The roles of host and non-host volatiles in the attraction of cerambycid beetles to pheromones

The past ten years has seen an explosion in the identification of pheromones for cerambycid beetles.  Field studies have shown that some species of cerambycids are attracted to pheromones alone, whereas others are attracted only by a blend of host volatiles with pheromones. To further explore this interaction between pheromones and host volatiles, and to determine the role of non-host volatile compounds in mate and host location of cerambycids, synthetic blends of tree volatiles with blends of cerambycid pheromones were assayed. Volatile compounds were identified from conifer and oak tree species by gas chromatography – mass spectrometry and synthetic blends mimicking conifer or oak volatiles were reconstructed. The resulting blends of pheromones and tree volatiles were tested in stands of different tree species composition in southern California.  Tree volatiles were released at three rates to identify the optimal release rate. Utilizing gas chromatography - electroantennogram detection and a subtractive field assay, the blends were further optimized by identifying synergistic and inhibitory groups of compounds. The trap data will be used to identify trends in ecology or phylogeny of cerambycid species that utilize host and nonhost volatiles in mediating attraction to pheromones.  Overall, our goal is to identify host volatiles for use in developing better attractants for cerambycid species.