Gábor Szöcs

Attraction of male turnip moths Agrotis segetum (Lepidoptera: Noctuidae) to sex pheromone components and their mixtures at 11 sites in Europe, Asia, and Africa

Selected combinations of (Z)-5-decenyl, (Z)-7-dodecenyl, and (Z)-9-tetradecenyl acetates, the pheromone components of the turnip mothAgrotisSegetum were tested for field attractancy at six, two, and three sites in Europe, Asia, and Africa, respectively. At all of the sites in Eurasia and in northern Africa the ternary mixture of the acetates captured most males, while at the sites south of the Sahara in Africa, (Z)-5-decenyl acetate alone was responsible for attraction. Differences in male attraction among the populations studied confirm the existence of significant population variation in the pheromone ofA. segetum. Interpretation of the present results together with earlier studies suggests that this variation is more or less continuous in Eurasia and north Africa, while a clearly distinct pheromone type is present in the areas south of the Sahara desert.

Pheromone variation among eastern European and a western Asian population of the turnip mothAgrotis segetum.

The female sex pheromone composition and the male electro-physiological response with respect to the three main sex pheromone components, (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-9-tetradecenyl acetate, were investigated in populations ofAgrotis segetum from Armenia and Bulgaria. The percentage composition of the female-produced pheromone was 1∶52∶47 and 1∶42∶57 for the respective populations. Corresponding male receptor frequencies were 9∶90∶1 and 6∶92∶2. EAG response profiles of the male antennae were similar for the two populations. The populations from Armenia and Bulgaria differed from the earlier investigated French and Swedish populations, which have larger amounts of (Z)-5-decenyl acetate in gland extracts and have a majority of (Z)-5-decenyl acetate-sensitive receptors. Investigation of receptor frequencies on antennae of male Hungarian moths showed that individuals could be classified as either Swedish or Armenian/Bulgarian type. Males of the Swedish type were preferentially attracted to the three-component pheromone blend, whereas blends of (Z)-7-dodecenyl and (Z)-9-tetradecenyl acetate, and (Z)-7-dodecenol [pure or in mixture with (Z)-5-decenol] attracted the Armenian/Bulgarian type. The nature of pheromone variation among European and Asian populations of the turnip moth and possible mechanisms maintaining the variation are discussed.

Field attraction ofAgrotis segetum males in four european countries to mixtures containing three homologous acetates

Abstract(Z)-5-Decenyl, (Z)-7-dodecenyl, and (Z)-9-tetradecenyl acetate were tested as single compounds and blends for field attraction to the turnip moth in Denmark, France, Hungary, and Switzerland. Best attraction was obtained when all three components were present. Attractants for other noctuids are described, e.g.,Meristis trigrammica, Hoplodrina alsines, Erastria trabealis, Euxoa nigricans, Axylia putris, andAutographa gamma, which were caught with some of the components and their blends.

Species discrimination in five species of winter-flying geometrids (Lepidoptera) based on chirality of semiochemicals and flight season

Enantiomer separation of (6Z,9Z)-cis-3,4-epoxynonadecadiene and (3Z,9Z)-cis-6,7-epoxynonadecadiene could be achieved using chiral high-resolution gas chromatography and a cyclodextrin-bond column. (3Z,9Z)-(6R,7S)-Epoxynonadecadiene was identified from ovipositor extracts ofColotois pen-Naria, while inErannis defoliaria the 6S,7R-enantiomer was found. In field trapping tests pure synthetic enantiomers caught only conspecific males of these species. (3Z,6Z,9Z)-Nonadecatriene was found in both species, while the presence of (3Z,6Z,9Z)-heneicosatriene was indicated inC. Pennaria only. A 10∶10∶3 blend of (3Z,9Z)-(6R,7S)-epoxynonadecadiene, (3Z,6Z,9Z)-heneicosatriene, and (3Z,6Z,9Z)-nonadecatriene was found to be optimal for catchingC. Pennaria, whileE. Defoliaria males were optimally caught by a 1∶1 mixture of (3Z,9Z)-(6S,7R)-epoxynonadecadiene and (3Z,6Z,9Z)-nona-decatriene. (6Z,9Z)-(3S,4R)-Epoxynonadecadiene was identified from ovipositor extracts ofAgriopis (Erannis) aurantiaria. In field tests the pure enantiomer proved to be a highly specific sex attractant for both the late autumn/early winter flyingA. Aurantiaria and the late winter/early spring flyingA. Leucophearia. Males ofAgriopis marginaria, which fly in late winter/early spring, were attracted to (3Z,9Z)-(6S,7R)-epoxynonadecadiene. The addition of (3Z,6Z,9Z)-nonadecatriene to theS,R-enantiomer increased captures. Optimal catches were recorded with a 10∶3 epoxide-hydrocarbon blend. Enantiomer specificity in all species was confirmed in EAG measurements.

