Methionol as an aggregation-sex pheromone of the desert-dwelling beetle Eustromula valida (Coleoptera: Cerambycidae)

As part of a long-term project on unraveling the use of pheromones in the large beetle family Cerambycidae, field trials were conducted with generic blends of known cerambycid pheromones at a desert site in southern California. In the first year of testing (2022), the species Eustromula valida (LeConte) (subfamily Cerambycinae, tribe Elaphidiini) and Aethecerinus latecinctus (Horn) (Cerambycinae, Trachyderini) were weakly attracted to one of the lure blends. In follow-up trials in 2023, only E. valida were caught, and collection of volatiles from both sexes of E. valida determined that males sex-specifically produced 3-methylthiopropan-1-ol (methionol), a compound that was not in the tested lure blends. Beetles of both sexes were strongly and specifically attracted to this compound in field bioassays, verifying that it is an aggregation-sex pheromone. No sympatric species were attracted to methionol while it was deployed in the field. Several recent studies have identified methionol as a pheromone component for other cerambycid species in both North and South America, suggesting it may represent another common pheromone component within the Cerambycidae.