Identification of a sex pheromone from a rotifer

The first isolation and characterization of a sex pheromone from a zooplankter is reported. A 29 kdalton glycoprotein on the surface of females of the marine rotifer Brachionus plicatilis acts as a contact-mating pheromone. This glycoprotein (gp29) is glycosylated with oligosaccharides containing Nacetylglucosamine, mannose, and fucose residues, and these oligosaccharides are necessary for male recognition of females. Males detect this signal by contact chemoreception with receptors located in their corona. Binding of purified glycoprotein to male receptors reduces mating attempts by 93%. An antibody to the glycoprotein binds to females, reducing male mating attempts by 86%. When purified gp29 is bound to sepharose beads, it is sufficient to elicit male mating behavior. This glycoprotein is likely to play a key role in the evolution and maintenance of reproductive isolation in rotifers.     

Identification and field evaluation of the female sex pheromone of Stathmopoda masinissa in Korea

The sex pheromone of Stathmopoda masinissa Meyrick, an important pest of persimmon fruit in East Asia such as Korea, China, and Japan, was investigated. A lure using (E4,Z6)-4,6-hexadecadienyl acetate (E4,Z6-16Ac), which was identified as a sex pheromone compound of Japanese population, did not work at all for Korean population. Therefore, components in the abdominal extract of the moth were identified and their attractiveness was evaluated in the field. Two components, E4,Z6-16Ac and (E4,Z6)-4,6-hexadecadien-1-ol (E4,Z6-16OH) were identified from the extract of female abdominal extract in a ratio of 10–15:90–85 by GC–MS analysis with synthetic standards. E4,Z6-16Ac and E4,Z6-16OH were previously identified as EAG-active components of this moth in Japanese population. However, (E4,Z6)-4,6-hexadecadienal (E4,Z6-16Ald), which is one of the abdominal extract components and EAG-active component in Japanese population, was not detected in our samples. In the persimmon orchard, single component of E4,Z6-16Ac or E4,Z6-16OH was not attractive. However, the 1:1 mixture of the two components significantly increased the captures of male S. masinissa. Interestingly, traps baited with E4,Z6-16Ac captured significantly higher number of Oedematopoda ignipicta (Lepidoptera: Stathmopodidae) than the traps baited with E4,Z6-16OH or blend of the two components. The attractiveness of E4,Z6-16Ac to O. ignipicta is a new finding.     

Identification and field bioassays of the sex pheromone of the yellow-legged clearwing Synanthedon vespiformis (Lepidoptera: Sesiidae)

The yellow-legged clearwing (YLC) Synanthedon vespiformis (Lepidoptera: Sesiidae) occurs in the Mediterranean and central Europe. It is polyphagous, boring into the woody parts of broadleaf species including forest trees as well as various Rosaceae species. S. vespiformis has been reported as an economically important pest causing severe injury to stone fruit plantations. Many attractants for sesiid species were discovered by random field screening using 2,13- and 3,13-octadecadienyl alcohols, acetates and aldehydes, including one for S. vespiformis; and about 20 sex pheromones of sesiids have been identified so far. In the present study we identified the natural composition of the sex pheromone of YLC laboratory reared females as a blend of E3,Z13- and Z3,Z13-octadecadienyl acetates, at a ratio of 4:1. We developed an efficient lure for monitoring the pest. Pheromone funnel traps with rubber septa, impregnated with 1 mg pheromone blend, efficiently captured males for 10 weeks. Suspension of Shin-Etsu^? ropes containing a 2:1 blend of E3,Z13-18:Ac and Z3,Z13-18:Ac at 13.74 mg/ha/h, resulted in shutdown of trap catches in the treated plots and closely situated neighboring plots indicating that mating disruption is feasible.     

