Pheromones in red pine cone beetle,Conophthorus resinosae hopkins,and its synonym,C. banksianae McPherson (Coleoptera: Scolytidae)

Analyses of abdominal extracts and beetle-produced volatiles revealed that femaleConophthorus resinosae andC. banksianae produced optically pure (E)-(+)-pityol (2R,5S)-(+)-2-(1-hydroxy-1-methylethyl)-5-methyltetrahydrofuran]. In field tests, traps baited with (E)-(±)- or (E)-(+)-pityol captured only males. Addition of host oils to traps baited with pityol did not significantly enhance the capture of males. Males of these former sibling species produced the spiroacetal (5S,7S)-(–)-7-methyl-1,6-dioxaspiro4.5]decane with high optical purity (96%). Addition of the racemate or the optical isomers of the spiroacetal to traps baited with (E)-(±)-pityol almost completely inhibited the capture of males. It is hypothesized that to ensure their reproductive success, males produce the spiroacetal to repel rival males. Species specificity in pityol and the spiroacetal was not found betweenC. resinosae andC. banksianae, thus supporting their synonymy.