Behavioral responses of three species of ground beetle (Coleoptera: Carabidae) to olfactory cues associated with prey and habitat

The responses of Pterostichus melanarius Illiger, Hat-pains rufipes DeGeer, and Nebria brevicollis Fabricius (Coleoptera: Carabidae) to olfactory cues of prey and habitat were studied in a four-arm continuous-airflow olfactometer. The process was semiautomated using time-lapse image analysis by microcomputer, The primary constituent of the aphid alarm pheromone, (E)-beta-farnesene (EBF), was synthesized and tested for a kairomonal role in prey detection by carabids. In addition, individual beetles were exposed to odors from live aphids, live collembolans, and a crude extract of wheat. All three beetle species showed evidence of olfaction. P. melanarius responded to all the odors except collembolans, H. rufipes responded to EBF and wheat, and N. brevicollis to collembolans. The use of a defence allomone as a prey-finding kairomone by certain carabid species has implications for pest management. Manipulation of predator chemical ecology by the inclusion of behavior-modifying compounds in a crop spray mix with reduced amounts of insecticide may allow for efficient aphid control with less environmental contamination.