Identification, synthesis and activity of sex pheromone gland components of the autumn gum moth (Lepidoptera: Geometridae), a defoliator of Eucalyptus

Summary. The autumn gum moth, Mnesampela privata (Guenée) (Lepidoptera: Geometridae), is native to Australia and can be a pest of plantation eucalypts. Field-collected and laboratory-reared female autumn gum moths were dissected to remove glands likely to contain components of the sex pheromone. Using gas chromatography (GC) and combined gas chromatography–mass spectrometry (GC-MS), three compounds were identified from female extracts, namely (3Z,6 Z,9 Z)-3,6,9-nonadecatriene, 1-hexadecanol and 1-octadecanol (confirmed by comparison with synthetic samples). Nonadecatriene elicited an antennal response in male autumn gum moth during gas chromatographic analyses combined with electroantennographic detection (GC-EAD). In electroantennogram (EAG) recording male M. privata antennae responded to the nonadecatriene. Nonadecatriene was synthesised via Kolbe electrolysis, starting with (9Z,12Z,15Z)-octadeca-9,12,15-trienoic acid (linolenic acid) and propanoic acid or via an alternative four-step method also starting from linolenic acid. In field trials (3Z,6Z,9Z)-3,6,9-nonadecatriene proved attractive to male moths. Thus, we conclude that (3Z,6Z,9Z)-3,6,9- nonadecatriene is a sex pheromone component of autumn gum moth. This component has been identified in extracts from other geometrids in the same subfamily, Ennominae. However, to our knowledge this is the first example where (3Z,6Z,9Z)-3,6,9-nonadecatriene has been found in females and also proved attractive to male moths when presented on its own. Our results are discussed in relation to other geometrid pheromones.     

Characterization of a sex pheromone in a simultaneous hermaphroditic shrimp, Lysmata wurdemanni

Olfactory chemical cues have been described to play important roles in the control of mate recognition in many decapod crustaceans. However, we still know very little about the chemical characteristics of the cues that coordinate pre-copulative behaviour. In this study, we partially characterized a waterborne sex pheromone of a marine shrimp, Lysmata wurdemanni. Female moulting water was collected and ultrafiltered using 1,000 and 500-Da membranes, respectively, and analysed using HPLC with a Lichrosphere™ RP18 (C18) column. The sex pheromone is likely to be a molecule between 500 and 1,000 Da in size because behavioural bioassays showed that males responded to the supernatant of 500-Da and to the 1,000-Da filtrate, but did not respond to the supernatant of 1,000-Da or to the 500-Da filtrate. There was only one dominant peak (2.86 min) detectable in HPLC chromatograms of the supernatant of the 500-Da filtration. This peak showed a UV absorbance maximum at 274 nm, similar to the recently identified shore crab sex pheromone Uridine-di-phosphate (UDP). Behavioural bioassays confirmed that this peak is a bioactive component of a potential pheromone bouquet, but is different from UDP, which showed no bioactivity in Lysmata wurdemanni. Our results lay the foundation for future studies to purify and eventually identify this sex pheromone.     

Identification and biological activity of sex pheromone components from females of the plum moth Illiberis rotundata Jordan (Lepidoptera: Zygaenidae: Procridinae)

The plum moth, Illiberis rotundata Jordan (Lepidoptera: Zygaenidae: Procridinae), is a pest of orchards in Japan and China. Few chemical ecological studies have been directed towards the Zygaenidae and particularly the Procridinae. To investigate the sex pheromone of this species, extracts of pheromone glands from adult female I. rotundata were analyzed by coupled gas chromatography-electroantennography (GC-EAG) and coupled gas chromatography-mass spectrometry (GC-MS). Whilst GC-EAG on male moths showed an active peak, identified as 2-butyl (7Z)-dodecenoate, GC-MS also revealed the presence of the homologue 2-butyl (9Z)-tetradecenoate. Electroantennographic investigations, as well as field tests, strongly suggested the natural compounds to have the (R)-configuration at the stereogenic centre. Field results demonstrate 0.2 mg of a 1:1-mixture of (2R)-butyl (7Z)-dodecenoate and (2R)-butyl (9Z)-tetradecenoate to be a powerful lure that may be used in pest control measures against I. rotundata. The chemical structures of the new pheromone components show the same features as those of other zygaenid species: unsaturated fatty acids esterified with a short chain chiral alcohol. This is the first example of a two-component blend constituting the pheromone of a procridinid species.     

