Moth sex pheromones affect interspecific competition among sympatric species and possibly population distribution by modulating pre-mating behavior

Premating behaviors mediated by pheromones play pivotal roles in animal mating choices. In natural populations of the striped stem borer Chilo suppressalis and the rice leaf roller Cnaphalocrocis medinalis in the rice field habitat, we discovered that Z11-16:Ald, a major component of the C. suppressalis pheromone, modulated the premating behavior of C. medinalis. Z11-16:Ald evoked a strong olfactory response in male antennae and strongly inhibited the sex pheromone trapping of male C. medinalis in the field. The functions of three C. medinalis sex pheromone receptor genes (CmedPR1–3) were verified through heterologous expression in Xenopus oocytes. CmedPR1 responded to Z11-18:OH and Z11-18:Ald, as well as the interspecific pheromone compound Z11-16:Ac of sympatric species; CmedPR2 responded to Z13-18:OH and Z13-18:Ald, as well as the sex pheromone compounds Z11-16:Ald and Z9-16:Ald of sympatric species; and CmedPR3 responded to Z11-18:OH and Z13-18:OH, as well as the interspecific pheromones Z11-16:OH, Z9-16:Ald, Z11-16:Ac, and Z11-16:Ald of sympatric species. Thus, CmedPR2 and CmedPR3 share the ligand Z11-16:Ald, which is not a component of the C. medinalis sex pheromone. Therefore, the sex pheromones of interspecific species affected the input of neural signals by stimulating the sex pheromone receptors on the antennae of male C. medinalis moths, thereby inhibiting the olfactory responses of the male moths to the sex pheromones. Our results demonstrate chemical communication among sympatric species in the rice field habitat, the recognition of intra- and interspecific sex pheromones by olfactory receptors, and how insect premating behaviors are modulated to possibly affect resource partitioning.     

Crystallographic Observation of pH-Induced Conformational Changes in the Amyelois transitella Pheromone-Binding Protein AtraPBP1

The navel orangeworm, Amyelois transitella is a major agricultural pest causing large losses in a variety of tree crops. Control of this insect pest may be achieved by interfering with olfactory pathways to block detection of female-produced sex pheromones and consequently, disrupt mating. The first component of this pathway is the pheromone-binding protein AtraPBP1, which recognizes the pheromone and presents it to the odorant receptor housed in a sensory neuron of the male antennae. Release of the ligand depends on a pH-induced conformational change associated with the acidity of the membrane surface. To characterize this conformational change and to understand how pheromones bind, we have determined the high resolution crystal structures of AtraPBP1 in complex with two main constituents of the sex pheromone, i.e., (11Z,13Z)-hexadecadienal and (11Z,13Z)-hexadecadienol. Comparison with the structure of the unliganded form demonstrates a large ∼90° movement of the C-terminal helix which is observed in other pheromone- or odorant-binding proteins accompanied by an unpredicted 37° displacement of the N-terminal helix. Molecular dynamic trajectories suggest that the conformational change of the α1 helix facilitates the movement of the C-terminal helix.     

Identification and Characterization of an Antennae-Specific Aldehyde Oxidase from the Navel Orangeworm

Antennae-specific odorant-degrading enzymes (ODEs) are postulated to inactivate odorant molecules after they convey their signal. Different classes of insect ODEs are specific to esters, alcohols, and aldehydes – the major functional groups of female-produced, hydrophobic sex pheromones from moth species. Esterases that rapidly inactive acetate and other esters have been well-studied, but less is known about aldehyde oxidases (AOXs). Here we report cloning of an aldehyde oxidase, AtraAOX2, from the antennae of the navel orangeworm (NOW), Amyelois transitella, and the first activity characterization of a recombinant insect AOX. AtraAOX2 gene spans 3,813 bp and encodes a protein with 1,270 amino acid residues. AtraAOX2 cDNA was expressed in baculovirus-infected insect Sf21 cells as a ≈280 kDa homodimer with 140 kDa subunits. Recombinant AtraAOX2 degraded Z11Z13–16Ald and plant volatile aldehydes as substrates. However, as expected for aldehyde oxidases, recombinant AtraAOX2 did not show specificity for Z11Z13–16Ald, the main constituent of the sex pheromone, but showed high activity for plant volatile aldehydes. Our data suggest AtraAOX2 might be involved in degradation of a diversity of aldehydes including sex pheromones, plant-derived semiochemicals, and chemical cues for oviposition sites. Additionally, AtraAOX2 could protect the insect''s olfactory system from xenobiotics, including pesticides that might reach the sensillar lymph surrounding the olfactory receptor neurons.     

