The acoustic ecology of bark beetles

Many animal species have evolved multiple modes of communication. These signals convey different types of information intended for potential mates, competitors and/or predators and are also subject to exploitation. Bark beetles are well-suited for studies of communication as they use both chemical and acoustic signals. Bark beetles respond to chemical cues in frass with acoustic signals and subsequently release anti-aggregation pheromones when exposed to acoustic calls. Though much research has focused on chemical communication, our understanding of acoustic communication has not advanced adequately to begin addressing the relative influence of chemical and acoustic signals in bark beetles. The importance of acoustic communication during host tree selection and sequentially throughout reproduction is poorly understood. Moreover, it is unknown if predators respond to and exploit acoustic signals in ways similar to their response to bark beetle pheromones. We investigated the importance of acoustic signals of Ips pini during interactions among conspecifics, heterospecifics and predators. We conducted playback experiments in the laboratory and field to determine the influence of acoustic signals on bark beetle predators and host tree selection. In field playback trials, acoustic signals of Ips pini were played at funnel traps with and without chemical lures. In laboratory experiments we assessed the effect of bark beetle acoustic signals on bark beetle predators. The impact of acoustic signals on inter- and intraspecific interactions among bark beetles and their predators and implications for bark beetle ecology and management will be discussed.