Moth Sex Pheromone Research Articles

Expression and evolution of Δ 9 and Δ 11 desaturase genes in the moth Spodoptera littoralis

Desaturation of fatty acids is a key reaction in the biosynthesis of moth sex pheromones. The main component of Spodoptera littoralis sex pheromone blend is produced by the action of Δ 11 and Δ 9 desaturases. In this article, we report on the cloning of four desaturase-like genes in this species: one from the fat body (Sls-FL1) and three (Sls-FL2, Sls-FL3 and Sls-FL4) from the pheromone gland. By means of a computational/phylogenetic method, as well as functional assays, the desaturase gene products have been characterized. The fat body gene expressed a Δ 9 desaturase that produced ( Z)-9-hexadecenoic and ( Z)-9-octadecenoic acids in a (1:4.5) ratio, whereas the pheromone gland Sls-FL2 expressed a Δ 9 desaturase that produced ( Z)-9-hexadecenoic and ( Z)-9-octadecenoic acids in a (1.5:1) ratio. Although both Δ 9 desaturases produced ( Z)-9-tetradecenoic acid from myristic acid, transformed yeast grown in the presence of a mixture of myristic and ( E)-11-tetradecenoic acids produced ( Z, E)-9,11-tetradecadienoic acid, but not ( Z)-9-tetradecenoic acid. The Sls-FL3 gene expressed a protein that produced a mixture of ( E)-11-tetradecenoic, ( Z)-11-tetradecenoic, ( Z)-11-hexadecenoic and ( Z)-11-octadecenoic acids in a 5:4:60:31 ratio. Despite having all the characteristics of a desaturase gene, no function could be found for Sls-FL4.

Desaturases from the spotted fireworm moth ( Choristoneura parallela) shed light on the evolutionary origins of novel moth sex pheromone desaturases

Six acyl-CoA desaturase-encoding cDNAs from mRNA isolated from the spotted fireworm moth, Choristoneura parallela (Lepidoptera: Tortricidae) were characterized and assayed for functionality. The expression levels of these cDNAs were determined in the pheromone gland and fat body by real-time PCR and the resulting patterns are in line with results from published studies on other moth sex pheromone desaturases. The cDNAs were found to correspond to six genes. Using both biochemical and phylogenetic analyses, four of these were found to belong to previously characterized desaturase functional groups [the Δ10,11, the Δ9 (16>18) and the Δ9 (18>16) groups]. A desaturase highly expressed in the pheromone gland was a novel E11 desaturase that was specific to 14-carbon precursor acids. The fifth gene [CpaZ9(14–26)] was found to display a novel Z9 activity indicating that it belongs to a new Δ9 functional group, whereas the sixth gene was determined to be nonfunctional with respect to desaturase activity. In accordance with previous studies, we find that desaturases of the Δ10,11 and Δ14 groups, which are the fastest evolving desaturases and possess the novel pheromone biosynthetic function, are expressed primarily in the pheromone gland whereas all other desaturases, which do not possess the novel reproductive function, evolve more slowly and display the ancestral metabolic function and pattern of gene expression.

Sublethal effects of larval treatment with deltamethrin on moth sex pheromone communication system of the Asian corn borer, Ostrinia furnacalis

The first, third, and fifth instar larvae of Asian corn borer, Ostrinia furnacalis (Guenée) (Lepidoptera: Pyralidae), were treated with a lethal dose 30% of deltamethrin to determine its sublethal effects on chemical communication of the adult survivors. The capability of all males surviving deltamethrin to contact the pheromone source in a wind tunnel was significantly reduced, but those treated as the first and third instars also exhibited lower percentages of `orientation,' `up-wind flight,' and `approaching' behaviors than the control males. Female moths from the deltamethrin treatment exhibited similar calling periodicity and percentages to the control moths during 10-h scotophase. However, approximately 20% of the females that survived the pyrethroid in the first and third instars contained significantly higher amounts of sex pheromone and wider coefficients of variation of the ratio of E12-tetradecenyl acetate to its Z isomer in those female survivors. There was no significant difference in the pheromone titers and coefficients of variation in control females and the females treated in the fifth instars. The present study indicates that the Asian corn borer may possess a compensation system by which the males that survived treatment at larval stage present a lower response to the pheromone, while the female survivors produce and release more pheromone.

