Generic Pheromones Identified from Northern Hemisphere Cerambycidae (Coleoptera) Are Attractive to Native Longhorn Beetles from Central-Southern Chile

SIMPLE SUMMARY: In the family Cerambycidae, most attractant pheromones identified to date have come from species native to the northern hemisphere. Because many of the pheromone compounds are shared among related species, field tests of known pheromones in new regions have frequently attracted additional species whose pheromones have not yet been formally identified. Here, we report the results of field bioassays with previously identified cerambycid pheromones in Chile, where pheromones have not been identified for any native cerambycids to date. Trials were conducted in several different localities in central-southern Chile, testing eight compounds individually. Approximately 580 specimens were captured from eleven species, with Calydon submetallicum showing significant attraction only to 3-hydroxy-2-hexanone, whereas Eryphus laetus was significantly attracted to this compound, as well as to (2R*,3S*)-, and (2R*,3R*)-2,3-hexanediol. These compounds are likely aggregation pheromone compounds for these species, and can be exploited for monitoring and biological studies of the Chilean cerambycid fauna. ABSTRACT: We conducted field bioassays with several known cerambycid pheromones in two zones of central-southern Chile: (1) Las Trancas (Ñuble region) and Coñaripe (Los Rios region) (Study 1) and (2) Rucamanque and Maquehue (La Araucania region) (Study 2). Up to eight compounds were tested individually, including 3-hydroxy-2-hexanone, (2R*,3S*)- and (2R*,3R*)-2,3-hexanediol, fuscumol, fuscumol acetate, monochamol, 2-methylbutanol, and geranylacetone. Compounds were loaded in plastic sachets placed in either multiple funnel or cross-vane panel traps hung in trees in a randomized block design (n = 3 or 4). The number of treatments and bioassay periods varied depending on the study. A total of 578 specimens belonging to 11 native species were collected, with the three captured in the highest numbers being Eryphus laetus (292 specimens), Calydon submetallicum (n = 234), and Chenoderus testaceus (n = 20). The three species are of economic importance: E. laetus is considered a minor pest in apple orchards, and the other two species infest Nothophagus hosts, including some timber species. Traps baited with 3-hydroxy-2-hexanone collected significant numbers of both sexes of the two most abundant species, and this compound was the only treatment that attracted C. submetallicum. (2R*,3R*)- and (2R*,3S*)-2,3-Hexanediols were also significantly attractive to E. laetus. Our results suggested that 3-hydroxy-2-hexanone and 2,3-hexanediols, which are known pheromone components of cerambycid species worldwide, are also likely to be conserved aggregation pheromone components among some species in western South America.