Electroantennogram responses of the oriental fruit fly, Dacus dorsalis, to a spectrum of alcohol and aldehyde plant volatiles

Electroantennograms (EAGs) were recorded from unmated, laboratory-reared, male and female oriental fruit flies, Dacus dorsalis, in response to a range of between C₁ and C₁₂ carbon chain-length saturated and unaturated aliphatic alcohols and aldehydes, most all of which are known host-plant volatiles. Only two of the 35 compounds tested elicited significantly larger EAGs from female than male antennae. For the two functional-group series tested, aldehydes elicited responses greater than or equal to the responses to the alcohols. In general, the unsaturated alcohols did not elicit responses significantly different from the saturated alcohols. However, the unsaturated aldehydes, (E)-2-hexenal and 10-undecenal, elicited larger amplitude EAGs than their saturated analogs. EAGs were significantly greater for a particular carbon chain-length, with responsiveness to primary alcohols peaking at C₆ and aldehydes peaking at C₇. The (E)-2- monoenic alcohols peaked at C₆, while the (E)-3-alcohols plateaued between C₅ and C₈. The greatest EAG responses of all compounds tested were elicited by the saturated and unsaturated C₆ alcohols and aldehydes which are constitutents of the general green-leaf volatile complex that emanates from most plants. The potential adapative benefit of selective sensitivity to green-leaf volatiles is discussed in regards to foraging behaviors of oriental fruit flies.

---

Résumé Des électroantennogrammes (EAG) ont enregistré les réponses, en élevages de femelles et mâles vierges de Dacus dorsalis, à une gamme de chaînes de carbones de C₁ à C₁₂ saturés et non-saturés d'alcools aliphatiques et d'aldéhydes, dont beaucoup sont connus comme substances volatiles des végétaux. Seulement 2 des 35 composés examinés ont provoqué des EAG significativement plus importants chez les femelles que chez les mâles. Pour les séries des deux groupes fonctionnels examinés, les aldéhydes ont provoqué des réponses supérieures ou égales aux alcools. En général, les réponses aux alcools nonsaturés n'étaient pas significativement différentes des réponses aux alcools saturés. Cependant, les aldéhydes non-saturés, (E)-2-hexénal et 10-undécénal, ont induit des EAG de plus grande ampleur que leurs analogues saturés. Les EAG étaient significativement les plus importants pour une chaîne de longueur particulière, la réponse aux alcools primaires culminant en C₆ et les aldéhydes en C₇. Les alcools monoéniques (E)-2- culminaient en C₆, tandis que les alcools (E)-3- étaient étales entre C₅ et C₈. Les EAG les plus importants ont été obtenus pour tous les composés examinés avec les alcools et aldéhydes en C₆ qui appartiennent à l'odeur verte complexe émise par beaucoup de plantes. Le bénéfice adaptatif potentiel de la sensibilité sélective à l'odeur verte des feuilles est examinée en fonction du comportement de prospection de D. dorsalis.

     

Olfactory antennal responses to plant volatiles in apterous virginoparae of the vetch aphidMegoura viciae

Electroantennogram (EAG) responses were recorded from apterous virginoparae of the vetch aphidMegoura viciae Buckton (Homoptera, Aphididae) to more than eighty volatile compounds in order to investigate its sensory ability to perceive plant odours. The response profile ofM. viciae reveals a differential sensitivity for the array of plant volatiles tested. The whole group of general green leaf volatiles is very stimulatory. In addition to (E)-2-hexenal, the following compounds of this group elicit large EAG responses: (E)-2-heptenal, 1-octenol-3, hexyl acetate, (Z)-3-hexenyl acetate, hexanol-1, hexanal, 2-heptanone and 3-octanone. Relatively large EAGs are also produced by 4-methoxybenzaldehyde (p-anisaldehyde), hexanonitrile, heptanonitrile, 1,6-hexanedithiol, butyl isothiocyanate, 4-pentenyl isothiocyanate, (−)-(1S)-β-pinene, (+)-(S)-carvone, (−)-(R)-carvone, α-terpineol, linalool and citronellal. The nitriles are the most effective of all plant volatiles tested. Structure-activity relationships occur in various groups of chemicals and members of the green leaf volatiles, benzaldehydes, isothiocyanates and monoterpenes are ranked accordingly. In the group of green leaf volatiles, aliphatic aldehydes are more stimulating than the corresponding alcohols. EAG responses to series of saturated aliphatic alcohols and aldehydes reveal that C₆ and C₇ compounds are the most stimulatory. Dose-response curves show that the rank order of EAG response amplitudes hardly changes at lower dosages. It is concluded thatM. viciae perceives general plant volatiles as well as more-specific components, such as nitriles and isothiocyanates, associated with the odour blends of non-host plant species.     

