Male Sex Pheromone Research Articles

Inhibition of male corpora allata activity and sexual pheromone responsiveness in the black cutworm, Agrotis ipsilon, by the hypocholesterolemic agent, fluvastatin

Male sexual behavior of the black cutworm Agrotis ipsilon is controlled by corpora allata. Allatectomies performed on day-1 and day-3 males inhibited the typical sexual behavior in day-4 males when exposed to female pheromone in a wind tunnel. Both JH-III and JH-III acid were able to restore male sexual behavior, suggesting that corpora allata act through their endocrine activity. We demonstrated that corpora allata incubated in vitro produced only the acid form of JH-III and JH-II. Fluvastatin, an HMG-CoA reductase inhibitor, inhibited JH acid biosynthesis by the corpora allata when fluvastatin was added to incubation medium or injected in males 4 h before the bioassay. However, endocrine activity of CA resumed 5–6 h after injection, indicating that the effect of fluvastatin was temporary. Fluvastatin injection also induced temporary inhibition of male responsiveness. © 1996 Wiley-Liss, Inc.

Structure of the sex pheromone-producing prothoracic glands of the male old house borer, Hylotrupes bajulus (L.) (Coleoptera : Cerambycidae)

Pheromone glands were discovered in the prothorax of male Hylotrupes bajulus (L.) (Coleoptera : Cerambycidae). These exocrine glands were investigated by SEM and light microscopy. Almost the entire prothorax is internally lined with a glandular matrix composed of numerous heap-like complex glands. Each gland is divided into several subunits (“pore field units”), which in turn are composed of a varying number of glandular units. The glandular unit comprises a distal voluminous glandular cell, a medial (intercalary) canal cell I, and a minute canal cell II near the cuticle. The spindle-like, basally constricted receiving canal of the gland cell leads into the long, non-porous conducting canal, which, by a single cuticle canal, opens in an external pore field, an aggregate of orifices of other such cuticle canals. In varying numbers, these randomly arranged pore fields are located in superficial pits that are distributed over nearly the entire prothorax. The structure of these male sex pheromone glands is discussed in comparison with other known glands in species of Coleoptera characterized by multicellular aggregations and by pore plates.

Identification of oviposition attractants for the sandfly Lutzomyia longipalpis (Diptera: Psychodidae) in volatiles of faeces from vertebrates

Abstract. Extracts of volatiles from rabbit and chicken faeces preferentially attracted gravid sandflies, Lutzomyia longipalpis (Lutz and Neiva), in an oviposition bioassay. In electrophysiology experiments, the same extracts selectively stimulated two olfactory cells while inhibiting another in ascoid sensilla on the antennae of these flies. Analysis of faeces volatiles by gas chromatography linked to ascoid sensillum recording revealed two early eluting electrophysiologically active components of rabbit faeces. These active compounds were identified in both rabbit and chicken faeces volatile extracts by gas chromatography ‐mass spectrometry as hexanal and 2‐methyl‐2‐butanol. Hexanal stimulated one cell type and inhibited another, whereas 2‐methyl‐2‐butanol stimulated a third cell type. A 1:l mixture of synthetic hexanal and 2‐methyl‐2‐butanol elicited the same targeted oviposition response from gravid females on the treatment septum of the bioassay as did the total volatile extract of rabbit or chicken faeces.The monoterpenes α(+)‐pinene (plus some optical and positional isomers) and a‐terpinene activated a separate cell type, whereas benzaldehyde stimulated the same receptor as hexanal, but with a higher threshold. Furthermore, an olfactory cell selectively tuned to the perception of the male sex pheromone of this species was also found in the ascoid sensillum.

Structure, stereochemistry, and thermal isomerization of the male sex pheromone of the longhorn beetle Anaglyptus subfasciatus.

Male-released sex pheromone constituents of the longhorn beetle Anaglyptus subfasciatus (Coleoptera: Cerambycidae) are identified by GC-MS and GC-Fourier transform infrared as a 7:1 molar mixture of 3-hydroxy-2-hexanone and 3-hydroxy-2-octanone. These two compounds undergo thermal isomerization during GC analyses to give the corresponding 2-hydroxy-3-alkanones. Comparison of GC retention times of the natural products with those of synthesized enantiomerically pure compounds revealed that both semiochemicals have (R)-stereochemistry. These absolute configurations were confirmed by comparisons of the (R)-methoxy(trifluoromethyl)phenylacetic acid esters of insect-derived and synthetic samples.