Novel type of sex pheromone structure identified fromStigmella malella (Stainton) (Lepidoptera: Nepticulidae)

Short-chain unsaturated chiral methyl carbinols are identified as a new class of lepidopteran pheromone components. The natural female-produced pheromone of the banded apple pigmyStigmella malella (=Nepticula malella) (Stainton) (Lepidoptera: Nepticulidae) was identified to be a mixture of (S)-(E)-6,8-nonadien-2-ol and (S)-(Z)-6,8-nonadien-2-ol. For monitoring traps, a 10:3E:Z blend at 100–1000 µg is recommended. It is suggested that pheromones with similar structures may be specific to Nepticulidae and other related microlepidopteran families.

Electrophysiological and chemical analysis of sex pheromone communication system of the mottled umber,Erannis defoliaria (Lepidoptera: Geometridae)

Abstract(Z,Z,Z)-3,6,9-nonadecatriene (Z3,Z6,Z9–19Hy) and (Z,Z)-3,9-cis-6,7-epoxy-nonadecadiene (Z3,Z9-cis-6,7-epo-19Hy) were identified in pheromone gland extracts from femaleErannis defoliaria. The two components were found in a 1∶3 ratio, with the main component,Z3,Z9-cis-6,7-epo-19Hy present at an amount of about 1.5 ng per female. The components were identified by means of gas chromatography-mass spectrometry, gas chromatography-electroantennography and gas chromatography-single sensillum recordings. Single sensillum measurements on the male antenna showed two physiological types of sensilla. One type was characterized by a large spike amplitude cell responding toZ3,Z9-cis-6,7-epoxy-19Hy and a small spike amplitude cell responding toZ3,Z6,Z9–19Hy. A second type responded only with a large spike amplitude cell to the epoxide, and this cell was inhibited by the triene. Of the two pheromone components, the epoxide gave the higher response in the EAG tests. Preliminary field tests support the identification of the pheromone components. The epoxide was also found to be present in the extract of the pheromone gland ofColotois pennaria, and males ofC. pennaria andAgriopis marginaria were trapped by the mixture of the identified compounds.

Behavioral activity of optical isomers of 5,9-dimethylheptadecane, the sex pheromone ofLeucoptera scitella L. (Lepidoptera: Lyonetidae)

Among the pure stereoisomers of 5,9-dimethylheptadecane, a previously identified sex pheromone component ofLeucoptera scitella L., only theS,S isomer yielded trap captures in the field. The addition of the other stereoisomers had no effect on cathes. The addition of low percentages of racemic 5,9-dimethylhexadecane, a previously identified minor component in the sex pheromone, did not influence trap catches or alter behavior of males approaching an attractant source in the field.