First semi-synthetic preparation of sex pheromones

Here we describe the first construction of a genetically modified plant (GMP) with the ability to produce moth sex pheromone precursors. Previously prepared (Svatos et al., Czech Patent Appl. 2000/0125) N. tabacum GMP transformed with a plasmid encoding cabbage looper moth (Trichoplusia ni, Hubner, Lepidoptera, Noctuidae) acyl-CoA Δ11-(Z)-desaturase (Knipple et al., Proc. Natl. Acad. Sci. USA, 1998, 95, 15287) showed a substantial presence (ca. 6%) of the potential pheromone precursor, methyl (11Z)-hexadec-11-enoate (1). The ester 1 was isolated in bulk (6.5% of extracted lipids) from a greenhouse cultivated transgenic tobacco and the corresponding acetate, which are principal components of a large number of sex pheromones, was semi-synthetically prepared from the in planta produced pheromone precursor. The attractiveness of the prepared blends for moth, Mamestra brassica was proved in field trials.

Molecular genetics and evolution of pheromone biosynthesis in Lepidoptera

A great diversity of pheromone structures are used by moth species (Insecta: Lepidoptera) for long-distance mating signals. The signal/response channel seems to be narrow for each species, and a major conundrum is how signal divergence has occurred in the face of strong selection pressures against small changes in the signal. Observations of various closely related and morphologically similar species that use pheromone components biosynthesized by different enzymes and biosynthetic routes underscore the question as to how major jumps in the biosynthetic routes could have evolved with a mate recognition system that is based on responses to a specific blend of chemicals. Research on the desaturases used in the pheromone biosynthetic pathway for various moth species has revealed that one way to make a major shift in the pheromone blend is by activation of a different desaturase from mRNA that already exists in the pheromone gland. Data will be presented to support the hypothesis that this process was used in the evolution of the Asian corn borer, Ostrinia furnacalis species. In that context, moth sex-pheromone desaturase genes seem to be evolving under a birth-and-death process. According to this model of multigene family evolution, some genes are maintained in the genome for long periods of time, whereas others become deleted or lose their functionality, and new genes are created through gene duplication. This mode of evolution seems to play a role in moth speciation, as exemplified by the case of the Asian corn borer and European corn borer, Ostrinia nubilalis species.

Moth sex-pheromone biosynthesis is inhibited by the herbicide diclofop

Pheromones of nocturnal moths are derived from fatty acids produced as a result of the activity of acetyl-CoA carboxylase. This timely production is initiated in nocturnal moths by a tropic peptide, pheromone biosynthesis activating neuropeptide released into the hemolymph. In monocotyledonous plants, specific plastid acetyl-CoA carboxylase is inhibited by herbicides that target the eukaryotic form of the enzyme. We report evidence that these herbicides can also target pheromone biosynthesis by a moth, thereby implicating the acetyl-CoA carboxylase as a key regulatory enzyme in the pheromone biosynthetic pathway. These findings, whilst indicating the possible action of such herbicides on non-target organisms, also suggest a novel alternative method of insect pest management, which precludes sex-pheromone production and mating success, thereby reducing insect population growth.

Molecular genetics and evolution of pheromone biosynthesis in Lepidoptera.

A great diversity of pheromone structures are used by moth species (Insecta: Lepidoptera) for long-distance mating signals. The signal/response channel seems to be narrow for each species, and a major conundrum is how signal divergence has occurred in the face of strong selection pressures against small changes in the signal. Observations of various closely related and morphologically similar species that use pheromone components biosynthesized by different enzymes and biosynthetic routes underscore the question as to how major jumps in the biosynthetic routes could have evolved with a mate recognition system that is based on responses to a specific blend of chemicals. Research on the desaturases used in the pheromone biosynthetic pathway for various moth species has revealed that one way to make a major shift in the pheromone blend is by activation of a different desaturase from mRNA that already exists in the pheromone gland. Data will be presented to support the hypothesis that this process was used in the evolution of the Asian corn borer, Ostrinia furnacalis species. In that context, moth sex-pheromone desaturase genes seem to be evolving under a birth-and-death process. According to this model of multigene family evolution, some genes are maintained in the genome for long periods of time, whereas others become deleted or lose their functionality, and new genes are created through gene duplication. This mode of evolution seems to play a role in moth speciation, as exemplified by the case of the Asian corn borer and European corn borer, Ostrinia nubilalis species.