Electroantennogram responses of the Mediterranean fruit fly, Ceratitis capitata, to the volatile constituents of nectarines

Electroantennograms (EAGs) were recorded from laboratory-reared, male and female Ceratitis capitata (medfly) in response to individual volatiles identified from ripe nectarines. Uniformity in EAG response between the sexes was observed for most test compounds. Only 10 volatiles, of the 44 nectarine volatiles tested, elicited significantly different EAG responses between the sexes. No correlation was observed between the magnitude of antennal responsiveness and the concentration of a particular volatile in the headspace odor of ripe nectarines. The most abundant (major) nectarine volatiles were among the least EAG stimulatory compounds tested. And certain minor and trace volatiles were the most potent compounds in eliciting EAGs. Moreover, the magnitude of antennal response to a nectarine volatile was related to the functional-group, chain-length, and unsaturation of the compound. The degree of potency of the compounds was as follows: six-carbon unsaturated aldehydes and alcoholsmethyl and ethyl hexanoates and octanoateshexenyl acetates and monoterpenes>shorter chain-length acetates and alcohols>lactones. Unsaturated aldehydes, alcohols, and acetates generally elicited larger EAGs than their saturated analogs, with the (E)-2-isomers being the most potent isomeric configurations. In addition, medfly antennae exhibited long recovery periods (i.e., >10 sec.) for the EAG tracings to return to baseline potential after stimulations with certain classes of compounds, e.g., C₆ to C₈ acid esters, monoterpenes, and hexen-1-ols. The potential adaptiveness to medflies for selective sensitivity to these volatiles is discussed.     

A re-examination of corn (Zea mays L.) ear volatiles

Helicoverpa zea (Boddie) is a major insect pest of corn and other agricultural crops. An improved understanding of semiochemcials that control adult behavior is needed to develop alternative control measures. In this study, overnight SPME collection of volatiles from corn ears enclosed in Teflon bags in the field at two stages of development were made. C₈–C₁₀ aldehydes, a C₈-alcohol, C₆–C₉ alcohol acetates, and numerous monoterpenes, sesquiterpenes, sequiterpene alcohols, and geosmin were identified after thermal desorption and GC/MS. Structural assignments of the alcohol acetates, Z-3-hexenyl acetate, 2-heptyl acetate, 2-nonyl acetate, and 4-nonyl acetate, the monoterpenes, α- and β-ocimene, and geosmin were made by analysis of standards that were purchased or prepared in the laboratory. All other assignments were based on published Kovat’s retention time indices (KI) and mass spectra. Pair-wise comparison of the relative amounts of each component between two groups of corn ears defined by silk weight did not identify significant differences, thus it is unknown whether or not silk weight impacted volatile emission composition and rate. To our knowledge three compounds detected in SPME collections, 2-heptyl acetate, 2-nonyl acetate, and 4-nonyl acetate have not been previously reported in corn ear or silk volatiles. Their impact on the flight response of gravid earworm females was evaluated in a flight chamber. No significant response to the individual compounds or a blend of all three was observed. Thus, their impact on moth behavior remains uncertain.     

Hickory shuckworm Cydia caryana: electroantennogram and flight tunnel studies of potential sex pheromone components

Electroantennogram (EAG) measurement of male Cydia caryana moth antennal olfactory response to monounsaturated 12 and 14 carbon alcohols and acetates indicated that the (E)-8-, (E)-10- conjugated double bond system of a dodecadien-1-ol acetate is a critical chemical structural component of the C. caryana sex pheromone. Additionally, EAG measurements implicated (E)-8-dodecen-1-ol acetate, (Z)-8-dodecen-1-ol acetate, (Z)-9-dodecen-1-ol acetate and (Z)-12-tetradecen-1-ol as potential minor pheromonal components. An EAG dosage-response study suggested that there were at least two heterologous populations of pheromone acceptors. Behavioral analysis of male moth response in a flight tunnel to compounds which evoked the stronger EAG responses suggested that (E,E)-8,10-dodecadien-1-ol acetate and (Z)-9-dodecen-1-ol acetate resemble or are C. caryana sex pheromonal components, while (Z)-8-dodecen-1-ol acetate and (E)-10-dodecen-1-ol acetate are either parapheromones or are minor pheromone components. Behavioral significance of (Z)-12-tetradecen-1-ol was difficult to interpret in the flight tunnel.

