Enantiomers of 2-Butyl Dodec-2-enoate as Sex Attractants

Interest in studying the pheromone systems of animals has been growing from year to year. The Zygaenidae family (Insecta, Lepidoptera) taken as a model group for our studies includes more than 1000 species, but the structure of sex pheromones and sex attractants were only identified for a small number of species in two of the five subfamilies. The analysis of the published data on the chemical composition and structure of the known Zygaenidae sex pheromones and sex attractants allowed us to reveal specific features of their molecular structure potentially affecting attractive properties. The targeted synthesis of potential sex attractants with the given structural features was carried out from dodecanoic acid and stereoisomers of the chiral 2-butanol. Attractive properties of the compounds, R- and S-enantiomers of 2-butyl dodec-2-enoate, as well as the optically inactive racemic mixture of these esters, were studied for seven years in 14 countries worldwide. R- and S-enantiomers of 2-butyl dodec-2-enoate were shown to be sex attractants for males of 22 Zygaenidae species from six genera: Theresimima Strand, 1917 (1 species), Illiberis Walker, 1854 (1 species), Goazrea Mollet, 2016 (1 species), Rhagades Wallengren, 1863 (3 species), Adscita Retzius, 1783 (9 species), and Jordanita Verity, 1946 (7 species). In addition, attractive properties of 2-butyl dodec-2-enoate were found for three species of other Insecta families: Argyresthia semifusca (Haworth, 1828) (Lepidoptera, Yponomeutidae), Dolicharthria stigmosalis (Herrich-Schaffer, 1848) (Lepidoptera, Crambidae), and Tilloidea unifasciata (Fabricius, 1787) (Coleoptera, Cleridae). Male olfactory receptors, which perceive chemical signals, can differentiate optical isomers. Some species were attracted mainly by the R-enantiomer of 2-butyl dodec-2-enoate; some, by the S-enantiomer, and for others, the racemic mixture was biologically active. Ecological and faunistic studies of new synthetic sex attractants supported the discovery of two new species and one genus of Procridinae (Zygaenidae). They also allowed clarification of distribution boundaries of rare species and studies of their biology. The use of the synthesized compounds for the detection and monitoring of seasonal dynamics of pest species counts (Theresimima ampellophaga (Bayle-Barelle, 1808), Rhagades (Rhagades) pruni ([Denis & Schiffermuller], 1775), Illiberis (Primilliberis) pruni Dyar, 1905) seems promising for optimization of pest control with consideration of modern environmental protection requirements. In addition, the data on the functioning and structures of Procridinae attractants in combination with traditional morphological and cytogenetic approaches can be used for the analysis of phylogenetic relationships and support biosystematics in Zygaenidae.