Mechanisms of premating isolation between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae)

Helicoverpa armigera and Helicoverpa assulta are sympatric sibling species, and in the laboratory they can interbreed and produce viable offspring. To assess the contributions of temporal barriers and sexual barriers to premating isolation, we investigated both the temporal rhythms of calling behavior and pheromone titers of H. armigera and H. assulta females and the behavioral responses of males to conspecific and heterospecific calling females in a wind tunnel. Both H. armigera and H. assulta females called throughout the scotophase, and there was more calling during the second half of the scotophase than during the first half. Maximal pheromone titer and maximal calling activity in H. armigera synchronously occurred at the sixth hour into the scotophase, whereas, in H. assulta, the maximal pheromone titer occurred 2 h before the peak of calling. Pheromone blend ratios of the two species were opposite and, within each species, changes in the ratio within the scotophase and at different ages were relatively small. Males of both H. armigera and H. assulta responded strongly to their conspecific calling females in the wind tunnel and completed the whole courtship sequence. In contrast, they did not land and had no copulation attempts in response to heterospecific calling females. These results show that the two species do not have obvious temporal differences in calling behavior and pheromone production, and the specificity of sex pheromone blend emitted by females plays a key role in their premating isolation. In addition, we summarized the potential isolation mechanisms of H. armigera and H. assulta.     

桃蛀螟,Dichocrocis punctiferalis Guenée,性信息素的微量组分的鉴定及田间试验(英文)

除主组分反-10-十六烯醛(E10-16:Ald)外,还鉴定了桃蛀螟.Dichocrocis punctiferalis Guenée.性信息素的两种微量组分:顺-10-十六烯醛(Z10-16:Ald)和十六醛(16:Ald)。采用单腺体提取、毛细管柱气相色谱分析的方法测定16:Ald,E10-16:Ald和Z-16:Ald的相对比例为13.0:80.4:6.6。田间试验表明,16:Ald和Z10-16:Ald单个组分诱不到雄蛾.引诱力强的是三组分诱芯(16:Ald:E-10:Ald:Z-Ald为16:100:8)和两组分的诱芯(E-10:Ald:Z-10:Ald为100:8)。     

Molecular characterization of two acetylcholinesterase genes from the oriental tobacco budworm, Helicoverpa assulta (Guenée)

Acetylcholinesterase (AChE) has been known to be the target of organophosphorous and carbamate insecticides. Only a single AChE, however, existed in insects and was involved in insecticide resistance, recently another AChE is reported in mosquitoes and aphids. We have cloned cDNAs encoding two ace genes, designated as Ha-ace1 and Ha-ace2 by a combined degenerate PCR and RACE strategy from adult heads of the oriental tobacco budworm, Helicoverpa assulta. The Ha-ace1 and Ha-ace2 genes encode 664 and 647 amino acids, respectively and have conserved motifs including a catalytic triad, a choline-binding site and an acyl pocket. Both Ha-AChEs were determined to be secretory proteins based on the existence of a signal peptide. The Ha-ace1 gene, the first reported ace1 in lepidopterans, belongs to the ace1 subfamily whereas the Ha-ace2 gene showed high similarity to those in the ace2 subfamily. Phylogenetic analysis showed that the Ha-ace1 gene was completely diverged from the Ha-ace2, suggesting that the Ha-ace genes are duplicated. Quantitative real time-PCR revealed that expression level of the Ha-ace1 gene was much higher than that of the Ha-ace2 in all body parts examined. The biochemical properties of purified proteins by affinity chromatography showed substrate specificity for acetylthiocholine iodide, and inhibitor specificity for BW284C51 and eserine and their peptide sequences partially identified by a MALDI-TOF mass spectrometer demonstrated that two Ha-AChEs were expressed in vivo.     

Genetic basis of sex pheromone blend difference between Helicoverpa armigera (Hübner) and Helicoverpa assulta (Guenée) (Lepidoptera: Noctuidae)

The two closely related moth species, Helicoverpa armigera and H. assulta, are sympatric in China. Both species use a mixture of (Z)-11-hexadecenal (Z11-16:Ald) and (Z)-9-hexadecenal (Z9-16:Ald) as their sex pheromones but in widely different ratios. Hybridization and backcrossing experiments between H. armigera and H. assulta were conducted and sex pheromone compositions of the parent species, their F(1) hybrids and backcrosses were compared to study the genetic basis of the production of their sex pheromone blend composition. Results show that the difference in sex pheromone blend ratios of these Helicoverpa species is mainly controlled by an autosomal locus with two alleles, with the allele from H. armigera being almost completely dominant over that derived from H. assulta.     