Bisabolene epoxides in sex pheromone innezara viridula (L.) (Heteroptera: Pentatomidae): Role ofcis isomer and relation to specificity of pheromone

Thetrans- andcis-(Z)-α-bisabolene epoxides (trans- andcis-(Z)-αBE) are the main components of the male sex pheromone inNezara viridula. The role of thecis isomer and the importance of thecis/trans proportion for the activity and the specificity of the pheromone are not clearly elucidated and were studied here. Interindividual variation of thecis/trans proportion produced by males was studied by individual hexanic extracts in two strains originating from the south of France (SF) and French West Indies (FWI). Thetrans isomer composed 42-82% of bisabolene epoxides in SF males and 74-94% of bisabolene epoxides in FWI males. Means (± SD) significantly differ between SF (62.8%±8.4) and FWI (82.4%±5.9) males in spite of this interindividual variation. Different isomers of bisabolene epoxide were synthesized and their EAG activity on female antennae was compared. Racemictrans- andcis-(Z)-αBE elicited low EAGs, not different from the nonnaturaltrans andcis (E)-αBE that were inactive on behavior. Behavioral tests revealed that racemictrans- andcis-(Z)-αBE attracted 45% (P<0.05) and 25% (P<0.05) of females, respectively. The same levels of attraction were obtained with (-) enantiomers oftrans- andcis-(Z)-αBE, which attracted 40% (P<0.05) and 20% (P>0.05) of the females, respectively. Binary blends containing 75/25, 50/50, and 25/75 proportions ofcis/trans isomers were more attractive thantrans-(Z)-αBE alone and response of females to the 25%cis/75%trans blend was significantly more important than the response totrans-isomer alone (P<0.05). The importance of thecis/trans proportion in relation with the specificity of the male pheromone is discussed.

Effects of host plant,Gossypium hirsutum L., on sexual attraction of cabbage looper moths,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae)

Unmated female or male cabbage looper moths,Trichoplusia ni (Hübner), were attracted more often in a flight tunnel to a cage with moths of the opposite sex and a bouquet of cotton foliage. Increased sexual attractiveness of females with plants may be a result of stimulation of pheromone release in response to plant odor, since more males were attracted when odor of cotton foliage was passed over females than when odor of females was passed over cotton foliage before venting into the flight tunnel. Increased sexual attractiveness of males with plants is due in part to host odor enhancement of female attraction to male pheromone, since more females were attracted to synthetic male pheromone (a blend of enantiomers of linalool and isomers of cresol) and a cotton leaf extract than were attracted to male pheromone alone. A short synthesis procedure was developed for (S)-(+)-linalool, the major component of the male sex pheromone, isolated from hair pencils, used in these tests.

Stereochemical inversion of pyrrolizidine alkaloids byMechanitis polymnia (Lepidoptera: Nymphalidae: Ithomiinae): Specificity and evolutionary significance