Odorant Receptors of the New Zealand Endemic Leafroller Moth Species Planotortrix octo and P. excessana

Moths use their sense of smell to find food sources, mating partners and oviposition sites. For this they possess a family of odorant receptors (ORs). Some ORs are used by both sexes whereas others have sex-specific roles. For example, male moths possess ORs specifically tuned to sex pheromones produced by conspecific females. Here we identify sets of ORs from the antennae of New Zealand endemic leafroller moths Planotortrix octo (48 ORs) and P. excessana (47 ORs) using an RNA-Seq approach. Two orthologous ORs show male-biased expression in the adult antennae of both species (OR7 and OR30) and one other OR in each species was female-biased in its expression (PoctOR25, PexcOR14) by qPCR. PAML analysis conducted on male-biased ORs indicated positive selection acting on the male-biased OR7. The fact that OR7 is likely under positive selection, that it is male-biased in its expression and that its orthologue in C. obliquana, CoblOR7, responds to sex pheromone components also utilised by Planotortrix species, suggests that this receptor may also be important in sex pheromone reception in Planotortrix species.     

Functional Specificity of Sex Pheromone Receptors in the Cotton Bollworm Helicoverpa armigera

Male moths can accurately perceive the sex pheromone emitted from conspecific females by their highly accurate and specific olfactory sensory system. Pheromone receptors are of special importance in moth pheromone reception because of their central role in chemosensory signal transduction processes that occur in olfactory receptor neurons in the male antennae. There are a number of pheromone receptor genes have been cloned, however, only a few have been functionally characterized. Here we cloned six full-length pheromone receptor genes from Helicoverpa armigera male antennae. Real-time PCR showing all genes exhibited male-biased expression in adult antennae. Functional analyses of the six pheromone receptor genes were then conducted in the heterologous expression system of Xenopus oocytes. HarmOR13 was found to be a specific receptor for the major sex pheromone component Z11-16:Ald. HarmOR6 was equally tuned to both of Z9-16: Ald and Z9-14: Ald. HarmOR16 was sensitively tuned to Z11-16: OH. HarmOR11, HarmOR14 and HarmOR15 failed to respond to the tested candidate pheromone compounds. Our experiments elucidated the functions of some pheromone receptor genes of H. armigera. These advances may provide remarkable evidence for intraspecific mating choice and speciation extension in moths at molecular level.     

A single sex pheromone receptor determines chemical response specificity of sexual behavior in the silkmoth Bombyx mori

