Synthesis and Field Tests of Possible Minor Components of the Sex Pheromone of Prionus californicus Elin C. Maki & Joshua Rodstein & Jocelyn G. Millar & Karen S. Barbour & Lawrence M. Hanks & James D. Barbour Received: 29 March 2011 /Revised: 10 May 2011 /Accepted: 19 May 2011 # Springer Science+Business Media, LLC 2011 Abstract Earlier work has shown that adult male Prionus californicus Motschulsky (Coleoptera: Cerambycidae) are attracted to the female-produced compound (3R,5S)-3,5- dimethyldodecanoic acid, and to a synthetic mixture of the four stereoisomers of 3,5-dimethyldodecanoic acid. Here, we report the results of field trials that tested whether or not three structurally related compounds (methyl 3,5- dimethyldodecanoate, 3,5-dimethyltridecanoic acid, and 3,5-dimethylpentadecanoic acid), present in extracts of virgin females, are attractive, and whether or not they influence attraction to 3,5-dimethyldodecanoic acid. In a trial with single components, only traps baited with the acid or its methyl ester captured more beetles than did control traps; catches to the acid were five times higher than to the methyl ester. Another trial, excluding 3,5- dimethyldodecanoic acid, confirmed the activity of the methyl ester. Finally, addition of the three compounds to 3,5-dimethyldodecanoic acid, in the ratio found in extracts from female beetles, gave a catch similar to that of traps baited with 3,5-dimethyldodecanoic acid alone. Conse- quently, the function of these minor compounds remains undetermined. Key Words Prioninae . Pest management . Pheromone . (3R,5S)-3,5-dimethyldodecanoic acid . Coleoptera . Cerambycidae Introduction A number of insects including the herald moth, Scoliop- teryx libatrix L, and the peach twig borer, Anarsia lineatella Zeller, produce novel, branched alkanes, alkenes, and alcohols (Francke et al., 2000; Schlamp et al., 2005). Adult females of the cerambycid beetle Prionus californicus Motschulsky produce a volatile sex phero- mone, (3R,5S)-3,5-dimethyldodecanoic acid, to which males are strongly attracted, and which has potential as a management tool (Rodstein et al., 2009, 2011; Maki et al., 2011). Males responded as strongly to a synthetic mixture of the four stereoisomers of 3,5-dimethyldodecanoic acid as they did to the natural enantiomer, indicating that the unnatural stereoisomers were not inhibitory (Rodstein et al., 2011). Antennae of male P. californicus responded most strongly to 3,5-dimethydodecanoic acid in coupled gas chromatography-electroantennography (GC-EAD) studies, and also responded to three other compounds, the methyl ester of 3,5-dimethyldodecanoic acid and the homologs 3,5-dimethyltridecanoic acid and 3,5- dimethylpentadecanoic acid, that were present in solid phase microextraction (SPME) wipe samples of ovipositors Electronic supplementary material The online version of this article (doi:10.1007/s10886-011-9972-x) contains supplementary material, which is available to authorized users. E. C. Maki : K. S. Barbour : J. D. Barbour (*) Southwest Idaho Research & Extension Center, Parma, ID 83660–9637, USA e-mail: jbarbour@uidaho.edu J. G. Millar Department of Entomology, University of California, Riverside, CA 92521, USA J. Rodstein : J. G. Millar Department of Chemistry, University of California, Riverside, CA 92521, USA L. M. Hanks Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA J Chem Ecol DOI 10.1007/s10886-011-9972-x