Pyrrolizidine alkaloids (PAs), acquired by adults or larvae of Danainae and Ithomiinae butterflies and Arctiidae moths from plants, protect these lepidopterans against predators and are biosynthetic precursors of male sex pheromones. The investigation of PAs in many species of wild-caught adults of Ithomiinae showed lycopsamine (1) [(7R)-OH, (2'S)-OH, (3'S)-OH] as the main alkaloid. In incorporation experiments, PA-free (freshly emerged) adults of the ithomiineMechanitis polymnia were fed seven PAs: lycopsamine and four of its known natural stereoisomers-indicine (2) [(7R)-OH, (2'R)-OH, (3'S)-OH], intermedine (3) [(7R)-OH, (2'S)-OH, (3'R)-OH], rinderine (4) [(7S)-OH, (2'S)-OH, (3'R)-OH], and echinatine (5) [(7S)-OH, (2'S)-OH, (3'S)-OH], and two PAs without the 7-OH: supinine (6) [(2'S)-OH, (3'R)-OH] and amabiline (7) [(2'S)-OH, (3'S)-OH]. Males epimerized PAs 3, 4, and 5 mainly to lycopsamine (1). Females fed these same three PAs changed a smaller proportion to lycopsamine; their lesser capacity to modify PAs corresponds to their normal acquisition of already transformed PAs from males during mating rather than through visits of adults to plant sources of PAs. The alkaloids1 and2, both 7R and 3'S, were incorporated without or with minimum change by males and females. Feeding experiments with6 and7 (males only) showed an inversion at the 3' center of6 and no change in7. The inversion from 7S to 7R (probably via oxyreduction) may be closely related to the evolution of acquisition of PAs by butterflies and moths. Two hypotheses are discussed: (1) The ancestral butterflies are probably adapted to tolerate, assimilate, and use (7R)-PAs (most common in plants; all widespread 1,2-unsaturated macrocyclic PA diesters show this configuration). The development of (7R)-PA receptors in the butterflies could lead to a specialization on this configuration in two ways: to help find PA plants and to utilize these components in sexual chemical communication. A later appearance of (7S)-PAs in plants could have selected an enzymatic system for the inversion of this chiral center in order to continue producing (7R)-PA-derived pheromones. (2) The inversion would be due to the evolution of a enzyme system specialized in the transport of (7R)-PAs to the integument; the failure of this system to carry (7S)-PAs led to an enzymatic system to invert them to transportable (7R)-PAs. In this case, the 7R configuration is an effect and not a cause of (7R)-PA-derived pheromones. In both hypotheses, the partial inversion of the 3'-asymmetric center, when the butterfly was fed intermedine (3), rinderine (4), and supinine (6), could be fortuitous due to the conformation of the molecule and/or the enzymatic system.

Major component in male sex pheromone of cereal pestEurygaster integriceps puton (Heteroptera: Scutelleridae) identified as a homosesquiterpenoid

A homosesquiterpenoid, (4Z,4'E)-4-(1',5'-dimethyl-4'-heptenylidene)-1-methylcyclohexene, has been identified as a major component of the scent emitted by calling males ofEurygaster integriceps. Minor components of the scent included vanillin. TheE. integriceps male homosesquiterpenoid is an addition to the list of sesquiterpenoids identified as components of male attractant sex pheromones in pentatomoid Heteroptera.

Male sex pheromone of cockroachEurycotis floridana (walker) (Blattidae, Polyzosteriinae): Role and composition of tergites 2 and 8 secretions

InEurycotis floridana, the male calling behavior is associated with the exposition of epidermal glands located under tergites 2, 7, and 8. 4-Hydroxy-5-methyl-3(2H)-furanone and 4-hydroxy-2,5-dimethyl-3(2H)-furanone were recently identified as the specific components of tergite 7 secretion. Methylene chloride extracts of tergite 7 and its major compound 4-hydroxy-5-methyl-3(2H)-furanone attract the conspecific females at a distance. Methylene chloride extracts of tergite 8 are also attractive at a distance to the females, whereas extracts of tergite 2 had no effect on males and females. Our GC investigations showed the absence of specific compounds in tergite 2 secretions. The GC-MS analyses revealed that the male secretion of the gland under tergite 8 is mainly a mixture of (2R*, 3R*)-butanediol, 1-dodecanol and benzyl 2-hydroxybenzoate. These compounds were tested at different concentrations on their own, or as a mixture. Only (2R*, 3R*)-butanediol and 1-dodecanol were attractive for the females. Their functions, as components of the male sex pheromone, in addition with the two derivatives of the furanone are discussed.

Synthesis of (Z)-homoallylic alcohols and homoprop-2-ynylic alcohols via palladium-catalysed hydrogenolysis of prop-2-ynylic cyclic carbonates

The decarboxylation–hydrogenolysis of prop-2-ynylic cyclic carbonates which have an internal acetylenic bond with ammonium formate in the presence of a catalytic amount of [Pd(acac)2] and Bun3P afforded (Z)-homoallylic alcohols or homoprop-2-ynylic alcohols depending on the reaction conditions, however, hydrogenolysis of terminal prop-2-ynylic cyclic carbonates gave homoallylic alcohols; using (Z)-homoallylic alcohol 2b as a chiral synthon, the male sex pheromone of the pyralid moth Aphomia gularis has been synthesized.