In insects and other animals, intraspecific communication between individuals of the opposite sex is mediated in part by chemical signals called sex pheromones. In most moth species, male moths rely heavily on species-specific sex pheromones emitted by female moths to identify and orient towards an appropriate mating partner among a large number of sympatric insect species. The silkmoth, Bombyx mori, utilizes the simplest possible pheromone system, in which a single pheromone component, (E, Z)-10,12-hexadecadienol (bombykol), is sufficient to elicit full sexual behavior. We have previously shown that the sex pheromone receptor BmOR1 mediates specific detection of bombykol in the antennae of male silkmoths. However, it is unclear whether the sex pheromone receptor is the minimally sufficient determination factor that triggers initiation of orientation behavior towards a potential mate. Using transgenic silkmoths expressing the sex pheromone receptor PxOR1 of the diamondback moth Plutella xylostella in BmOR1-expressing neurons, we show that the selectivity of the sex pheromone receptor determines the chemical response specificity of sexual behavior in the silkmoth. Bombykol receptor neurons expressing PxOR1 responded to its specific ligand, (Z)-11-hexadecenal (Z11-16:Ald), in a dose-dependent manner. Male moths expressing PxOR1 exhibited typical pheromone orientation behavior and copulation attempts in response to Z11-16:Ald and to females of P. xylostella. Transformation of the bombykol receptor neurons had no effect on their projections in the antennal lobe. These results indicate that activation of bombykol receptor neurons alone is sufficient to trigger full sexual behavior. Thus, a single gene defines behavioral selectivity in sex pheromone communication in the silkmoth. Our findings show that a single molecular determinant can not only function as a modulator of behavior but also as an all-or-nothing initiator of a complex species-specific behavioral sequence.     

黄杨绢野螟雌蛾性信息素的鉴定及诱蛾活性

【目的】研究旨在深入探讨中国黄杨绢野Diaphania perspectalis 的雌蛾性信息素组成及诱蛾活性。【方法】利用气质联用仪（GC-MS）对黄杨绢野螟正常型性成熟雌蛾的性腺体提取物和合成标样比较分析,并用反-11-十六碳烯醛(E11-16:Ald) 、顺-11-十六碳烯醛（Z-11-16:Ald）、顺-9-十六碳烯醛（Z-9-16:Ald)、顺-11-十六碳烯醇（Z-11-16:OH)等物质进行触角的电生理测定,最后开展田间诱集比较试验以筛选出最佳性信息素混合物。【结果】Z-11-16:Ald为中国黄杨绢野螟正常型性信息素主要组分,E-11-16:Ald的含量极低,Z-11-16:OH未检测到。正常型雄性黄杨绢野螟触角对Z-11-16:Ald, E-11-16:Ald, Z-9-16:Ald和Z-11-16:OH产生强烈的EAG反应,并随着浓度的提高而显著增加;而对Z-11-16:Ac和E-11-16:Ac的嗅觉反应较弱,低于对植物绿叶气味顺3-己烯乙酸酯（Z-3-6:Ac）的反应。单一Z-1-16:Ald对正常型雄性黄杨绢野螟具有强烈的诱集效果,加入E-11-16:Ald有一定的增效作用,但在统计上则不显著。单一Z-11-16:Ald组分对黑化型雄性黄杨绢野螟无引诱活性,必需加入一定比例的E-11-16:Ald才显示诱蛾活性。Z-11-16:Ald:E-11-16:Ald的比例为250 μg:250 μg时诱集到的黑化型雄性黄杨绢野螟数量最多,而Z-11-16:Ald:E-11-16:Ald的比例为429 μg:71 μg时则诱集到的正常型雄性黄杨绢野螟数量最多。同时,单一Z-11-16:Ald也可引诱大量雄性粘虫Mythimna separata,但E-11-16:Ald抑制其活性。【结论】中国黄杨绢野螟的性信息素主成分是Z-11-16:Ald,单一组分即可在田间强烈引诱雄蛾,E-11-16:Ald的功能只起到微弱的增效作用,但也可能起种的专一性的作用。正常型与黑化型黄杨绢野螟对性信息素的嗅觉反应存在差异,黑化型黄杨绢野螟的性信息素接近日本种,即性信息素组成为Z-11-16:Ald和E-11-16:Ald 的混合物,其比例为1:1,且E-11-16:Ald为必需。     