---

Résumé Les réponses olfactives antennaires de Cydia caryana, mesurées par électroantennogrammes (EAG), aux alcools et acétates à carbones monounsaturés en positions 12 et 14, ont montré que le système conjugué de double liaison, (E)-8-, (E)-10- du dodecadien-1-ol acétate constitue un composé chimique strutural critique de la phéromone sexuelle de C. caryana.De plus, les acétates: (E)-8-dodecen-1-ol,(Z)-8-dodecen-1-ol,(Z)-9-dodecen-1-ol, et le (Z)-12-tetradecen-1-ol, se sont révélés en AEG comme des composés secondaires de la phéromone. L'étude par AEG de la relation dose-réponse a conduit à l'hypothèse de deux catégories de populations de récepteurs de phéromones. L'analyse comportementale des résponses des papillons mâles dans le tunnel de vol aux composés qui ont provoqués les plus forts AEG, on fait estimer que les acétates (E,E)-8,10-dodécadien-1-ol et (Z)-9-dodecen-1-ol ressemblent (ou sont) les constituants de la phéromone sexuelle de C. caryana; tandis que les (Z)-8-dodecen-1-ol et (E)-10-dodecen-1-ol sont, soit des paraphéromones, soit des constituants mineurs de la phéromone.La signification biologique du (Z)-12-tétradécen-1-ol a été difficile à interprêter avec les expériences en tunnel de vol.

     

Identification by gas chromatography and mass spectrometry of lipids from the rat Harderian gland

Lipids from rat Harderian glands were extracted with ethyl acetate, hydrolysed with base and examined by gas chromatography (GC) and gas chromatography—mass spectrometry (GC—MS) as trimethylsilyl (TMS), [²H₉]TMS, methyl ester—TMS, picolinyl, nicotinate and nicotinylidene derivatives. The latter three derivatives were used to reveal the structures of the alkyl chains of fatty acids, alcohols and glycerol ethers, respectively. Forty-eight compounds were identified, representing about 97% of the total extracted lipids as measured by GC peak areas. The major constituents were fatty acids with chain lengths from 12 to 22 carbon atoms (mainly C₁₈ and C₂₀) and fatty alcohols (C₁₆ to C₂₆) derived from wax esters. Most of these acids and alcohols were unsaturated in the ω-7 position and were accompanied by smaller amounts of the saturated and ω-5 monounsaturated analogues. Glycerol ethers were also identified for the first time in this secretion; the ether chains contained from 14 to 19 carbon atoms (mainly 16) and were straight-chain saturated, unsaturated (ω-5 and ω-7) and branched (iso). The only sterol found was cholesterol amounting to 1.24% of the total extract.     

(Z)-8-dodecenyl acetate: the major component of the female sex pheromone of Cryptophlebia batrachopa, a Tortricid pest of macadamia in Malawi

Ovipositor washings from virgin female Cryptophlebia batrachopa (Meyrick) (Lepidoptera: Tortricidae) were analysed by gas chromatography (GC) linked to electroantennography (EAG) and by high-resolution GC. The major EAG-active component in ovipositor washings was shown to be (Z)-8-dodecenyl acetate with less than 0.5% of the E isomer. GC analysis of ovipositor washings from C. leucotreta confirmed the presence of approximately equal amounts of (Z)- and (E)-8-dodecenyl acetates (Persoons et al., 1977). When pure (Z)-8-dodecenyl acetate and mixtures containing up to 50% of the E isomer were tested in the field in Malawi where both Cryptophlebia species occurred, C. batrachopa male moths were caught only in traps baited with 10% or less of the E isomer and highest catches were recorded for the pure Z isomer. By contrast C. leucotretra males were caught predominantly by traps baited with more than 10% E isomer and no catches were recorded for the pure Z isomer. (Z)-8-dodecenyl acetate containing 1% of the E isomer was found to attract male moths of Opogona spp.

