Climate-dependent dispersal rates in metapopulations of burnet moths

Predicted climate change implies warmer weather and a higher frequency of extreme weather situations. The consequences of the warm July in 2003 was investigated in contrast to the cold July in 2004 in southern Sweden with focus on the dispersal rate of two species of burnet moths (Zygaenidae). During an extensive mark-release-recapture program in metapopulations of burnet moths substantial differences in inter habitat patch dispersal rates were observed. For two species of Zygaena it was 2.14 and 2.18 times higher during the warm year. Measured patch dispersal rate significantly declined towards the edges of the large study-area, suggesting that individuals disperse outside the study-area. No significant differences in dispersal rates were found between the two species studied. The dispersal rates were similar for both females and males, and no density dependent effects on dispersal or effects of amount of nectar rich flowers were found. Dispersal events appeared as distinct movements, often reaching several kilometres. We conclude that dispersal depend on climatic conditions. Exceptionally warm years may be especially important for survival of certain species in metapopulation systems and this may be crucial for the survival of populations during scenarios of climate change.     

No evidence of quantitative signal honesty across species of aposematic burnet moths (Lepidoptera: Zygaenidae)

Many defended species use conspicuous visual warning signals to deter potential predators from attacking. Traditional theory holds that these signals should converge on similar forms, yet variation in visual traits and the levels of defensive chemicals is common, both within and between species. It is currently unclear how the strength of signals and potency of defences might be related: conflicting theories suggest that aposematic signals should be quantitatively honest, or, in contrast, that investment in one component should be prioritized over the other, while empirical tests have yielded contrasting results. Here, we advance this debate by examining the relationship between defensive chemicals and signal properties in a family of aposematic Lepidoptera, accounting for phylogenetic relationships and quantifying coloration from the perspective of relevant predators. We test for correlations between toxin levels and measures of wing colour across 14 species of day‐flying burnet and forester moths (Lepidoptera: Zygaenidae), protected by highly aversive cyanogenic glucosides, and find no clear evidence of quantitative signal honesty. Significant relationships between toxin levels and coloration vary between sexes and sampling years, and several trends run contrary to expectations for signal honesty. Although toxin concentration is positively correlated with increasing luminance contrast in forewing pattern in 1 year, higher toxin levels are also associated with paler and less chromatically salient markings, at least in females, in another year. Our study also serves to highlight important factors, including sex‐specific trends and seasonal variation, that should be accounted for in future work on signal honesty in aposematic species.     

Higher phylogeny of zygaenid moths (Insecta: Lepidoptera) inferred from nuclear and mitochondrial sequence data and the evolution of larval cuticular cavities for chemical defence

Zygaenid moths are capable of releasing hydrogen cyanide in their defense by enzymatic break-down of cyanoglucosides, but only larvae of chalcosiine and zygaenine moths store cyanogenic compounds in cuticular cavities and thus are able to discharge defense droplets, which effectively deter potential predators. A previously proposed phylogeny of Zygaenidae hypothesized a sister group relationship of chalcosiine and zygaenine moths because of their similar larval defense system. Not all chalcosiine taxa possess cuticular cavities, however, and a comparable defense mechanism has been reported in larvae of the zygaenoid family Heterogynidae. Considering sequence data of seven molecular loci, the present study estimates the posterior probability of phylogenetic hypotheses explaining the occurrence of larval cuticular cavities. The molecular data confirm the previous exclusion of Himantopteridae from Zygaenidae and suggest their close affinity to Somabrachyidae. The sequence data also corroborate the recently proposed exclusion of the Phaudinae from the Zygaenidae, because this subfamily is recovered in a reasonably well supported species cluster consisting of members of the families Lacturidae, Limacodidae, Himantopteridae, and Somabrachyidae. We consequently agree to raise Phaudinae to family rank. Within Zygaenidae, the subfamilies Callizygaeninae, Chalcosiinae, and Procridinae most likely constitute a monophyletic group, which is sister to the Zygaeninae. Our results imply that cuticular cavities were probably present in the larvae of the most recent common ancestor of Zygaenidae. Heterogynidae cannot be confirmed as sister taxon to this family, but appear at the very first split of the Zygaenoidea, although with poor support. The specific pattern of taxa in the molecular phylogeny showing larval cuticular cavities opens the possibility that these structures could have been already present in the most recent common ancestor of the Zygaenoidea.     