温度对二化螟性信息素通讯的影响

环境因素影响昆虫两性间的化学通讯,也影响性信息素技术的田间防治效果.本文探讨了温度对二化螟雌蛾性信息素产生以及雄蛾对性信息素触角电位反应的影响,以期为田间二化螟的性信息素防治提供指导.在二化螟蛹期和成虫期进行不同温度处理(15、20、25、30和35 ℃),然后利用气相色谱仪(GC)分析雌蛾性腺内各性信息素组分的含量及比例,同时利用触角电位仪(EAG)测定雄蛾对性信息素组分的电生理反应.结果表明: 25 ℃处理中雌蛾性腺内3个性信息素组分(Z9-16:Ald、Z11-16:Ald和Z13-18:Ald)的含量均显著高于其他温度处理(15、20和30 ℃),且25 ℃处理中Z13-18:Ald的相对比例也显著低于其他温度处理.就雄蛾对性信息素的敏感性而言,对3种性信息素单一组分及特定比例混合物的EAG反应在15～25 ℃间没有显著差异,但在25～35 ℃间(Z13-18:Ald在30～35 ℃间)随温度升高呈下降趋势,且30 ℃较25 ℃显著降低,35 ℃较30 ℃又显著降低.综合分析认为,二化螟性信息素通讯的适宜温度为20～25 ℃,温度过高或过低均不利于二化螟两性间的正常化学通讯.研究结果为二化螟性信息素防治技术的合理应用及极端温度条件下害虫种群发生的预测预报,提供了重要参考.     

Female sex pheromone components of Helicoverpa gelotopoeon: first heliothine pheromone without (Z)-11-hexadecenal

Helicoverpa gelotopoeon Dyar is a very important pest of economic importance on cotton in Argentina. Analysis of female pheromone gland extracts prepared from 1‐ to 2‐day‐old virgin female moths demonstrated the presence of a 1 : 0.84 blend of hexadecanal (16:Ald) and (Z)‐9‐hexadecenal (Z9‐16:Ald), with trace quantities of tetradecanal in some samples, 2.4% of 16:Ald. The average quantity of Z9‐16:Ald extracted per female was estimated to be 33 ng, with a range of 18.9–46.4 ng per female when collected 2–3 h into the scotophase. In field trials conducted in both cotton and tomato crops in Santiago del Estero, Argentina 1 : 1 blends of 16:Ald and Z9‐16:Ald caught significantly more male H. gelotopoeon than Z9‐16:Ald alone, although there was no significant difference between blends containing between a 0.2 : 1 and 2 : 1 ratio of 16:Ald and Z9‐16:Ald. There was no analytical evidence for the presence of (Z)‐11‐hexadecenal (Z11‐16:Ald) in pheromone gland extracts, although this compound has been identified in all female sex pheromones of Heliothinae to date. In field trials, the addition of Z11‐16:Ald at the 1% level to either a 1 : 1 blend of 16:Ald and Z9‐16:Ald or Z9‐16:Ald alone significantly reduced the catch of male H. gelotopoeon. Sympatric Heliothis virescens were not caught in any of the blends tested for H. gelotopoeon, but were caught in low numbers in traps baited with a 4 : 100 blend of (Z)‐9‐tetradecenal and (Z)‐11‐hexadecenal.     

Sex-linked pheromone receptor genes of the European corn borer, Ostrinia nubilalis, are in tandem arrays

Background

Tuning of the olfactory system of male moths to conspecific female sex pheromones is crucial for correct species recognition; however, little is known about the genetic changes that drive speciation in this system. Moths of the genus Ostrinia are good models to elucidate this question, since significant differences in pheromone blends are observed within and among species. Odorant receptors (ORs) play a critical role in recognition of female sex pheromones; eight types of OR genes expressed in male antennae were previously reported in Ostrinia moths.

Methodology/Principal Findings

We screened an O. nubilalis bacterial artificial chromosome (BAC) library by PCR, and constructed three contigs from isolated clones containing the reported OR genes. Fluorescence in situ hybridization (FISH) analysis using these clones as probes demonstrated that the largest contig, which contained eight OR genes, was located on the Z chromosome; two others harboring two and one OR genes were found on two autosomes. Sequence determination of BAC clones revealed the Z-linked OR genes were closely related and tandemly arrayed; moreover, four of them shared 181-bp direct repeats spanning exon 7 and intron 7.