---

Résumé Les produits recueillis par lavages de l'ovipositeur de Cryptophlebia batrachopa Meyr. (Lep. Tortricidae) ont été analysés par chromatographie gazeuse (GC) associée à l'électroantennographie (EAG) et la GC à haute résolution. Le principal constituant actif en EAG provenant des lavages s'est révélé être le (Z)-8-dodécényl acétate avec moins de 0,5% de l'isomère E. L'analyse GC de ces produits de lavage de C. leucotreta ont confirmé la présence d'à peu près les mêmes quantités de (Z) et (E)-8-dodécényl acétates (Persoons et al., 1977). Quand des essais sur le terrain ont été effectués au Malawi, où existent les deux espèces de Cryptophlebia, avec du (Z)-8-dodécényl acétate et des mélanges comprenant jusqu'à 50% de l'isomère E, des mâles de C. batrachopa ont seuls été capturés dans des pièges contenant 10% ou moins de l'isomère E; les captures les plus élevées ont été obtenues avec l'isomère Z pur. A l'opposé, surtout des mâles de C. leucotreta ont été capturés dans des pièges garnis avec plus de 10% d'isomère E, et aucune capture n'a été obtenue avec l'isomère Z pur. Des mâles d'Opogona spp. ont été attirés par du (Z)-8-dodécényl acétate contenant 1% de l'isomère E.

     

Comparison of the olfactory sensitivity of two sympatric steppe grasshopper species (Orthoptera: Acrididae) to plant volatile compounds

Electroantennogram (EAG) responses of male and female Oedipodinae grasshoppers, Oedaleus decorus asiaticus B.-Bienko and Angaracris barabensis Pall to 37 plant volatile compounds were recorded. The two species have sympatric distribution and synchronous seasonal activity in Inner Mongolia Grasslands. They have different host plant preference with Oedaleus decorus asiaticus graminivorous and A. barabensis forbivorous. The EAG response profiles to 37 compounds of the two species and their both sexes were similar. Most of the green leaf volatiles elicited higher EAG responses in both species and sexes than terpenic compounds and some aromatic compounds. Strong EAG responses were elicited by 6-carbon alcohols (1-hexanol, Z-hexen-2-ol-1, E-2-hexen-1-ol, E-hexen-3-ol-1), aldehyde (E-2-hexen-1-al), ester (Z-hexen-3-yl acetate), and 7-carbon alcohols (1-heptanol) in both species and sexes. Monoterpenes with functional groups of alcohols and aldehydes were more stimulating than other monoterpenes tested. The sesquiterpenes tested elicited relatively low responses. Benzaldehyde elicited the highest responses for both species among aromatic components. Oedaleus decorus asiaticus showed higher EAG responses than A. barabensis to the green leaf volatiles, 1-decanol, 1-nonanol, 1-pentanol, hexanal, Z-hexen-3-yl acetate and to the sesquiterpenes (-)-trans-caryophyllene. Males have higher responses than females in Oedaleus decorus asiaticus. No sexual difference was observed in A. barabensis. Dose-dependent responses to six selected chemicals were observed from females. In both species, all the chemicals tested elicit EAG responses at concentration between 10^-3 mol/L and 10^-2 mol/L, except that the responses of A. barabensis to terpineol had a threshold concentration of 10-2 mol/L benzaldehyde and 1-hexanol had the highest slopes in dose curves, while 1-octen-3-ol showed the smallest slope in responses to the six chemicals tested. Comparative studies on the responses of two antennal sections and the whole antenna to six selected chemicals were carried out using females of both species. A significant EAG response was only recorded from the distal part of the antenna and not from the proximal seven segments.     

Effect of Alcohols,Aldehydes and their Derivatives to Induce Nutritional Encephalomalacia in Starting Chicks

n-Decyl (C₁₀), undecyl (C₁₁), lauryl (C₁₂) and myristyl (C₁₄) alcohols induced nutritional encephalomalacia, when fed to one-day-old White Leghorn male chicks for 3 weeks, while n-heptyl (C₇), n-octyl (C₈), n-nonyl (C₉), cetyl (C₁₆) and stearyl (C₁₈) alcohols did not. Esters of the former group, i.e. n-decyl acetate, lauryl stearate and dilauryl succinate, and aldehydes corresponding to the former group, i.e. n-decyl aldehyde and lauraldehyde, also had the ability to induce encephalomalacia. The disease can be completely prevented by dietary supplementation of dl-β-tocopheryl acetate. Median lethal dietary level of n-decyl and lauryl alcohols and lauraldehyde was estimated to be 20, 18, and 12% respectively.     

