Structure-activity relationships in sex attractants for north American noctuid moths

Sex attractants known for 145 species of noctuid moths have many common features both as to chemical constituents and to their relationships in blends. The great majority of constituents are straight-chain (Z)-alkenols, -alkenals, or -alkenyl acetates of even carbon number (10 through 16). The unsaturation is nonterminal in odd-numbered positions (5 through 11). In effective lures, these components are blended in specific ratios and the components in a sex pheromone or sex attractant blend are structurally related by "one-change" steps. This means that any blend component differs from one or more other components by a single structural alteration, such as a change in double bond position, or a change in carbon chain length, or a change in the oxygen function. For the few multicomponent systems known in detail, the central place in the "one-change" framework is occupied by the predominant blend component. Different patterns of occurrence of lure components occur in the subfamilies Acronictinae, Noctuinae, Hadeninae, Cuculliinae, Amphipyrinae, Heliothidinae, Plusiinae, Acontiinae, and Pantheinae, and some subfamilies are as yet without known lures. Some guiding principles for elucidation of blend compositions for unstudied species are presented; these guidelines can also be used in improvement of some synthetic blends of unsatisfactory quality.