Conclusions/Significance

This is the first report of tandemly arrayed sex pheromone receptor genes in Lepidoptera. The localization of an OR gene cluster on the Z chromosome agrees with previous findings for a Z-linked locus responsible for O. nubilalis male behavioral response to sex pheromone. The 181-bp direct repeats might enhance gene duplications by unequal crossovers. An autosomal locus responsible for male response to sex pheromone in Heliothis virescens and H. subflexa was recently reported to contain at least four OR genes. Taken together, these findings support the hypothesis that generation of additional copies of OR genes can increase the potential for male moths to acquire altered specificity for pheromone components, and accordingly, facilitate differentiation of sex pheromones.     

Broadly and narrowly tuned odorant receptors are involved in female sex pheromone reception in Ostrinia moths

Mate-finding communication in many moths is mediated by sex pheromones produced by females. Since the differentiation of sex pheromones is often associated with speciation, it is intriguing to elucidate how the changes in sex pheromones are tracked by the pheromone recognition system of the males. Moths of the genus Ostrinia, which show distinct differentiation in female sex pheromones, are good models to study this. The present study was initiated with the aim of identifying ORs from Ostrinia scapulalis that respond to its own pheromone components, (E)-11- and (Z)-11-tetradecenyl acetates. We isolated six OR gene candidates (OscaOR3–8) from O. scapulalis. The same set of genes homologous to OscaOR3–8 were conserved in all (eight) Ostrinia species examined in addition to the previously reported OscaOR1 (tuned to (E)-11-tetradecenol) and the Or83b homologue OscaOR2. OscaOR3 not only responded to (E)-11- and (Z)-11-tetradecenyl acetates, but also to the pheromone components of the congeners, (Z)-9-, (E)-12-, and (Z)-12-tetradecenyl acetates. OscaOR4 responded with a relatively high specificity to (E)-11-tetradecenyl acetate. While OscaOR5 responded only marginally to a few pheromone components, OscaOR6–8 did not respond to any of the compounds tested. A few conserved ORs, including a unique one with very broad responsiveness, appear to be involved in the sex pheromone reception in O. scapulalis. The findings of the present study are discussed with reference to knowledge on electrophysiological response profiles of olfactory receptor neurons in Ostrinia moths.     

Moths behaving like butterflies. Evolutionary loss of long range attractant pheromones in castniid moths: a Paysandisia archon model

Background

In the course of evolution butterflies and moths developed two different reproductive behaviors. Whereas butterflies rely on visual stimuli for mate location, moths use the ‘female calling plus male seduction’ system, in which females release long-range sex pheromones to attract conspecific males. There are few exceptions from this pattern but in all cases known female moths possess sex pheromone glands which apparently have been lost in female butterflies. In the day-flying moth family Castniidae (“butterfly-moths”), which includes some important crop pests, no pheromones have been found so far.

Methodology/Principal Findings

Using a multidisciplinary approach we described the steps involved in the courtship of P. archon, showing that visual cues are the only ones used for mate location; showed that the morphology and fine structure of the antennae of this moth are strikingly similar to those of butterflies, with male sensilla apparently not suited to detect female-released long range pheromones; showed that its females lack pheromone-producing glands, and identified three compounds as putative male sex pheromone (MSP) components of P. archon, released from the proximal halves of male forewings and hindwings.

Conclusions/Significance

This study provides evidence for the first time in Lepidoptera that females of a moth do not produce any pheromone to attract males, and that mate location is achieved only visually by patrolling males, which may release a pheromone at short distance, putatively a mixture of Z,E-farnesal, E,E-farnesal, and (E,Z)-2,13-octadecadienol. The outlined behavior, long thought to be unique to butterflies, is likely to be widespread in Castniidae implying a novel, unparalleled butterfly-like reproductive behavior in moths. This will also have practical implications in applied entomology since it signifies that the monitoring/control of castniid pests should not be based on the use of female-produced pheromones, as it is usually done in many moths.     

