E. W. Underhill

Sex attractants for Geometrid and Noctuid moths

Male moths belonging to 17 species of Geometridae and nine species of Noctuidae were captured in traps baited with synthetic chemicals as part of a field screening program. The compounds tested were the C18-C22 homologs of: (1) (3Z,6Z,9Z)-triene hydrocarbons; (2) mixtures containing equal quantities of (3Z,6Z)-cis-9,10-expoxydienes, (3Z,92Z)-cis-6,7-epoxydienes, and (6Z,9Z)-cis-3,4-epoxydienes; (3) (3Z,6Z)-9S,10R-epoxydienes; (4) (3Z,6Z)-9R,10S-epoxydienes; and (5) (3Z,6Z,9Z,11E)-nonadecatetraene. Field captures and electroantennographic assays revealed a high degree of specificity in the responses of many species to the synthetic chemicals. In several species the ability of males to discriminate between the 9S,10R and 9R,10S enantiomers of the monoepoxydiene isomers was clearly shown. Synergists and inhibitors were discovered for several of the reported attractants, some of which were not previously known to have semiochemical activity. The geometrid moths captured includedEpirrhoe sperryi (Herbulot),Mesoleuca ruficillata (Guenée),Triphosa haesitata (Guenée),Metanema inatomaria (Guenée),Prochoerodes transversata (Drury),Cabera erythemaria (Guenée),Synaxis jubararia (Hulst),Dysstroma brunneata ethela (Hulst),Eulithes testata (Linnaeus),Sicya macularia (Harris),Xanthorhoe iduata (Guenée),X. abrasaria aquilonaria (Herrich-Schäffer),X. munitata (Hübner),Itame loricaria (Eversmann),Eupithecia annulata (Hulst),E. rovocastaliata (Packard) andE. satyrata dodata (Taylor). The noctuid moths captured includedBleptina caradrinalis (Guenée),Idia américalis (Guenée),I. aemula (Hübner),Rivula propinqualis (Guenée),Lomanaltes eductalis (Walker),Spargaloma sexpunctata (Grote),Caenurgina distincta (Neumuller),Euclidia cuspidea (Hübner), andZale duplicata (Bethune). Six of the nine noctuid species captured belong to three subfamilies for which sex attractants had not been reported previously. Details for the stereospecific synthesis of (3Z,6Z)-cis-9,10-epoxydienes are also reported.

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.

Triunsaturated hydrocarbons, sex pheromone components ofCaenurgina erechtea.

Abstract(Z,Z,Z)-3,6,9-Eicosatriene and (Z,Z,Z)-3,6,9-heneicosatriene have been identified as components of the sex pheromone of the noctuid,Caenurgina erechtea (Cramer), the forage looper. Structural assignments were made on the basis of spectroscopic and chromatographic data and were confirmed by comparison with synthetic material. Flight tunnel behavioral studies demonstrated that either component, when tested individually, would elicit wing fanning responses in males; however, mixtures of the two components increased this response and were essential for initiation of upwind flight and landing. In field experiments, traps baited with either component alone captured few or no adult forage looper males while those baited with both components captured several target males.

Sex pheromone components of three species ofSemiothisa (Geometridae), (Z,Z,Z)-3,6,9-heptadecatriene and two monoepoxydiene analogs

Adult males ofSemiothisa signaria dispuncta (Walker) were attracted to field traps baited with (Z,Z,Z)-3,6,9-octadecatriene and (Z,Z)-6,9-cis-3,4-epoxy-octadecadiene. However, analyses of sex pheromone gland extracts of females of this species by GC-MS and by GC in combination with an electroantennograph detector (GC-EAD) showed the pheromone to be comprised of a mixture of the next lower homologs: (Z,Z,Z)-3,6,9-heptadecatriene and (Z,Z)-6,9-cis-3,4-epoxy-heptadecadiene. Blends of these two C17 compounds were subsequently found to be more attractive to males in the field than the corresponding C18 mixtures. Sex pheromones of two otherSemiothisa species were also found to contain C17 components. (Z,Z,Z)-3,6,9-Heptadecatriene, detected by GC-EAD analysis of a female abdominal tip extract ofS. bicolorata (Fabricius), attracted conspecific males, and this attraction was significantly reduced by additions of (Z,Z)-6,9-cis-3,4-epoxyheptadecadiene, the major pheromone component ofS. signaria dispuncta, to the lure. (Z,Z)-3,9-cis-6,7-Epoxy-heptadecadiene was detected by GC-EAD analysis as the primary male antennal stimulatory component present in abdominal tip extracts ofS. ulsterata (Pearsall), and males of this species were attracted to traps baited with this epoxide. Each of these three C17 compounds constitute previously unknown lepidopteran sex pheromone components. Blends of (Z,Z, Z)-3,6,9-heptadecatriene and (Z,Z)-3,9-cis-6,7-epoxyheptadecadiene attracted males of a fourth species,S. delectata Hulst, but no females of this species were obtained to permit analysis of its sex pheromone. The occurrence of (Z,Z,Z)-3,6,9-heptadecatriene inS. neptaria (Guenee) females was indicated by GC-MS analysis of an abdominal tip extract; however, no males were attracted to any of the fielded mixtures containing this hydrocarbon.