Tarsal taste neurons of Helicoverpa assulta (Guenée) respond to sugars and amino acids, suggesting a role in feeding and oviposition

Helicoverpa assulta and Helicoverpa armigera are sibling species with different host-plant ranges. We have previously reported electrophysiological and behavioral responses of H.armigera to sugars and amino acids. Here we describe a parallel study performed on H. assulta and compare the results obtained with the two species. In females, fourteen gustatory chemosensilla, identified on one ventrolateral side of the fifth tarsomere were stimulated with sucrose, glucose, fructose, maltose, myo-inositol, and the twenty common amino acids, using the tip-recording technique. The taste receptor neurons in eight chemosensilla were identified sensitive to the sugars, myo-inositol, Lys, Glu, Arg, Trp, and Ser which all induced proboscis extension reflex (PER) when tarsi were stimulated. There was a positive correlation between electrophysiological activities and PER responses triggered by sucrose. No stimulatory effect on oviposition was observed with sugar or amino acid mixtures. In males, three chemosensilla showed responses to the four sugars, but generally weaker than in females. The major difference of the two species was the variety of amino acids triggering electrophysiological responses. The stimulatory effect of sugars and amino acids on H.assulta was also generally weaker than that on H. armigera.     

Toxicity of Insecticides and Metabolism of Deltamethrin in Helicoverpa assulta Guenéee and Spodoptera litura Fabricius

This experiment was carried out to evaluate the effects of synergists on toxicity of deltamethrin and to investigate the pharmacokinetics of deltamethrin in Helicoverpa assulta Guenéee and Spodoptera litura Fabricius. Susceptibilities of H. assulta and Haman-collected S. litura to 7 insecticides revealed different responses between the 2 species. The different susceptibility of the 2 species to deltamethrin was correlated with the differences in the penetration and metabolism. Larvae of H. assulta pretreated with synergists (piperonyl butoxide (PB), S-benzyl-O, O-diisopropyl phosphorothioate (IBP), and diethyl maleate (DM) were more sensitive to deltamethrin, with the highest synergism ratio (SR = 6.8) being observed with PB. Significant differences in synergism among synergists were not observed. For S. litura, the highest SR(=8.8) was observed with PB. At all time periods, the penetration of ¹⁴C-deltamethrin was relatively faster to S. litura than to H. assulta. Time (hrs) required for 20% (t₂₀) of the applied doses to be excreted from treated S. litura was 1.5-fold faster than that of H. assulta. Higher synergism and longer retention in larval body of S. litura by the addition of PB suggest that the mixed function oxidase be a major factor in detoxification of deltamethrin. The combined use of PB with deltamethrin, and possibly other pyrethroids, might indicate a potential for controlling field populations resistant to deltamethrin and other pyrethroids.     

Oviposition model of Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae)

The longevity and fecundity of Cnaphalocrocis medinalis were investigated at temperatures of 15.0, 17.5, 20.0, 22.5, 25.0, 27.5, 30.0, 32.5, and 35.0 °C. Adult longevity and fecundity were significantly influenced by temperature. Longevity decreased with increasing temperature: it was highest at 15.0 °C (23.6 ± 3.51 days) and lowest at 35.0 °C (6.4 ± 0.48 days). Fecundity was highest at 25.0 °C (170.5 ± 45.54 eggs) and lowest at 17.5 °C (11.0 ± 3.68 eggs). The oviposition period was longest at 20.0 °C (8.0 ± 1.09 days) and shortest at 35.0 °C (2.3 ± 0.48 days). The oviposition model presented in this study consisted of two reproductive components (total fecundity and age-specific cumulative oviposition rate) and a survival component (age-specific survival rate). The relationship between adult developmental rate and temperature was described by the Lactin 2 model (r² = 0.98, p < 0.0001). The age-specific survival rate was well explained by a sigmoid function (r² = 0.97, p < 0.00001). The age-specific cumulative oviposition rate was best described by the three-parameter Weibull function (r² = 0.99, p < 0.00001). Temperature-dependent fecundity was estimated using the Briere-2 model (r² = 0.94, p < 0.007). Daily egg production of C. medinalis in relation to adult age and temperature was estimated.     

Biological aspects of Autoplusia egena (Guenée) (Lepidoptera: Noctuidae, Plusiinae)

Autoplusia egena (Guenée) is a moth distributed throughout the Western hemisphere. The larvae have already been found feeding on several different plant families, including important crops such soybeans and beans. To contribute to the knowledge of its biology in laboratory conditions, and considering the duration and the morphometry of each development stage, a laboratorial rearing was accomplished at 25 +/- 1 degrees C, 70 +/- 10% RH and 14h photophase. The larvae were fed with black bean leaves and the adults were fed with a honey solution at 10%. The results, expressed by the mean (+/- SE), for the periods of each stage were: egg 3.0 +/- 0.00 d; larva 15.7 +/- 1.25 d; pre-pupa 1.9 +/- 0.05 d; pupa 8.8 +/- 0.09 d and adult: longevity 12.1 +/- 0.95 d, pre-oviposition 5.4 +/- 0.50 d, oviposition 6.3 +/- 1.10 d and post-oviposition 1.4 +/- 0.87 d. The larvae went through five instars, for which the mean width of the cephalic capsules were 0.302 +/- 0.001 mm; 0.500 +/- 0.003 mm; 0.854 +/- 0.008 mm; 1.424 +/- 0.011 mm and 2.744 +/- 0.053 mm. The average length, width, and weight of the pupae were 16.965 +/- 0.003 mm, 4.674 +/- 0.040 mm and 0.217 +/- 0.003 g, respectively.     