Olfactory Proteins Mediating Chemical Communication in the Navel Orangeworm Moth,Amyelois transitella

Background

The navel orangeworm, Amyelois transitella Walker (Lepidoptera: Pyralidae), is the most serious insect pest of almonds and pistachios in California for which environmentally friendly alternative methods of control — like pheromone-based approaches — are highly desirable. Some constituents of the sex pheromone are unstable and could be replaced with parapheromones, which may be designed on the basis of molecular interaction of pheromones and pheromone-detecting olfactory proteins.

Methodology

By analyzing extracts from olfactory and non-olfactory tissues, we identified putative olfactory proteins, obtained their N-terminal amino acid sequences by Edman degradation, and used degenerate primers to clone the corresponding cDNAs by SMART RACE. Additionally, we used degenerate primers based on conserved sequences of known proteins to fish out other candidate olfactory genes. We expressed the gene encoding a newly identified pheromone-binding protein, which was analyzed by circular dichroism, fluorescence, and nuclear magnetic resonance, and used in a binding assay to assess affinity to pheromone components.

Conclusion

We have cloned nine cDNAs encoding olfactory proteins from the navel orangeworm, including two pheromone-binding proteins, two general odorant-binding proteins, one chemosensory protein, one glutathione S-transferase, one antennal binding protein X, one sensory neuron membrane protein, and one odorant receptor. Of these, AtraPBP1 is highly enriched in male antennae. Fluorescence, CD and NMR studies suggest a dramatic pH-dependent conformational change, with high affinity to pheromone constituents at neutral pH and no binding at low pH.     

Sex pheromone components of the rice leaffolder,Cnaphalocrocis medinalis (Lepidoptera: Crambidae), in Indonesia

Field tests of three synthetic sex pheromone blends (Japanese blend: Z11–18:Ald (55 μg), Z13–18:Ald (500 μg), Z11–18:OH (120 μg) and Z13–18:OH (180 μg), Indian blend: Z11–16:Ac (50 μg) and Z13–18:Ac (500 μg) and Philippine blend: Z11–16:Ac (500 μg) and Z13–18:Ac (10 μg) based on geographic variations in sex pheromones) of the rice leaffolder moth, Cnaphalocrocis medinalis Guenée (Lepidoptera: Crambidae), were conducted at Yogyakarta (Java), and at Sempidi and Penatih (Bali), Indonesia. Only the Japanese blend attracted significant numbers of male C. medinalis, while neither the Indian nor the Philippine blend showed any attractiveness to the males. In the GC–MS analysis of a crude extract from pheromone glands of female C. medinalis collected at Sanur, Bali. Indonesia, Z11–18:Ald, Z13–18:Ald, Z11–18:OH and Z13–18:OH were detected at a ratio of 10:100:26:37, and the total amount was approximately 0.8 ng/female. Neither Z11–16:Ac nor Z13–18:Ac were detected. These results suggest that C. medinalis that respond to the Japanese blend are widely distributed from Eastern Asia through Southeast Asia.     

A male-specific odorant receptor conserved through the evolution of sex pheromones in Ostrinia moth species