Cockroach mating behaviors, sex pheromones, and abdominal glands (Dictyoptera: Blaberidae)

Two chemical signals are essential in all cockroach sexual behavioral sequences: the sex pheromone released by one partner, generally the female (for long distance attraction), and an aphrodisiac sex pheromone produced exclusively by male tergal glands (for female mounting and tergal contact or “feeding” behavior). Unlike the other cockroach groups, the males of the Oxyhaloinae species produce both chemical signals: the pheromone and the aphrodisiac. The occurrence of three patterns of mating behavior (A, B, and C), the production of male sex pheromones, and the existence in the male of developed sternal and tergal glands in seven related Oxyhaloinae species, make these cockroaches a useful model for studying the evolution of mating behavior patterns. The various types of mating behavior were not classified in the previous studies by Roth and Barth. In this report, they have been named type A (female in upper position), B (male in upper position), and C (male and female end to end). In type A mating, the male tergal glands, which are licked by the females, are well developed, whereas in types B and C, there is no licking of the male's tergal secretion by the females and the tergal glands are much less developed; the aphrodisiacs secreted by the tergal glands may no longer act in this case through contact chemoreception, but through an olfactory process involving volatile components. One common sex pheromone component seems to be acetoin. I suggest that the mating behavior tends from A toward B and C during the evolutionary process with a concomitant regression of the tergal glands and changes in the aphrodisiac emission levels. The mating behavioral sequences of cockroaches (Dictyoptera) and crickets (Orthoptera) show a striking degree of similarity and are probably examples of convergent evolution.

Synthesis of (+)-(R)-6-Ethyl-2,3-dihydro-2-methyl-4Hpyran-4-one -Sex-Pheromone Component of the Male Swift MothHepialus hectaL

Abstract The synthesis of the male swift moth sex pheromone component, (+)-(R)-6-ethyl-2,3-dihydro-2-methyl-4H-pyran-4-one (6), from ethyl aniline and (S)-2-methyloxirane is described.

Male and female sex pheromones produced byAcarus immobilis Griffiths (Acaridae : Acarina)

Male and female sex pheromones produced byAcarus immobilis Griffiths (Acaridae : Acarina)

4-Hydroxy-5-methyl-3(2H)-furanone and 4-Hydroxy-2,5-dimethyl-3(2H)-furanone, Two Components of the Male Sex Pheromone ofEurycotis floridana(Walker) (Insecta, Blattidae, Polyzosteriinae)

In Eurycotis floridana, male calling behavior is associated with the sex pheromone released by the anterior part of tergites. 2, 7, and 8. Glandular extracts of tergite 7 revealed a characteristic odor of caramel which is attractive at a distance for the females. We identified the two compounds responsible for this odor, 4-hydroxy-5-methyl-3(2H)-furanone and 4-hydroxy-2,5-dimethyl-3(2H)-furanone. These compounds are known to be very important as flavor components of foods, but this is the first time that they have been. identified as natural insect products. Various amounts of the identified compounds were tested, and their biological function is discussed.

Oriented flight responses of female Mediterranean fruit flies to calling males, odor of calling males, and a synthetic pheromone blend

AbstractMale Mediterranean fruit flies, Ceratitis capitata (Wiedemann), produce volatile chemicals thought to be attractive sex pheromones. We demonstrated for the first time that male odor elicits upwind flight and zigzagging upwind flight patterns in mature unmated females. Such flight patterns indicate the mechanisms involved in female location of the pheromone source and arrival at that source. Similar female oriented upwind flight responses occurred with a three component blend comprised of ethyl‐(E)‐octenoate, geranyl acetate, and E,E‐alpha farnesene. These findings clarify the role of male sex pheromone in mate‐location strategies in this species and provide new bioassay criteria for evaluating attraction responses to male pheromone and synthetic blends.