Field trapping of diamondback mothPlutella xylostella using an improved four-component sex attractant blend

In addition to three known sex lure components [(Z)-11-hexadecenyl acetate, (Z)-11-hexadecenal, and (Z)-11-hexadecenol], (Z)-9-tetradecenyl acetate was field-proven as a trace coattractant for malePlutella xylostella, with an optimal content below 0.01% in blends. This potent four-component lure for diamondback males also attractedCrymodes devastator males, and in this respect is not different in its attractancy from virgin diamondback females. Replacement of (Z)-9-tetradecenyl acetate in the four component lure with (Z)-9-tetradecen-1-ol, at the level of 10% of the total lure mixture, did not alter its attractancy for diamondback males, but it did inhibit attraction ofCrymodes devastator. The status of biologically active components as possible sex pheromones or para-pheromones is discussed.

Sex pheromone components of fall cankerworm moth,Alsophila pometaria : Synthesis and field trapping.

Abstract(Z,Z,Z,E)-3,6,9,11-Nonadecatetraene and (Z,Z,Z,Z)-3,6,9,11-nonadecatetraene, sex pheromone components ofAlsophila pometaria, were synthesized by stereoselective Wittig reactions and found to be spectroscopically and chromatographically identical to isolated natural material. Flight-tunnel bioassays and field-trapping experiments confirmed that the two tetraenes together with (Z,Z,Z)-3,6,9-nonadecatriene are sex pheromone components. While traps baited with either tetraene individually captured conspecific males in field-trapping experiments, addition of the triene, which captured no males by itself, to either tetraene resulted in synergistic responses.

Attraction of tortricid moths of subfamily olethreutinae to field traps baited with dodecadienes.

All four geometrical isomers of 7,9- and 8,10-dodecadienes with acetate, alcohol, and aldehyde functional groups were synthesized and field tested. The field survey produced sex attractant lures for 14 insect species. Species in the generaCydia, Grapholita, Eucosma, Pelochrista, Petrova, Phenta, Hedya, and Pseudosciaphila were captured. Defined lures were developed for some of the species captured. Gas chromatographie retention times for all geometrical isomers of 7,9- and 8,10-dodecadienes with acetate, alcohol, and aldehyde functional groups are reported. A study of the isomerization of 8,10-dodecadienyl acetates and aldehydes impregnated in rubber septa is reported.

Trace co-attractants in synthetic sex lures for 22 noctuid moths

Trace components contributed significantly to the potency of synthetic sex attractant lures for males of many species of Noctuidae. Improved synthetic blends for 12 moths includingEuxoa ochrogaster andTrichoplusia ni, and new lure blends for 10 moths are described. In every case the trace constituents were structural analogs of the main lure components.

Identification and field testing of female-produced sex pheromone components of the spring cankerworm,Paleacrita vernata Peck (Lepidoptera: Geometridae).

Two sex pheromone components, 3(Z),6(Z),9(Z)-nonadecatriene (3Z,6Z,9Z-19 ∶ H), and 3(Z),6(Z),9(Z)-eicosatriene (3Z,6Z,9Z-20∶ H), have been positively identified, and a third component, 6(Z),9(Z)-nonadecadiene (6(Z),9(Z)-19 ∶ H) has been tentatively identified from abdominal tip extracts of female spring cankerworm moths,Paleacrita vernata Peck (Lepidoptera∶ Geometridae). The pheromone components were identified by a combination of gas chromatography, electroantennography, mass spectrometry, chemical tests, comparison with standards, and field testing. Only 3Z,6Z,9Z-20 ∶ H exhibited significant attractant activity when tested alone, and it was potentiated by the other two components. The attractive blend was an 8∶2∶1 ratio of 3Z,6Z,9Z-20∶H/3Z,6Z,9Z-19∶H/6Z,9Z-19∶H. However, the two-component blend of 3Z,6Z,9Z-20 ∶ H and 6Z,9Z-19 ∶ H (8∶1 ratio) was as attractive as the three-component blend in further field tests. A series of related compounds, the diene monoepoxides available from epoxidation of C19 and C20 3Z,6Z,9Z-trienes, some of which have been found in the pheromone blends of other moth species, were tested as behavioral antagonists. The attraction of male moths to synthetic lures was suppressed by the addition of 6Z,9Z-cis-3,4-epoxy-nonadecadiene to the lures. Additional experiments were performed to determine the effects of lure dosage, trap height, and trap design on the numbers of male moths captured.

Attraction of sphingid moths (Lepidoptera: Sphingidae) to 10,12-hexadecadienyl aldehydes and acetates: Evidence of pheromone components.

A field survey of 10,12-hexadecadienyl alcohols, acetates, and aldehydes showed attraction to a wide range of sphingid moths. Data are presented showing the attraction ofSmerinthus jamaicensis, Smerinthus cerisyi, Pachysphinx modesta, Hemaris diffinis, andProserpinus flavofasciata to these compounds. Mass spectral, EAG, and EAD data show evidence for the presence of these dienes in female extracts ofS. cerisyi, Hyles gallii, andSphinx drupiferarum.