In many moths, mate-finding communication is mediated by the female sex pheromones. Since differentiation of sex pheromones is often associated with speciation, it is intriguing to know how the changes in female sex pheromone have been tracked by the pheromone recognition system of the males. A male-specific odorant receptor was found to have been conserved through the evolution of sex pheromone communication systems in the genus Ostrinia (Lepidoptera: Crambidae). In an effort to characterize pheromone receptors of O. scapulalis, which uses a mixture of (E)-11- and (Z)-11-tetradecenyl acetates as a sex pheromone, we cloned a gene (OscaOR1) encoding a male-specific odorant receptor. In addition, we cloned a gene of the Or83b family (OscaOR2). Functional assays using Xenopus oocytes co-expressing OscaOR1 and OscaOR2 have shown that OscaOR1 is, unexpectedly, a receptor of (E)-11-tetradecenol (E11-14:OH), a single pheromone component of a congener O. latipennis. Subsequent studies on O. latipennis showed that this species indeed has a gene orthologous to OscaOR1 (OlatOR1), a functional assay of which confirmed it to be a gene encoding the receptor of E11-14:OH. Furthermore, investigations of six other Ostrinia species have revealed that all of them have a gene orthologous to OscaOR1, although none of these species, except O. ovalipennis, a species most closely related to O. latipennis, uses E11-14:OH as the pheromone component. The present findings suggest that the male-specific receptor of E11-14:OH was acquired before the divergence of the genus Ostrinia, and functionally retained through the evolution of this genus.     

The male sex pheromone of the butterfly Bicyclus anynana: towards an evolutionary analysis

Background

Female sex pheromones attracting mating partners over long distances are a major determinant of reproductive isolation and speciation in Lepidoptera. Males can also produce sex pheromones but their study, particularly in butterflies, has received little attention. A detailed comparison of sex pheromones in male butterflies with those of female moths would reveal patterns of conservation versus novelty in the associated behaviours, biosynthetic pathways, compounds, scent-releasing structures and receiving systems. Here we assess whether the African butterfly Bicyclus anynana, for which genetic, genomic, phylogenetic, ecological and ethological tools are available, represents a relevant model to contribute to such comparative studies.

Methodology/Principal Findings

Using a multidisciplinary approach, we determined the chemical composition of the male sex pheromone (MSP) in the African butterfly B. anynana, and demonstrated its behavioural activity. First, we identified three compounds forming the presumptive MSP, namely (Z)-9-tetradecenol (Z9-14:OH), hexadecanal (16:Ald ) and 6,10,14-trimethylpentadecan-2-ol (6,10,14-trime-15-2-ol), and produced by the male secondary sexual structures, the androconia. Second, we described the male courtship sequence and found that males with artificially reduced amounts of MSP have a reduced mating success in semi-field conditions. Finally, we could restore the mating success of these males by perfuming them with the synthetic MSP.

Conclusions/Significance

This study provides one of the first integrative analyses of a MSP in butterflies. The toolkit it has developed will enable the investigation of the type of information about male quality that is conveyed by the MSP in intraspecific communication. Interestingly, the chemical structure of B. anynana MSP is similar to some sex pheromones of female moths making a direct comparison of pheromone biosynthesis between male butterflies and female moths relevant to future research. Such a comparison will in turn contribute to understanding the evolution of sex pheromone production and reception in butterflies.     

棉铃虫成虫对性信息素的电生理和行为反应研究

通过EAG和风洞实验,研究了棉铃虫雌雄成虫对性信息素组分和诱芯(Z-11-16Ald∶Z-9-16Ald=97∶3)的电生理反应。其中棉铃虫雌、雄蛾对诱芯的平均EAG反应测定值分别为1.06mV和4.32mV,分别高出对照(无性信息素空白诱芯)0.67mV和0.366mV,差异均达到极显著水平(雌蛾：t＝25.020, P≤0.01;雄蛾：t＝44.269,P≤0.01);棉铃虫雌蛾对性信息素组分(Z-11-16-Ald和Z-9.16Ald)的EAG反应值随浓度增加而增加;雄蛾在被剪除触角后与雌蛾不能正常交配,而雌蛾在被剪除触角后仍有40%的交配率,比正常雌雄蛾的交配率(70%)有所下降;在风洞实验中,雄蛾没有顺风远离诱源的飞行行为,趋向诱源的比率为81.8%,与对照有显著差异。研究表明性信息素组分对棉铃虫的交配活动有明显的影响。