The role of the androconia in the mating behaviour of the European skipper, Thymelicus lineola, and evidence for a male sex pheromone

. Laboratory experiments were carried out to determine the role and characteristics of male scent scales (androconia), located in patches (stigmata) on the forewings of Thymelicus lineola (Ochsenheimer) (Lepidoptera: Hesperiidae). In behavioural tests, there were 30—40% fewer matings of virgin females by males with the stigmata removed or where females had their antennal sensilla covered with nail polish, when compared to sham-treated controls. These reductions occurred despite a large increase in male courtship activity. No physical contact was observed between male wings and female antennae during mating. A scanning electron microscope study of male wings and female antennae showed that: (1) lysis zones form over time on the androconia and pieces (osmo-phores) distal to these zones break off; (2) while few of these zones are present at emergence they are numerous in-day-old males; (3) during a single episode of courtship and mating approximately two-thirds of the available osmophores break off, yet the commonly observed courtship between males does not appear to result in osmophore release; and (4) osmophores were never observed on the female antennae. Electroantennogram recordings (EAGs) indicated that: (1) female antennae responded strongly to odours from male forewings but not from other parts of either males or females; (2) female antennae responded more strongly to young field-collected males than to newly-emerged or old, field-collected males; (3) female antennal response to male forewings was reduced if the androconia were scraped off, and was eliminated if the stigmata were removed; (4) male antennae gave weak EAG responses to both male and female forewings. We conclude that males release pheromone via the breakage of osmophores during courtship. We propose that the frequently observed refusals by females of courting males are at least partially dependent on the quantity or quality of male pheromone released, which are in turn correlated with the male's age and mating status.

Evolutionary aspects of perfume collection in male euglossine bees (Hymenoptera) and of nest deception in bee-pollinated flowers

A fascinating pollination system has been evolved between perfume producing flowers and perfume collecting male euglossine bees in the neotropics. Detailed investigations have contributed to an understanding of the interactions between euglossine males and flowers as a pollination system. The role which the collected perfume plays in the reproductive behaviour of euglossine bees is not fully understood. A favoured hypothesis suggests that the collected fragrances are used as precursors for male sex pheromones and thus serve to attract conspecific males or females. It is not known how perfume collection behaviour evolved. Here, an evolutionary approach presents a new hypothesis which suggests that the evolution of perfume collection in euglossine males is based upon pre-existing signals which were attractive to females and males. It is further suggested that, at the evolutionary outset, flowers mimicked nest sites to deceive nest-seeking euglossine bees. In addition, a comparative study was undertaken on the phenomena of nest-mimicking flowers in related bee families.

Identification of male cabbage looper sex pheromone attractive to females

A multicomponent pheromone produced by male cabbage looper moths that is attractive to female moths in a flight tunnel bioassay was isolated and identified. Based on analyses of hairpencil extracts of male cabbage loopers and volatiles emitted by males, the pheromone has been identified as a blend consisting of (S)-(+)-linalool,p-cresol, andm-cresol. The chirality of the major component, (S)-(+)-linalool, is important for behavioral response of females. These pheromonal compounds were also identified as volatiles released by males when males were exposed to the principal pheromone component of female cabbage loopers, (Z)-7-dodecen-1-ol acetate. The amount of male pheromone released was increased significantly when males were exposed to a combination of (Z)-7-dodecen-1-ol acetate and the odor from cabbage. Neither linalool nor the cresols were detected in volatiles from cabbage or from males exposed to cabbage odor.

Differential adaptation rates in a male moth's sex pheromone receptor neurons

Differential adaptation rates in a male moth's sex pheromone receptor neurons

An Effective Mass Trapping Method for the Control of Dacus oleae (Diptera: Tephritidae)

Research efforts during the last decade have culminated in the development of an effective trapping method for the control of the olive fruit fly, Dacus oleae (Gmelin). The method combines a food attractant, a phagostimulant, a male sex pheromone, a female aggregation pheromone with additional arrestant and aphrodisiac properties, and a hygroscopic substance on an insecticide-treated wood board. Pilot studies conducted from 1984 to 1988 have shown the efficacy of the method, as well as its limitations. The method eliminated an average of four (three to five) insecticide sprays required per season for the control of this pest, reduced pesticide use by 99% per treatment, and is being introduced gradually by the Greek Ministry of Agriculture to replace the use of bait or cover sprays that have been used for decades.