Attraction of field-flying aphid males to synthetic sex pheromone

Summary Transparent plastic water traps, baited with the synthetic aphid sex pheromone components (4aS,7S,7aR)-nepetalactone and (1R,4aS,7S,7aR)-nepetalactol or control lures, were placed in four semi-sheltered field sites at a height of 1.1 m. Although males of twenty-one aphid species were collected from the water traps, onlySitobion fragariae (Walker) was abundant. In total, 8 pheromone traps produced 102 males compared with only 10 males in 8 control traps. The sex pheromone released by sexual femaleS. fragariae was identified as the nepetalactone used in the lures. Aphid sex pheromones may be more species-specific than previously thought and the presence of a host plant is not essential for males to locate sexual females.     

Population differentiation in female sex pheromone and male preferences in a solitary bee

Population differentiation in female mating signals and associated male preferences can drive reproductive isolation among segregated populations. We tested this assumption by investigating intraspecific variation in female sex pheromone and associated male odour preferences among distant populations in the solitary bee Colletes cunicularius (L.) by using quantitative gas chromatography and by performing field bioassays with synthetic blends of key sex pheromone compounds. We found significant differences in sex pheromone blends among the bee populations, and the divergence in odour blends correlated positively with geographic distance, suggesting that genetic divergence among distant populations can affect sex pheromone chemistry. Our behavioural experiments, however, demonstrate that synthetic copies of allopatric female sex pheromones were cross-attractive to patrolling males from distant populations, making reproductive isolation by non-recognition of mating signals among populations unlikely. Our data also show that patrolling male bees from different populations preferred odour types from allopatric populations at the two sites of bioassays. These male preferences are not expected to select for changes in the female sex pheromone, but may influence the evolution of floral odour in sexually deceptive orchids of the genus Ophrys that are pollinated by C. cunicularius males.     

Female sex pheromone in immature insect males—a case of pre-emergence chemical mimicry?

Sexual selection by competition for mates is a formidable force that has led to extraordinary adaptations in males. Here we present results suggesting a novel case of pheromone mimicry in males of Lariophagus distinguendus, a parasitic wasp of beetle larvae that develop in stored grain. Females of L. distinguendus produce a pheromone even before they emerge from a grain. Males are attracted to the parasitised grain and wait for females to emerge. Males emerging later than others are under enormous selection pressure since females mate only once. We show evidence that developing males fool their earlier emerging competitors by mimicking the female pheromone. Males exposed to pupae of either sex exhibit typical courtship behaviour. Searching males are not only arrested by grains containing developing females but spend as much time on grains containing developing males. Hence, by distracting their competitors away from receptive females late males may increase their own chance to mate with these females. After emergence, males decompose the active compounds within 32 h probably to decrease molestation during their own search for mates. Chemical analyses of active pheromone extracts and bioassays using fractions demonstrate that the active compounds are among the cuticular hydrocarbons.     

Mating behaviour of male Carcinus maenas in relation to a putative sex pheromone: behavioural changes in response to antennule restriction

Temporary suspension of the receptivity of the male antennules confirmed these organs as the site of putative pheromone detection in the crab Carcinus maenas. Comparative analysis of male performance in individual components of sexual behaviour failed to identify any difference between male crabs with antennules restricted and others without, when individuals from each group were placed in contact with receptive females. However, even though pheromone perception by males was not a prerequisite for the initiation of sexual behaviour, in its absence the control of normal sequence and duration of pairing behaviour was disrupted.     

