Enzymes in the diverse group known as cytochrome P450s have multiple important functions in insects, including detoxification of plant secondary metabolites and biosynthesis of pheromone components.  We used degenerate PCR primers, designed from highly conserved regions of deduced amino acid sequences of known insect P450 genes, to obtain ~420-450 b.p. fragments of at least nine putative P450 genes from cDNA derived from male California fivespined ips, Ips paraconfusus (Coleoptera:  Scolytidae), fed on ponderosa pine, Pinus ponderosa, phloem.  Comparisons with known P450s indicate that the putative I. paraconfusus P450s are from the Cyp4 family.  Male I. paraconfusus produces ipsenol and ipsdienol, two myrcene-derived monoterpene alcohols, as components of their aggregation pheromone.  It is possible that P450s play a role in the stereospecific biosynthesis of these pheromone components in I. paraconfusus and in other bark beetles.  We are currently working on obtaining full-length P450 genes for characterization of mature enzymes with numerous substrates, including myrcene.  We have also begun QPCR expression analyses to compare P450 transcript levels between male and female insects, between fed and unfed insects over time courses, and between juvenile hormone-treated and solvent-treated insects.  We expect that the results will provide new data that pertain to important events during host colonization in coniferophagous bark beetles.