Identification of In-Chain-Functionalized Compounds and Methyl-Branched Alkanes in Cuticular Waxes of Triticum aestivum cv. Bethlehem

In this work, cuticular waxes from flag leaf blades and peduncles of Triticum aestivum cv. Bethlehem were investigated in search for novel wax compounds. Seven wax compound classes were detected that had previously not been reported, and their structures were elucidated using gas chromatography-mass spectrometry of various derivatives. Six of the classes were identified as series of homologs differing by two methylene units, while the seventh was a homologous series with homologs with single methylene unit differences. In the waxes of flag leaf blades, secondary alcohols (predominantly C₂₇ and C₃₃), primary/secondary diols (predominantly C₂₈) and esters of primary/secondary diols (predominantly C₅₀, combining C₂₈ diol with C₂₂ acid) were found, all sharing similar secondary hydroxyl group positions at and around C-12 or ω-12. 7- and 8-hydroxy-2-alkanol esters (predominantly C₃₅), 7- and 8-oxo-2-alkanol esters (predominantly C₃₅), and 4-alkylbutan-4-olides (predominantly C₂₈) were found both in flag leaf and peduncle wax mixtures. Finally, a series of even- and odd-numbered alkane homologs was identified in both leaf and peduncle waxes, with an internal methyl branch preferentially on C-11 and C-13 of homologs with even total carbon number and on C-12 of odd-numbered homologs. Biosynthetic pathways are suggested for all compounds, based on common structural features and matching chain length profiles with other wheat wax compound classes.     

Electroantennogram response gradient on the antenna of the European corn borer, Ostrinia nubilalis

The electroantennogram (EAG) response of male moths of the European corn borer (Ostrinia nubilalis) to their two pheromone components, (Z)- and (E)-11-tetradecenyl acetates, were studied. The EAG amplitude of the fast initial phase was approximately proportional to the antennal length. Local EAG responses were obtained along the length of the antenna with multiple electrodes. Response-interaction studies indicated a unique spread of the EAG response in a proximal direction in the antenna. A possible mechanism of the EAG summation was considered. The EAG response characteristic was similar for both (Z)- and (E)-11-tetradecenyl acetate along the length of the antenna.     

Conversion of Some Saturated Fatty Acids,Aldehydes, and Alcohols into γ- and δ-Lactones

A series or γ- and δ-lactones could be found in the thermal oxidative products of normal saturated acids, aldehydes, and alcohols (C₉, C₁₀, and C₁₂, respectively) heated at 180°C in the presence of 0.1% KMnO₄. Their lactones were identified by gas chromatography, infrared spectroscopy, and mass spectroscopy. And they could be detected also in the volatile compounds occurred by heating of C₁₀ acid, aldehyde, and alcohol mixed with pork fat. So it was expected that lactones in meat fat flavor described in the earlier papers could be secondary products converted from saturated acids, aldehydes, and alcohols formed by oxidative degradation of meat fats. This process was presumed to be one of the mechanisms of the lactone formation.

It was discussed that lactones might be derived through mono or dihydroperoxides of acids, aldehydes, and alcohols.     

The role of alcohols in pheromone biosynthesis by two noctuid moths that use acetate pheromone components

Primary alcohols varying in chain length from C₁₃ to C₁₆, and in number, position, and geometric configuration of double bonds, were applied in dimethyl sulfoxide to the surface of the female sex pheromone glands of Heliothis subflexa (Gn.) and Hydraecia micacea (Esper). Capillary gas chromatographic analysis of extracts of the treated glands indicated that the alcohols were converted to the corresponding aldehydes by H. subflexa females and to the acetates by H. micacea females. Conversions of the alcohols showed no preferences for molecular weight, number, position, or geometry of the double bonds in either species. Application of the acetates of the primary alcohols to the gland surface of H. subflexa females resulted in the production of both the corresponding alcohols and aldehydes, while neither alcohols nor aldheydes were produced when acetates were applied to the glands of H. micacea. In addition, application of the acetates to the gland surface of Heliothis virescens (F.) resulted in the production of both the corresponding alcohols and aldehydes. However, no evidence was found to indicate that acetates are ever produced by the pheromone gland of females of H. virescens.     