Comparative sex pherome biosynthesis in Thaumetopoea pityocampa and T. processionea: a rationale for the phenotypic variation in the sex pherome within the Genus Thaumetopoea

The female sex pheromones of the Mediterranean processionary moths ( Thaumetopoea sp.) are conjugated dienes or enynes of 16 carbon atoms with the unsaturations located at C11 and C13. To investigate the biochemical basis of this phenotypic variation, the biosynthetic pathway of T. processionea sex pheromone, a diene acetate, has been elucidated and compared to that reported for the enyne-producing species T. pityocampa. Mass labeling experiments showed that T. processionea sex pheromone is biosynthesized from palmitic acid, by subsequent ( Z)-11 and ( Z)-13 desaturations and final reduction and acetylation. The Pheromone Biosynthesis Activating Neuropeptide (PBAN) activates this biosynthetic pathway downstream of the dienoate intermediate. When either 11-hexadecynoic acid or ( Z)-13-hexadecen-11-ynoic acid were administered to T. processionea, this species was able to produce the enyne sex pheromone of T. pityocampa upon PBAN stimulation. In contrast, T. pityocampa does not produce either 11-hexadecynyl acetate or ( Z, Z)-11,13-hexadecadienyl acetate, despite having the corresponding precursors in the pheromone gland. However, both acetates are detected after administration of the corresponding alcohols. These overall results suggest that the absence of Δ 11 acetylenase and the existence of an enynoate specific reductase in the diene and enyne-producing Thaumetopeae, respectively, account for the different sex pheromones produced by the two groups.

Biosynthesis of sex pheromones in moths: stereochemistry of fatty alcohol oxidation in Manduca sexta

Six chiral deuterium labelled metabolic probes, ( R) and ( S)-enantiomers of [1,10,10- 2H 3]-hexadecan-1-ol, (11 E)-[1,10,10- 2H 3]-hexadec-11-en-1-ol and (11 Z)-[1,10,10- 2H 3]-hexadec-11-en-1-ol, were synthesized to examine the stereospecificity of the fatty alcohol oxidase from the female pheromone gland of the tobacco hawk moth ( Manduca sexta, Sphingidae). Both in vitro and in vivo oxidations were found to proceed by selective removal of the C1–H R hydrogen or deuterium atom ( Re-specificity) to yield the corresponding aldehydes. ( R) and ( S)-enantiomers of deuterium labelled salicyl alcohol and 2-thienyl-methanol, compounds entirely chemically diverse from the natural pheromone precursors, were also oxidised Re-specifically to salicylaldehyde and 2-thiophenecarb-aldehyde, respectively.

Evolution of moth sex pheromones via ancestral genes.

Mate finding in most moth species involves long-distance signaling via female-emitted sex pheromones. There is a great diversity of pheromone structures used throughout the Lepidoptera, even among closely related species. The conundrum is how signal divergence has occurred. With strong normalizing selection pressure on blend composition and response preferences, it is improbable that shifts to pheromones of diverse structures occur through adaptive changes in small steps. Here, we present data supporting the hypothesis that a major shift in the pheromone of an Ostrinia species occurred by activation of a nonfunctional desaturase gene transcript present in the pheromone gland. We also demonstrate the existence of rare males that respond to the new pheromone blend. Their presence would allow for asymmetric tracking of male response to the new blend and, thus, evolution of an Ostrinia species with structurally different sex pheromone components.

Aggressive chemical mimicry of moth pheromones by a bolas spider: how does this specialist predator attract more than one species of prey?

