3-Hydroxyhexan-2-one and 3-Methylthiopropan-1-ol as Pheromone Candidates for the South American Cerambycid Beetles Stizocera phtisica and Chydarteres dimidiatus dimidiatus, and Six Related Species

Here, we study the pheromone chemistry of two South American cerambycid beetle species, and their behavioral responses to candidate pheromone components. Adult males of Stizocera phtisica Gounelle (subfamily Cerambycinae: tribe Elaphidiini) produced a sex-specific blend of (R)-3-hydroxyhexan-2-one with lesser amounts of 3-methylthiopropan-1-ol. In field bioassays, traps baited with racemic 3-hydroxyhexan-2-one and 3-methylthiopropan-1-ol did not catch conspecific beetles, but did catch both sexes of a sympatric species, Chydarteres dimidiatus dimidiatus (F.) (Cerambycinae: Trachyderini). We found that males of this species also produce (R)-3-hydroxyhexan-2-one and 3-methylthiopropan-1-ol, and small amounts of 2-phenylethanol. Subsequent bioassays with these compounds showed that a blend of 3-hydroxyhexan-2-one and 3-methylthiopropan-1-ol constitutes the aggregation-sex pheromone of C. d. dimidiatus, with 2-phenylethanol not influencing the attraction of conspecifics. During the field bioassays, six other species in the Cerambycinae also were caught in significant numbers, including Aglaoschema ventrale (Germar) (tribe Compsocerini), congeners Chrysoprasis aurigena (Germar), Chrysoprasis linearis Bates, and an unidentified Chrysoprasis species (Dichophyiini), and Cotyclytus curvatus (Germar) and Itaclytus olivaceus (Laporte & Gory) (both Clytini), suggesting that one or more of the compounds tested are also pheromone components for these species.