天牛性信息素、引诱植物和植物性引诱剂的研究与应用

由于目前所拥有的各种天牛防治方法都难以获得理想的防治效果,研发新型天牛控制技术势在必行。其中利用引诱剂是最具潜力的研究领域之一。对天牛的性信息素、引诱植物和植物性引诱剂3个方面的研究及应用作了综述。天牛雌、雄成虫均可释放性信息素进行两性间的通讯联系。天牛性信息素的分泌部位因天牛种类不同而存在着差异。雄、雌成虫触角上均有感受性信息素的感受器,但报道较多的是雄虫感受器。迄今已鉴定出13种天牛性信息素的化学结构。一般而言,天牛成虫的嗜食树种,对天牛具有较强的引诱作用,可作为诱饵树种使用。寄主植物的某些挥发性物质对天牛成虫也有独特的引诱效果。除此之外,对天牛性信息素、引诱植物和植物性引诱剂研究与应用中存在的困难也进行了讨论,并对它们的应用前景做了展望。     

蛾类性信息素生物合成途径及其调控

蛾类通过产生和识别物种特异性性信息素来引发后续交配行为,因此它在两性交配行为中至关重要.它们具有不同碳链长度、末端官能团、不同双键位置和构型等化学结构特征,本文详细讨论了不同蛾类性信息素的合成途径以及催化每一步反应的相关酶系,列举了15种夜蛾科不同亚科常见物种的性信息素组分及其比例,总结了产生特定比例性信息素的可能原因,查阅了夜蛾科不同物种已经鉴别的性信息素,并按照不同亚科、不同官能团和碳链长度对其进行分类,归纳了同一物种及其亲缘物种性信息素组分和比例的变异,总结了产生变异的分子机理,讨论了性信息素变异和物种进化的关系.最后以生物合成激活神经肽(PBAN)为主, 介绍了其调控途径和机制.本文旨在以不同的蛾类性信息素合成途径为线索,从共有合成途径出发深入了解其规律和共性,从特异合成途径出发探究物种间的进化和变异,展望未来的研究方向及其应用.     

Lepidopterous Sex Attractants with a Conjugated Diene System

Each of fifty-one conjugated dienes (alcohols, acetates and aldehydes) with a C₁₂, C₁₄ or C₁₆ straight chain was applied to a rubber cap in a sticky-type trap as a single-component lure. Some diene compounds were mixed with their functional derivatives or structurally related monoenes to make two-component lures. In field trials conducted from 1984 to 1986, the new attraction of male moths of nineteen species was observed. These species were classified into nine families as follow: Gracillariidae, Yponomeutidae, Oecophoridae, Cosmopterigidae, Tortricidae (Olethreuti- nae and Tortricinae), Pyralidae, Pterophoridae, Drepanidae and Geometridae. This result indicates that the conjugated dienes are one of the main groups of lepidopterous sex pheromones. Some interesting information concerned with the taxonomy of the attracted moths and with the characteristics of the chemical structures of their attractants was obtained.     

Molecular mechanisms underlying sex pheromone production in the silkmoth, Bombyx mori: characterization of the molecular components involved in bombykol biosynthesis

Many species of female moths produce sex pheromones to attract conspecific males. To date, sex pheromones from more than 570 moth species have been chemically identified. Most moth species utilize Type I pheromones that consist of straight-chain compounds 10-18 carbons in length with a functional group of a primary alcohol, aldehyde, or acetate ester and usually with several double bonds. In contrast, some moth species use unsaturated hydrocarbons or hydrocarbon epoxides, classified as Type II lepidopteran pheromones, as sex pheromones. Studies over the past three decades have demonstrated that female moths usually produce sex pheromones as multi-component blends where the ratio of the individual components is precisely controlled, thus making it possible to generate species-specific pheromone blends. As for the biosynthesis of Type I pheromones, it is well established that they are de novo synthesized in the pheromone gland (PG) through modifications of fatty acid biosynthetic pathways. However, as many of the molecular components within the PG cells (i.e., enzymes, proteins, and small regulatory molecules) have not been functionally characterized, the molecular mechanisms underlying sex pheromone production in PG cells remain poorly understood. To address this, we have recently characterized some of the molecules involved in the biosynthesis of the sex pheromone bombykol in the silkmoth, Bombyx mori. Characterization of these, and other, key molecules will facilitate our understanding of the precise mechanisms underlying lepidopteran sex pheromone production.     