Sex pheromone of the Asian corn borer moth

By 1975, insect sex pheromones had been identified from 60 species (1) of moths (Lepidoptera), and nearly all of the 40 compounds involved had been found to be mono- or di-unsaturated C₁₀ to C₁₈ straight-chain aldehydes, alcohols, or acetates, and the sites of olefinic unsaturation were, with one exception (2), at odd-numbered positions in the carbon chain. Since that time, many more lepidopteran pheromone components have been identified, and mono-unsaturated compounds with unsaturation at even-numbered positions in the carbon chain remain extremely rare (3–6). However, in females of $\text{Ostrinia furnacalis}$ (Guenee), called the Asian corn borer, we have discovered another mono-olefinic lepidopteran sex pheromone that has the site of unsaturation at ab even carbon position. Females of this corn-pest species produce a $\text{ca}$. 1:1 geometric mixture of ($\text{Z}$)- and ($\text{E}$)- 12-tetradecen-1-o1 acetate to attract and sexually stimulate males. On the other hand, the nearest taxonomic relative (7) of the Asian corn borer, the European corn borer, $\text{Ostrinia nubilalis}$ (Hübner), uses a mixture of ($\text{Z}$)- and ($\text{E}$)-11-tetradecen-1-o1 acetate as its sex pheromone (8). Biochemical explanation of the paucity of monounsaturated moth sex pheromones with olefinic sites at even numbered carbon positions remains to be elucidated.     

Sex pheromone of Sparganothis pilleriana: E- and Z-11-Tetradecenyl acetates as essential components

Female sex pheromone gland extracts of Sparganothis pilleriana contain E-9-dodecenyl acetate, E-11-tetradecenyl acetate, Z-11-tetradecenyl acetate and saturated acetates of 12 to 24 carbons. Addition of E-9-dodecen-1-ol to the blend of the three unsaturated acetates is necessary to obtain maximum male catch.

---

Zusammenfassung Weibliche Sexualpheromondrüsen des Spring-wurmwicklers S. pilleriana enthalten E-9-Dodecenylacetat, E-11-Tetradecenylacetat und Z-11-Tetradecenylacetat neben gesättigten Acetaten mit 12 bis 24 Kohlenstoffeinheiten. Die beste Lockwirkung auf Männchen des Springwurmwicklers wird erzielt, wenn man dem Gemisch der drei ungesättigten Acetate E-9-Dodecen-1-ol zufügt, welches als elektrophysiologisch hoch wirksam bekannt ist, aber in den Drüsen nicht nachgewiesen werden konnte.

     

Biosynthesis of Bisorbicillinoid in Trichoderma sp. USF-2690; Evidence for the Biosynthetic Pathway,via Sorbicillinol,of Sorbicillin,Bisorbicillinol, Bisorbibutenolide,and…

An incorporation study of [1-¹³C] and [1,2-¹³C₂] labeled sodium acetates into sorbicillinol 1 established a ring closure system between C-1 and C-6 and the positions that were oxidized and/or methylated on a hexaketide chain. Subsequent investigations, using ¹³C-labeled 1 prepared from [1-¹³C] labeled sodium acetate, clearly demonstrated that both bisorbicillinol 2 and sorbicillin 6 incorporated ¹³C-labeled 1 into their carbon skeletons. ¹³C-labeled bisorbicillinols 2 derived from [1-¹³C]- and [2-¹³C]-labeled sodium acetates clearly indicate that these were on the biosynthetic route from 1 to bisorbibutenolide (bislongiquinolide) 3 and bisorbicillinolide 4 via 2 as a branching point in the fungus.     

Isolation and identification of cuticular compounds from the mediterranean flour moth,Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), their antibacterial activities and biological functions

Cuticular analysis of Ephestia kuehniella females by gas chromatography-mass spectrometry revealed the presence of four groups of chemical compounds including alkane, alcohol, aldehyde and fatty acid. The cuticular n-alkanes ranged from 12 to 18, 20, 23, 24 and 29 carbon atoms in the chain. The most abundant n-alkanes detected in the cuticular extracts were C₁₄ (14.98%) and C₁₈ (8.15%). Cuticular fatty acids included hexadecenoic acid, 9-octadecenoic acid and 9,12-octadecenoic acid. Two types of alcohol including, 2-methyl-Z,Z-3,13-octadecadienol and 9-methyl-Z-10-tetradecen-1-ol acetate, were found in the cuticular lipids of the females. Two aldehyde components, (E)-11-hexadecenal and 9,17-octadecadienal, were identified in the cuticular extract of E. kuehniella. Antibacterial activity of the cuticular compounds was tested against Bacillus subtilis, Bacillus thuringiensis and Escherichia coli. These compounds from the moths inhibited the growth of Gram-positive bacteria. The functional characteristics of the cuticular compounds operating as pheromones, species-associated compounds and host-resistant compounds to bacterial infection are discussed.     