Last instar larva and pupa of Melipotis cellaris (Guenée) (Lepidoptera: Noctuidae)

The last instar larva and pupa of Melipotis cellaris (Guenée) are described and illustrated, based on specimens collected in northern Chile, associated with Acacia macracantha (Fabaceae).     

SEX PHEROMONE COMPONENTS OF THE OREIENTAL TOBACCO BUDWORM, HELICOVERPA ASSULTA GUENÉE: IDENTIFICATION AND FIELD TRIALS

Abstract  The sex pheromone gland extracts of the Oriental tobacco budworm, Helicover assulta Guenée, collected from North China in Beijing area, were analyzed by capillary gas chromatograph(GC) and 6 components from the extracts were identified by capillary GC—MS as hexadecanal (16:Ald), (Z)9-hexadecenal (Z9–16:Ald), (Z)-11-hexadecenal (Z11–16:Ald), (Z)-9-hexadecen-1-ol (Z9–16:OH), Z11-hexadecen-1-ol (Z11–16:OH), Z-9-hexadecenylacetate (Z9–16:OAc) at a ratio of 10. 9: 58. 7: 3. 9: 14. 7: 1.1: 10. 7. Field studies indicated that an optimum blend of Z9–16:Ald and Z11–16:Ald was 100: 7. Addition of 16: Ald or Z9–16:Ac to the two aldehyde blend showed no significant effect on attractiveness. However presence of Z9–16:OH in the blends significantly reduced male captures.     

IDENTIFICATION OF MINOR COMPONENTS OF THE SEX PHEROMONE OF YELLOW PEACH MOTH DICHOROCIS PUNCTIFEEALIS GUENÉE AND FIELD TRIALS

Abstract  Along with the major component, (E1–10–hexadecenal (E10–16: Al,), two minor components, (Z)-10-hexadecenal(Z10-l6:Aid) and hexadecanal (16: Ald) were identified as components of the sex pheromone of Dichocrocis punctiferalis Guenee. Analysis of single sex pheromone gland extracts by capillary gas chromatography indicated that the relative ratio of 16:Ald, E10–16:Ald_t and 210–16:Ald was equal to 13. 0:80. 4:6. 6 respectively. Field trails indicated that 210–16: Ald and 16: Aid alone caught no males. The most attractive was a blend containing 16: Ald, E10–16:Ald, and 210–16: Ald at a ratio of 16:100:8, and a two-compound blend of E10–16:Ald and 210–16:Ald at a ratio of 100:8.     

槐小卷蛾性信息素活性成份的鉴定和林间试验(英文)

通过气相色谱（GC）、气相色谱──质谱（GC─MS）分析和微量化学反应,槐小卷蛾性信息素的一个活性成分被鉴定为（反,反）－8,10－十二碳双烯乙酸酯（E8,E10－12∶AC）。林间试验结果表明合成的E8,E10－12∶Ac对槐小卷蛾雄蛾有强烈引诱作用。     

棉铃虫性外激素成分的化学分析和田间试验

利用毛细柱的气相色谱和质谱对棉铃虫（鳞翅目：夜蛾科）雌蛾腺体提取物的分析,鉴定出了他和十六碳醛、顺－9－十六碳烯醛、顺－11－十六碳烯醛、饱和十六碳醇和顺－11－十六碳烯醇,其相对比例为6．1：4．5：100：3．5：8．8。在山东、山西省的田间试验中,2mg的顺－11－十六碳烯醛和顺－9－十六碳烯醛（97：3）置橡胶塞上能有效地引诱棉铃虫雄蛾。增加4％－7％他和十六碳醛到二元混合物中诱蛾量超过二元混合物。增加1％顺－11－十六碳烯醇到二元或三元混合物中减少诱蛾量,当增加5％顺－11－十六碳醇时诱蛾量大量减少。     