The bolas spider, Mastophora hutchinsoni, attracts Lacinipolia renigera and Tetanolita mynesalis males by mimicking the female moth sex pheromones. However, as the prey species use completely different pheromone blends we conducted experiments to determine how this is accomplished by the predator. The periodicity of L. renigera mate-seeking activities occurs early in the scotophase, whereas male T. mynesalis are active late at night, corresponding with periods when these moths are captured by the spider. The pheromone blend of early-flying L. renigera interferes with attraction of late-flying T. mynesalis to its pheromone in a dose-dependent manner, suggesting the spider must always produce a single sub-optimal “compromise” blend for both species or that it adjusts its allomonal blend to optimize capture of the respective prey species at different times during the night. We delayed (L. renigera) or advanced (T. mynesalis) the periodicity of male activity through photoperiodic manipulation and found that the bolas spider attracted both prey species outside their normal activity windows. These results support the idea that bolas spiders produce components of both species at all times rather than producing the pheromone of each prey species at different times of the night. However, using coupled gas chromatography-electroantennography, we also demonstrated that the spider decreases its emission of the L. renigera pheromone over the course of the night. This modification should reduce the behavioral antagonism of the L. renigera pheromone on T. mynesalis males and increase the predator's success of attracting T. mynesalis during this prey's normal activity window late at night.

Field and Laboratory Responses of Male Codling Moth (Lepidoptera: Tortricidae) to a Pheromone-Based Attract-and-Kill Strategy

A case study of a pheromone-based attract-and-kill management strategy for codling moth, Cydia pomonella (L.), was conducted to examine key insect behavioral factors mitigating the possible effectiveness of this strategy. Last Call CM is a newly registered attracticide product that combines the primary component of codling moth sex pheromone with the insecticide permethrin. Studies of competition between pheromone point sources within caged trees showed individual attracticide droplets were significantly more attractive to male moths than calling females. In commercial orchard blocks, marked male moths were recaptured after visiting attracticide droplets applied at rates of 50, 100, and 200 droplets/ha, although no marked moths were recaptured in plots with 500 droplets/ha. This experiment also revealed no significant differences among 0, 50, 100, and 200 droplets/ha in suppressing total catch in female-baited traps, nor were total numbers of females attracting at least one male reduced significantly. In plots with 500 droplets/ha applied, male moth catch was suppressed significantly compared with catches in untreated control plots, and the number of females attracting at least one male was reduced significantly as well. Experiments investigating sublethal physiological effects of attracticide exposure upon mating competency of male codling moths demonstrated male leg autotomy at 1, 24, 48, and 72 h after exposure. Male codling moth at 1, 24, 48, and 72 h after exposure placed near calling virgin females exhibited significant behavioral differences from sham-treated males in courtship and mating. These results clarify some of the possible mechanisms, and strengths and weaknesses of this attract-and-kill management strategy for codling moth.

Internet programs for drawing moth pheromone analogs and searching literature database.

An Internet web page is described for organizing and analyzing information about lepidopteran sex pheromone components. Hypertext markup language (HTML) with JavaScript program code is used to draw moth pheromone analogs by combining GIF bitmap images for viewing by web browsers such as Netscape or Microsoft Intemet Explorer. Straight-chain hydrocarbons of 5-22 carbons with epoxides or unsaturated positions of E or Z geometrical configuration with several altemative functional groups can be drawn by simply checking menu bars or checkboxes representing chain length, E/Z unsaturation points, epoxide position and chirality, and optional functional groups. The functional group can be an aldehyde, alcohol, or ester of formate, acetate, propionate, or butyrate. The program is capable of drawing several million structures and naming them [e.g., (E,E)-8,10-dodecadien-1-ol and abbreviated as E8E10-12:OH]. A Java applet program run from the same page searches forthe presently drawn structure in an intemal database compiled from the Pherolist, and if the component is found, provides a textarea display of the families and species using the component. Links are automatically specified for drawn components if found in the Pherolist web site (maintained by H. Am). Windowed links can also be made to two other JavaScript programs that allow searches of a web site database with over 5900 research citations on lepidopteran semiochemicals and a calculator of vapor pressures of some moth sex pheromone analogs at a specified temperature. Various evolutionary and biosynthetic aspects are discussed in regard to the diversity of moth sex pheromone components.

Ligand-receptor interaction under periodic stimulation: a modeling study of concentration chemoreceptors.

