Geographic and gender differences in semiochemicals in emerging adult southern pine beetle (Coleoptera: Scolytidae)

Abstract

Six semiochemicals, important in the communication system of southern pine beetle, Dendroctonus frontalis Zimmermann, were isolated from hindguts of individual beetles from Texas, South Carolina, and North Carolina. Females had more cis-verbenol (cV) and trans-verbenol (tV) than males, but males contained much more verbenone (V). Both sexes had the same amounts of frontalin (F), endo-brevicomin (eB), and α-pinene (αP). Geographic differences were found in quantities of tV and V in both sexes, and in αP and F in males only. Males produced predominantly (+)-F and (-)-eB, (-)-cV, and (-)-V; however, the enantiomeric composition of tV produced varied considerably geographically. In contrast, females produced predominantly (+)-cV and (+)-V and (-)-F, (-)-eB, and (-)-V. The (+) enantiomer of αP predominated in both sexes, but the percentege of (+)-αP was generally lower than that released from beetle-infested logs from the same areas. Geographic differences in enantiomeric composition of tV and V were significant in males, and of eB in females. Behavioral implications of the results are discussed.