SEX PHEROMONE COMPONENTS OF HELICOVERPA ARMIGERA:CHEMICAL ANALYSIS AND FIELD TESTS*

Abstract Gas chromatographic and mass spectral analyses were conducted on the pheromone gland extracts of female moth of Helicoverpa armigera (Lepidoptera:Noctuidae). Saturated aldehyde (16:Ald), (Z)-9-hexadecenal (Z-9–16:Ald), (Z)-11-hexadecenal (Z-11–16:Ald), hexade-canol (16:OH) and (Z)-11-hexadecenol (2–11–16:OH) were found from gland extracts in the ratio of 6.1:4. 5 :100:3. 5 :8.8. In field tests of Shandong and Shanxi Provinces, 2 mg blends of Z -11–16:Ald and Z-9–16:Ald (97:3) applied on a rubber dispenser effectively attracted H. armigera males. The addition of 4%-7% 16 :Ald to the binary mixture caused increase over that of the binary mixture. The addition of 1%Z-11–16:OH to binary or trinary mixture may reduce catches, while addition of 5% Z-11–16:OH reduced catches singnificantly.     

SEX PHEROMONE OF THE FEMALE MOTHS CYDIA TRASIAS MEYRICK: IDENTIFICATION OF AN ACTIVE COMPONENT AND FIELD TRIALS*

Abstract An active component of the female sex pheromone of Chinese locust moth, Cydia Trash Meyrick, was identified as (E, E)-8, 10-dodecadienyl acetate (E8, E10–12:Ac) by GC, GC—MS analyses and microchemical reactions. The results of field trials showed that synthetic E8, E10—-12: Ac was very attractive to the male moths.     

棉铃虫Helicverpa armigera对性外激素和植物气味物质的嗅觉反应(英文)

本文用EAG技术研究棉铃虫对性外激素和植物气味物质的嗅觉反应。供试的气味物质有棉铃虫性外激素的二种主要组分和36种与棉铃虫寄主植物有关的植物气味物质。试验结果表明：1）只有棉铃虫雄蛾对性外激素组分产生反应,二种性外激素的组分中,Z-11-16：AL能引起较强的EAG反应。2）对植物气味物质,雌雄棉铃虫之间的嗅觉反应没有明显的差异。棉铃虫对性外激素和植物气味组分的嗅觉感受过程是一个有选择性的感受过程：不同种类的气味物质能引起不同的EAG反应。只有棉铃虫雄蛾才对性外激素组分起反应,在二种性外激素组分中：主要组分：Z-11-16：AL引起的EAG反应最高,高于大多数植物气味物质。次要组分Z-9-16：AL引起的EAG反应很弱。雌、雄棉铃虫对植物气味组分的嗅觉反应的选择性表现出一致的规律：对苯甲醛和绿叶气味物质的反应最高。单萜类中的萜烯衍生物（萜类醇、醛、酯等）的触角电位反应次之。棉铃虫对大多数的供试化合物的EAG反应都很小。最后,作者讨论了性外激素和植物气味物质对棉铃虫行为的作用。     

Electroantennogram, wind tunnel and field responses of male Mediterranean corn borer, Sesamia nonagrioides, to several blends of its sex pheromone components

The electrophysiological and behavioural responses of male Sesamia nonagrioides Lefèbvre (Lepidoptera: Noctuidae) to several synthetic blends of its sex pheromone components were investigated. Electroantennogram (EAG) recordings showed the greatest response to a 77:8:10:5 blend of the four compounds found in the female glands: (Z)-11-hexadecen-1-yl acetate, (Z)-11-hexadecen-1-ol, (Z)-11-hexadecenal and dodecyl acetate. A logistic equation was fitted to the dose-response data and differences in relative EAG responses were analysed by deriving five parameters of this equation. Flight responses of males were also evaluated in a wind tunnel where the proposed blend (77:8:10:5) also elicited the best response. Field tests confirmed the laboratory findings as the 77:8:10:5 blend captured more S. nonagrioides males than other pheromone mixtures and showed more selectivity for male S. nonagrioides over other noctuid species, Discestra trifolii Rottenberg and Lacanobia oleracea L., but not for Mythimna unipuncta Haworth, a species with a sex pheromone composition almost identical to that of S. nonagrioides.     

OLFACTORY RESPONSES OF COTTON BOLLWORM,HELICOVERPA ARMIGERA TO SEX PHEROMONE AND PLANT VOLATILE COMPONENTS*

Abstract Electroantennograms (EAGs) were recorded from unmated, laboratory-reared male and female Helicover pa armigera (Lepidoptera:Noctuidae) adults to two sex pheromone components and a range of plant volatile components, some of which are known volatiles from leaves and fruits. The female-produced sex pheromone was not detected by other female moths. The sex pheromone components to which male moths responded previously show to possess biological activity. As for plant volatile components, a large degree of EAG response uniformity between male and female moth was observed. The greatest EAG responses of all plant volatiles tested were elicited by monoenic C-6 alcohol and aldehyde. They are constituents of the “general green-leaf odor” that emanates from most plants. The potential adaptive benefit of selective perception to sex pheromone and green-leaf volatile components is discussed.