Flight Tunnel Responses of Z Strain European Corn Borer Females to Corn and Hemp Plants

Abstract European corn borer females Ostrinia nubilalis Hübner (Lepidoptera, Pyralidae) exhibited upwind flight to three main host plants, corn Zea mays, hemp Cannabis sativa and hop Humulus lupulus, in a laboratory wind tunnel. Within a 15-min experimental period, 22.9% to 24.3% mated females flew toward and landed on a single potted corn plant. A potted hemp plant attracted 25.7% females. In a choice test, significantly more females landed on a hemp plant than on an adjacent corn plant. In contrast, paprika Capsicum annuum did not elicit attraction. Headspace collections from corn, hemp, and hop contained 18 compounds which consistently elicited a response from female antennae. Four of these, (Z)-3-hexenyl acetate, β-caryophyllene, (E)-β-farnesene, and (E,E)-α-farnesene co-occurred in three host plants studied. A 4-component blend of these compounds did not attract female moths in the wind tunnel. Availability of a wind tunnel bioassay is, however, a step toward the identification of plant volatiles guiding long-range attraction of gravid corn borer females.

Compounds modifying male responsiveness to main female sex pheromone component of the currant borer, Synanthedon tipuliformis Clerk (Lepidoptera: Sesiidae) under field conditions.

Various blends of (E,Z)-2,13-octadecadien-1-ol acetate (E,Z2,13-18: OAc), (Z)-13-octadecen-1-ol acetate (ZOAc) (two previously identified pheromone components of the currant borer,Synanthedon tipuliformis females), (E,Z)-, (Z,Z)-3,13-octadecadien-1-ol acetates (E,Z- andZ,Z3,13–18:OAc), andZ,Z-3,13-octadecadien-1-ol (Z,Z3,13–18:OH) were evaluated in field traps in three geographic regions. MaleS. tipuliformis were attracted toE,Z2,13–18:OAc in Tasmania, New Zealand, and Hungary. Captures were not influenced by the addition ofZ13–18: OAc, tested in Tasmania and Hungary. In Hungary and New Zealand, the addition ofE,Z3,13–18: OAc toE,Z2,13–18:OAc in a ratio of 100:3 was strongly synergistic; however, in Tasmania captures were reduced. The addition ofZ,Z3,13–18: OAc toE,Z2,13–18:OAc in a ratio of 10∶1 resulted in strong inhibition of trap captures in Hungary. WhenZ,Z3,13–18: OAc was added in different ratios to a 100:3 binary mixture ofE,Z2,13–18:OAc/E,Z3,13–18:OAc in Hungary, it strongly reduced captures at, or above a ratio of 100∶3∶3 but no decrease was recorded at a ratio of 100∶3∶1. In New Zealand and Tasmania it reduced captures at a ratio of 100∶3∶1. Observations of behavioral responses of maleS. tipuliformis in Hungary to synthetic baits in the field showed thatE,Z2,13–18:OAcby itself evoked close-range approaches to the source from only 20% of males, whereas the addition ofE,Z3,13–18:OAc in a ratio of 100∶3 raised that value to 65 %. Landing on the source was significant only at sources with a 100∶3∶0.1∶3∶10 blend ofE,Z2,13–18:OAc/E,Z3,13–18: OAc/Z,Z3,13–18: OAc/Z,Z3,13–18: OH/Z13–18: OAc. A 100∶3 binary mixture ofE,Z2,13–18:OAc/E,Z3,13–18:OAc in a dose range of 10–1000 μg can be recommended for more effective field monitoring ofS. tipuliformis populations in Hungary and in New Zealand. In Tasmania, at present,E,Z2,13–18: OAc by itself is the most potent sex attractant of the species.

Sex pheromone of the female currant borer, Synanthedon tipuliformis: Identification and field evaluation

(E,Z)‐2,13‐octadecadien‐1‐ol acetate and (Z)‐13‐octadecen‐1‐ol acetate have been identified from the ovipositor extracts of the currant borer, Synanthedon tipuliformis (Clerck), by capillary GC, and the structures were verified by GC‐MS. The diene/monoene ratio in the extract was found to be 93:7. Mixtures of these two compounds as well as the diene alone attracted conspecific males in the field.