The first step of chemosensory transduction consists in the association of ligand molecules with receptor proteins borne by the cell membrane. In this article, the time evolution of ligand-receptor complexes is studied in the presence of a periodically changing ligand concentration. This type of stimulation is a close approximation to some natural situations, for example in olfaction. The transient and steady-state periodic levels of the complexes, resulting from a single-step (binding) or double-step (binding and activation) reaction, are determined. When possible, analytical solutions are given, if not for the complete model, at least for its simplified version at low ligand concentration. Otherwise, solutions are found numerically and both the complete and simplified versions of the model are compared. The results obtained are discussed with respect to actual experimental data based on the moth sex-pheromone receptor. Periodic steady states are achieved very quickly and their amplitude decreases when the stimulation frequency increases. We show that the simplified description is adequate if only a fraction of activated receptors is sufficient to produce the maximum response, as is actually the case in the example treated. The role of the frequency of stimulation is investigated and it is shown to possess an optimal range between 2 and 5 Hz.

Thiafatty acids as tracers to investigate biosynthetic pathways of lepidopteran sex pheromones

In order to investigate the potential utility of thiafatty acids as tracers for biosynthetic studies of moth sex pheromones, a series of thiatetradecanoic acids, namely 8-, 9-, 10-, 11-, 12- and 13-thiatetradecanoic, were prepared and their metabolism was investigated in pheromone glands of Spodoptera littoralis. Analysis by gas chromatography coupled to mass spectrometry of extracts from pheromone glands treated with the above acids showed that only 8-thiatetradecanoic acid and 13-thiatetradecanoic acid were metabolized by desaturation and were incorporated into the sex pheromone biosynthetic pathway. 13-Thiatetradecanoic acid was converted into ( E)- and ( Z)-13-thiatetradec-11-enoic acids, ( Z, E)-13-thiatetradeca-9,11-dienoic acid, 11-thiadodecanoic acid, ( E)- and ( Z)-11-thiadodec-9-enoic acids and 15-thiahexadecanoic acid. 8-Thiatetradecanoic acid gave rise to two monoenoic thiafatty acids and two dienoic thiafatty acids, which were assigned to ( Z)- and ( E)-8-thiatetradec-11-enoic acids, ( Z, E)-8-thiatetradeca-9,11-dienoic acid and ( E, E)-8-thiatetradeca-10,12-dienoic acid. The other thiafatty acids tested, 9-, 10-, 11- and 12-thiatetradecanoic acids, were not metabolized by desaturation, although the corresponding products of β-oxidation and chain elongation were detected. The occurrence of sulfoxides was not detected in this case, in disagreement with results on the metabolism of some thiaacids previously reported by other authors in yeast, Saccharomyces cerevisiae.

Laboratory and field experiments towards the development of an attract and kill strategy for the control of the codling moth, Cydia pomonella

AbstractA viscous formulation based on castor oil containing the pyrethroid insecticide cyfluthrin and E8, E10‐dodecadienol, the main component of the codling moth sex pheromone, (Cydia pomonella L.: Tortricidae, Olethreutinae) was developed. The insecticidal performance of the formulation was evaluated in the laboratory using a tarsal‐contact bioassay. The pheromone dosage required to attract male moths to the formulation was determined in behavioural tests performed in a wind tunnel. The efficacy of formulations applied to seedlings of the host plant was further investigated in glasshouse experiments conducted with male moths in small wire‐gauze cages. The laboratory tests resulted in a formulation for preliminary field trials containing 4% cyfluthrin and 0.1% pheromone. During the 1995 growing season, experiments were conducted in apple orchards at three locations in Germany. The formulation was first applied to the bark of apple trees (Malus domestica) in mid May and then again in late July. A good level of control, comparable with a spray treatment using the insect growth regulator Alsystin was achieved. The potential of the attract and kill strategy, combining selective attraction of a pest species with the efficacy associated with a pyrethroid insecticide treatment, as a means of controlling the codling moth in commercial apple growing, is discussed.

Hydroalumination of 3-butyn-1-ol: Application to a stereoselective synthesis of (3 E,5 Z)-3,5-dodecadienyl acetate, the sex pheromone of the leaf roller moth

Hydroalumination-iodinolysis of 3-butyn-1-ol ( 2) provided E-4-iodo-3-buten-1-ol (4E) as the major product. This compound was transformed in three steps into the leaf roller moth sex pheromone 1 with high (>99% de) stereoselectivity and good overall yield (4 steps, 39% from 2).