Identification of a four-component sex pheromone blend in Bonagota cranaodes (Lepidoptera: Tortricidae)

Analysis of sex pheromone glands of the apple leafroller Bonagota cranaodes Meyrick by gas chromatography coupled with mass spectrometry or electroantennographic detection showed the presence of 14 structurally related acetates and alcohols of the chain length 10-18, including the main pheromone component (E,Z)-3,5-dodecadienyl acetate (E3,Z5-12Ac). Male antennae responded to the main compound, its Z,Z isomer, (E,Z) -3,5-tetradecadienyl acetate (E3,Z5-14Ac), and the monoenes (Z)-5-dodecenyl acetate (Z5-12Ac) and (Z)-9-hexadecenyl acetate (Z9-16Ac). Traps baited with a four-component blend of E3,Z5-12Ac, Z5-12Ac, E3,Z5-14Ac, and Z9-16Ac in a 100:5:5:100 ratio were significantly more attractive than the main compound alone. This improved trap lure is more suitable for monitoring population densities of B. cranaodes, and for detection of the onset of the seasonal flight period. A more complete pheromone blend is of importance also with respect to current attempts to develop mating disruption for control of this major pest of apple in Brazil.     

Electrophysiological and behavioural responses of Melolontha melolontha to saturated and unsaturated aliphatic alcohols

Male Melolontha cockchafers are known to use green leaf volatiles induced by female feeding on host plants for their mate location. Earlier studies of the response of the European cockchafer, Melolontha melolontha L. (Coleoptera: Scarabaeidae), to different green leaf aldehydes, alcohols, and acetates revealed that only green leaf alcohols were attractive to males in the field. Females were not attracted at all by these volatiles. Here, we present a study that aimed to elucidate the structure–activity relationships of aliphatic alcohols. Both behavioural and physiological responses were studied in male and female M. melolontha by field tests and electroantennography. The compounds tested were saturated aliphatic alcohols with chain lengths between five and eight carbon atoms. Furthermore, the cockchafer's response to six‐carbon alcohols with (E)‐2‐, (E)‐3‐, (Z)‐2‐, (Z)‐3‐, and (Z)‐4‐configurated double bonds was tested. All compounds elicited dose‐dependent responses on the antennae of both sexes. In general, males showed a stronger normalized EAG response to the stimuli than females. However, only the naturally occurring six‐carbon alcohols, i.e., 1‐hexanol (E)‐2‐, (Z)‐3, and (E)‐3‐hexen‐1‐ol were attractive to M. melolontha males in the field. Females were not attracted to any of the tested compounds, confirming previous results on the olfactory orientation of Melolontha cockchafers.     

A Selective Method of Estimation of Bacitracin in the Presence of Other Antibiotics and Growth Factors

The plum cankerworm moth, Cystidia couaggaria couaggaria (Geometridae: Ennominae), is a defoliator of Chinese plum trees (Prunus mume). The pheromone components of the female were analyzed by gas chromatography (GC) with an electro-antennographic (EAG) detector and GC coupled with mass spectrometry. The crude pheromone extract included several EAG-active components, i.e., trienyl, dienyl, and saturated hydrocarbons, with a C₂₁–C₂₅ straight chain. The characteristic mass spectra indicated the unsaturated hydrocarbons to be (3Z,6Z,9Z)-3,6,9-trienes and (6Z,9Z)-6,9-dienes. In the fields, mixtures of the synthetic C₂₁ and C₂₃ trienes in a ratio of 2:3 and 1:4 successfully attracted males of this diurnal species during daytime. While the male antennae responded to the C₂₅ triene and saturated hydrocarbons, their synergistic effects were not observed on the male attraction in the fields. Addition of the C₂₁ diene interestingly inhibited the activity of the triene mixture. Males of Cystidia truncangulata, a sympatric diurnal congener of C. c. couaggaria, showed similar EAG responses to the unsaturated hydrocarbons, but no C. truncangulata males were attracted by the lures tested for C. c. couaggaria males, indicating that the identified hydrocarbons comprised the species-specific pheromone of C. c. couaggaria females.