植食性金龟子信息化学物质的研究

金龟子信息化学物质包括性信息素、聚集信息素和植物源引诱剂。目前已鉴定出的性信息素大多集中于丽金龟科和鳃金龟科,犀金龟科只鉴定出了几种聚集信息素,有关植物源引诱剂方面的研究则集中于丽金龟科和花金龟科。本文总结了金龟子信息化学物质的化学结构特点,并评述了金龟子化学通讯中独特的手性性信息素相互拮抗作用及性信息素生物合成的研究。     

A failed attempt to demonstrate pheromone communication in archaic moths of the genus Sabatinca Walker (Lepidoptera, Micropterigidae)

Data on pheromones of phylogenetically archaic moths are very scant, despite being needed to understand the life history evolution and phylogeny of the basal lineages of Lepidoptera. Two New Zealand micropterigid moths, Sabatinca (Palaeomicra) chalcophanes Meyr. and Sabatinca (s.str.) demissa Philp., were investigated for pheromone communication. Consistent negative results were demonstrated by (i) behavioural observations, (ii) exposure of blends containing active components of pheromones identified in caddis-flies and archaic moths, (iii) exposure of caged males and females in sticky traps, and (iv) detection of male and female antennal responses to both male and female extracts. Since no data indicated the presence of long-distance sex pheromones in Sabatinca , we concluded that these moths use visual clues to meet sexual partners. The secondary lack of pheromone communication in Micropterigidae suggests a high degree of ecological specialization in this plylogenetically most archaic moth family.     

金龟子化学通讯与信息化学物质

本文综述了金龟子的化学通讯与信息化学物质研究与应用的新进展,重点评述了丽金龟科和鳃金龟科性信息素的鉴定与化学结构。迄今,已有14种金龟子的性信息素被鉴定,还有一些金龟子的聚集信息素和两性引诱剂被报道。对金龟子性信息素、聚集信息素和引诱剂等信息化学物质的应用也作了概述。     

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.     

蛾类昆虫性信息素生物合成的研究进展

综述了各种不同化学结构类型的蛾类雌性信息素生物合成途径。此外还叙述了特定比例的性信息素成分在雌蛾体内产生的机理以及某些蛾类中信息素生物合成酶类与物种进化间的关系。     

Alkenyl sex pheromone analogs in the hemolymph of an arctiid Eilema japonica and several non-arctiid moths

The majority of moth species utilize compounds derived from de novo synthesized fatty acids as their sex pheromones (type I). In contrast, species belonging to two recently diverged moth families, Arctiidae and Geometridae, utilize alkenes and their epoxides, which are derived from dietary essential fatty acids (EFAs), as their sex pheromones (type II). In the latter species, EFAs are considered to be converted into alkenes, often after chain elongation, in specialized cells called oenocytes. These alkenes are transported through the hemolymph to the pheromone gland, from which they are secreted with or without further modifications. We confirmed that the appearance of EFA-derived alkenes in the hemolymph was closely associated with the completion of pheromone gland formation in an arctiid moth Eilema japonica. Analyses of the hemolymph of several moth species utilizing type-I sex pheromones demonstrated the occurrence of (Z,Z,Z)-3,6,9-tricosatriene (T23), a typical type-II component, in the hemolymph of a noctuid Mamestra brassicae and two crambids Ostrinia furnacalis and Ostrinia scapulalis. Our results demonstrated that moths utilizing type-I pheromones have the ability to synthesize type-II sex pheromones, and suggested that recently diverged groups of moths may have secondarily exploited EFA-derived alkenes as sex pheromones.     

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.     

INTRODUCTION: Pheromones as Tools for Olfactory Research

We have long been fascinated by the unique ability of odorsto stir our emotions and to evoke long-forgotten memories, butcertain odors play a much more fundamental role in that theyvastly improve an organism's chances for reproductive successand survival. These odorants are called pheromones, a term commonlyapplied to semiochemicals that are released by one member ofa species and evoke a specific reaction or reactions from membersof the same species. Pheromones are known for both the specificityand the potency of their actions, which can be behavioral and/orneuroendocrinological. Pheromones can stimulate individualsto aggregate, to disperse, or to react defensively in the presenceof a predator, but they are probably best known for bringingthe sexes together. Some pheromones have also been found totrigger a dramatic release of pituitary hormones in severalvertebrate species. Although first identified in insects, morerecent studies show that sex pheromones influence the livesof a wide range of organisms, from microbes to man. The hormonally-derivedsex pheromones in teleost fish, and the airborne pheromonesof moths are two systems that illustrate how scientists haveused these specialized chemical signals as important tools toinvestigate the morphology, physiology and biochemistry of olfactory-receptorsystems, the mechanisms of odor-information processing in thebrain, and the diverse range of behaviors and endocrinologicalchanges associated with pheromonal communication. While ourfocus is on these two animal models, other examples, includingmammalian pheromone systems, are also discussed. Chem. Senses21: 241–243, 1996.     