Identification of Novel Synthetic Octopamine Receptor Agonists Which Inhibit Moth Sex Pheromone Production

The present study was designed to identify specific and sensitive compounds which may act as specific inhibitors of pheromone biosynthesis in the moth Helicoverpa armigera using physiological bioassays and three-dimentional quantitative structure–activity relationship studies. Twenty-eight octopamine agonists were initially screened using an in vivo bioassay for pheromone production by female moths. Fourteen compounds were found to inhibit pheromone production in the moths to a level of 50% or more and were subsequently used in dose-response studies to determine ID5s. The dose-response studies were performed in vitro, analyzing the effect of these compounds on intracellular cAMP production as well as on the de novo pheromone biosynthesis. Six active derivatives, with activity in the nanomolar range, were identified with the following order of decreasing pheromonostatic activity: 2-(2, 6-dimethylanilino)imidazolide > 2-(2-methyl-4-chloroanilino)oxazolidine > clonidine > 2-(2,6-diethylanilino) thiazolidine > 2-(3,5-dichloroben zylamino)-2-oxazoline > tolazoline. Six other compounds were less active, with ID5s in the micromolar range. The active compounds were utilized for the development of a predictive model using physicochemical parameters. The results of the present study indicate that these derivatives could provide useful information in the characterization and differentiation of octopaminergic receptor types and subtypes.

Comparative efficacy of two controlled‐release gypsy moth mating disruption formulations

AbstractThe effects of aerial applications of the gypsy moth sex pheromone, disparlure, on mating disruption and suppression of growth of populations of the gypsy moth, Lymantria dispar (L.), were investigated. Two formulations of disparlure, plastic laminate flakes applied in a single application and polymethacrylate beads applied in two applications, were compared in two separate tests conducted in 1993 and 1994. The beads were applied in two applications spaced 2 weeks apart because preliminary tests had indicated that they released pheromone too rapidly to maintain adequate emission rates throughout the period of male flight. In 1993, the flakes were applied at a rate of 50 g a.i./ha, and the beads were applied at a rate of 15 g a.i./ha for each application. In 1994, the flakes were applied at a rate of 75 g a.i./ha and the beads were applied at rates of 32.5 and 42.5 g a.i./ha for the two applications. Beads with larger average particle size were used in 1994 to prolong disparlure release. The treatments applied in 1993 resulted in >97% reduction in mating and >82% suppression of population growth in the following year. Because of a 1995 collapse of gypsy moth populations in the vicinity of the tests, reliable population growth data were not available for the treatments applied in 1994, but significant mating disruption did occur under both treatments. Based on measurements of residual disparlure after field aging, the flakes released 32 and 48% of their disparlure content during the 6 weeks of male moth flight in 1993 and 1994, respectively. The smaller beads used in 1993 released 75% of their disparlure content, and the larger beads used in 1994 released 52% of their disparlure content, during the 6 weeks of male flight. The biological efficacy data suggest that the bead and flake formulations, as applied in these tests, have similar effects on gypsy moth mating disruption and subsequent population growth. Based on the observed release rates from both 1993 and 1994, a single application of the beads would provide emission rates equal to or greater than those provided by the flakes when applied at an equal dose.

Attractant or Pheromone: The Case of Nasonov Secretion and Honeybee Swarms

Honeybees are attracted to a variety of odors, including the secretion of their Nasonov glands, a secretion that has been widely assumed to be an orientation and attraction pheromone. A crossover design experiment comparing synthetic Nasonov secretion with linalool, oil of clove, skatole, and wax moth sex pheromone was established to determine if Nasonov secretion serves as a true pheromone or is simply a general attractant for honeybee swarms. None of the test odors was more attractive than odorless controls, and in all comparisons, synthetic Nasonov secretion was significantly more attractive than the test odors or odorless controls. The results confirm that Nasonov secretion is a true pheromone in the context of attracting honeybee swarms to nest cavities and that environmentally present or apparent odors play little or no role in honeybee nest-seeking behavior.