Weevil Smelling Like a Moth: Bombykyl Acetate as the Aggregation-Sex Pheromone of the Brazilian Vanilla Pest, Montella sp. (Coleoptera: Curculionidae).

Beetles belonging to the Montella genus play a crucial role as pollinators for orchids. However, in Bahia state, Brazil, Montella sp. has been reported as a pest affecting Vanilla planifolia plantations, a highly economically valuable crop due to its status as the primary natural source of vanillin. Given the need for sustainable pest management strategies, this study aimed to identify the species' aggregation pheromone as a potential tool for monitoring and control. Through chromatographic analysis of volatiles released by males and females, two male-specific compounds were identified believed to be the species' aggregation pheromone based on behavioral experiments. The combination of analytical data and synthesis of standards allowed the identification of the main male-released semiochemical as the (10E,12Z)-hexadeca-10,12-dien-1-yl acetate (bombykyl acetate). Additionally, the minor compound (10E, 12Z)-hexadeca-10,12-dien-1-ol (bombykol), was also identified. Strikingly, these compounds are well-known lepidopteran pheromones, revealing a surprising trans-taxonomic convergence in chemical communication. To confirm the behavioral activity of these compounds in a weevil, Y-tube olfactometer assays were performed. Synthetic bombykyl acetate demonstrated strong attractivity for both sexes, confirming its role as the major aggregation-sex pheromone. This finding not only provides a foundation for the direct implementation of pheromone-based control methods but also challenges phylogenetic assumptions in chemical ecology.