天牛成虫信息素及嗅觉感受机制研究进展

评述了天牛成虫信息素及嗅觉感受机制的研究进展。天牛雌、雄成虫均可释放性信息素,迄今已对31种天牛的性信息素进行了研究,其中完成组分鉴定的有13种。天牛性信息素包括长距离、短距离和接触性信息素3种类型。天牛性信息素存在变异现象,同种天牛分布在不同地区,其性信息素组分之间存在差异。触角是天牛感受性信息素的主要器官,也是判别成虫通讯方式的形态指标,性信息素发达的种类其触角常具显著的性二型现象。天牛利用寄主信息素（如萜烯类、醇类和酯类）寻找寄主。性信息素和寄主信息素在林间复合使用可提高诱捕率。天牛信息素还包括异种信息素、忌避信息素和产卵干扰素,能够提高天牛寄主定位效率。天牛触角嗅觉感受的神经细胞（RNs）有3类,气味信息经神经细胞群传输至中枢神经系统,神经信号按标记路线或交叉纤维样式输导。天牛气味结合蛋白（OBP）方面的研究尚未见报道。     

农业昆虫气味受体功能研究进展

昆虫主要依靠嗅觉系统寻找食物、发现配偶、控制交配、选择产卵地、逃避天敌等,因此嗅觉系统对昆虫的繁殖和生存至关重要.气味受体(odorant receptor,OR)是嗅觉系统中的关键成分之一,可被信息化合物激活引发特定行为产生.随着测序技术的发展,大量的农业昆虫的基因组和转录组被测序,从测序数据中分析获得了它们的OR家...     

Frequency coding by central olfactory neurons in the sphinx moth Manduca sexta

Sexually receptive female moths and many other insects releasechemical attractants (sex pheromones) to lure conspecific mates.Recent evidence indicates, moreover, that the odor plume formeddownwind from the female possesses a discontinuous structurethat appears to provide the searching male with orientationcues.Using intracellular methods, we find that many central olfactoryneurons in male moths (Manduca sexta) can track pulsed pheromonalstimuli precisely. The cells respond to each brief odor pulsewith a similarly brief burst of action potentials, and the separationbetween response bursts is aided by inhibitory synaptic input.Furthermore, these neurons appear to participate in at leasttwo levels of ‘feature detection’: they respondselectively to pheromonal stimuli, and they follow pulsed stimulationonly in a limited range of frequencies Above the frequency limit,the cells respond as if the male is stimulated by a prolonged,uniform concentration of pheromone. The ability of these neuronsto encode changes in the temporal characteristics of pheromonalstimuli may provide the male with positional cues to help himlocate the pheromone source over long distances.     

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.     

Joint action of quercetin with four insecticides on the cotton leaf-worm larvae, Spodoptera littoralis Boisd. (Lep. : Noctuidae) in Egypt

The naturally occurring phytoncidal chemical component of some plant- species are responsible for controlling and/or repelling insects from host plants. The use of natural products, readily available in the environment, to control the cotton leafworm, could be of help in reducing the need for applying the synthetic conventional insecticides . Moreover, crude vegetable oils application is quite safer to the non targets and the environment. The use of sex attractant pheromones as predicative tools to forecast pest population and their potential damage levels in specific crops, has significantly been limited because sex attractants are usually directed to one sex only. Thus, identification of plant constituents that attract S. littoralis Boisd. adults, especially females, and that directly affect their feeding or reproductive behaviour, would greatly expand opportunities for manipulation of the biological and environmental events that prevent the establishment, development, and dispersal of the insect-pest under study. Extracted Volatiles from certain parts of cotton plants, attracted both sexes of the cotton leafworm moths instead of attracting one sex only as the pheromones do. Plant flavonoids have been shown by many investigators to have an effect on insect behaviour, growth, and development. Quercetin is one of many bioflavonoids that exists in several fruits and vegetables. The Aim of the present work is to study in vivo the biochemical mode of action of quercetin as a synergist in combination with insecticides. The present results proved the synergistic effect of quercetin when combined with four insecticides, namely, profenofos (organophosphates), deltamethrin (pyrethroid), and tebufenozide et hexaflumuron as insect growth regulators against the studied insect-pest. Quercetin role as a synergist might be attributed to its ability to inhibit certain active oxidases, which may be responsible for in vivo detoxification of the intact insecticides when applied to insect larvae, through glutathione-S-transferase.