleoptera: Curculionidae) are among the important pests of forest in the world and in Turkey. Pine-feeding bark beetles interact chemically with their host tree via the behavioral, physiological, and biochemical effects of one class of monoterpenes. The half of oleoresin producing by trees such as pines, spruces, firs in the forests is the monoterpene. The monoterpenes occur in the oleoresin and function as behaviorally active kairomones for pine bark beetles and their predators, presenting a classic example of tritrophic chemical communication. The monoterpenes are aggregation pheromones for pine bark beetle. In the control of bark beetles, monoterpenes are used in traps. For example, the monoterpenes are an attractant for bark beetles. Also, Myrcene is used for a synergistic effect in the trap. Monoterpenes can toxic to insects. Limonene is among the most toxic monoterpenes to bark beetles. Also, the interaction is found between monoterpenes and prey of bark beetle. Monoterpenes are enhanced to respond of predatory to the pheromone of bark beetle.