A sex pheromone component novel to Ostrinia identified from Ostrinia latipennis (Lepidoptera: Crambidae)

Summary. Extracts from the sex pheromone gland of Ostrinia latipennis (Lepidoptera: Crambidae) were analyzed by gas chromatography-electroantennographic detection (GC-EAD) and GC-mass spectrometry. Only an EAD-active compound was detected in the extract, and it was identified as (E)-11-tetradecenol (E11-14:OH). In a wind-tunnel bioassay, E11-14:OH elicited a series of mate finding behaviors from males, although it was far less active than virgin females and crude extract of the pheromone gland. The attractiveness of E11-14:OH to O. latipennis males was confirmed by field trapping experiments. Based on these findings, we concluded that E11-14:OH, which is novel to the genus Ostrinia, is a major component of the sex pheromone in O. latipennis. The significance of the use of alcohol in place of the usual acetates in Ostrinia is discussed in relation to the pheromone biosynthesis system. Received 9 December 1999; accepted 14 March 2000     

Evidence for a female sex pheromone mediating male trailing behavior in the red-sided garter snake, Thamnophis sirtalis parietalis

Summary. Male garter snakes locate females during the breeding season utilizing conspecific trailing behavior. It has been hypothesized that the female-derived chemical cue responsible for mediating male reproductive trailing behavior is the sexual attractiveness pheromone, a previously characterized contact pheromone responsible for releasing male courtship behavior. To examine this hypothesis, we tested the response of male red-sided garter snakes, Thamnophis sirtalis parietalis, to pheromone trails produced by males, females and ‘she-males’. She-males are a small subset of males in the natural population that are morphologically and behaviorally similar to other males except that they produce and express the sexual attractiveness pheromone during the breeding season. When tested on a Y-maze, males were found to detect and follow the skin lipid trails of females and she-males, but displayed no behavioral responses to male trails. In addition, males were unable to discriminate between she-male and female trails when given a choice. These results are consistent with the hypothesis that the sexual attractiveness pheromone is the chemical cue primarily utilized by males to mediate reproductive trailing behavior.     

Identification of trail pheromone compounds from the labial glands of the stingless bee Geotrigona mombuca

Foragers of several species of stingless bees deposit pheromone spots in the vegetation to guide recruited nestmates to a rich food source. Recent studies have shown that Trigona and Scaptotrigona workers secrete these pheromones from their labial glands. An earlier report stated that species within the genus Geotrigona use citral from their mandibular glands for scent marking. Since convincing experimental proof for this conjecture is lacking, we studied the glandular origin of the trail pheromone of Geotrigona mombuca. In field bioassays, newly recruited bees were diverted by artificial scent trails that branched off from the natural scent trail deposited by their nestmates only when they were baited with extracts from the foragers’ labial glands. Compounds extracted from the mandibular glands, however, did not release trail following behavior. This demonstrates that the trail pheromone of G. mombuca is produced in the labial glands, as in Trigona and Scaptotrigona. Furthermore, in chemical analyses citral was identified exclusively in the foragers’ mandibular glands, which disproves its supposed role as a trail pheromone. The labial glands contained a series of terpene- and wax type esters, with farnesyl butanoate as major constituent. We, therefore, postulate that the trail pheromone of G. mombuca is composed of a blend of esters.     

外来有害生物风险评估技术

概述了有害生物风险分析的概念、必要性、生物学基础和一般程序 ;论述了生态气候图、农业气候相似距库、生态气候评价的分析模型、地理信息系统、专家系统、基于定性分析与定量估算相结合的数学模型等有害生物风险分析技术的原理和特点 ;认为应用网络技术 ,建立基于分布式计算的全球入侵物种风险评价数据体系 ,可有效提高风险评价的速度和准确性。     

(Z)-11-Pentacosene is the major sex pheromone component inDrosophila virilis (Diptera)

Summary A crude cuticular extract from 3450 virgin 9–13 day old female fruit flies(Drosophila virilis), was subjected to chromatography accompanied by bioassay for sex pheromone activity. After three chromatographic steps, fractions containing active monoenes and dienes were obtained. Chemical analysis by infrared absorption, gas liquid chromatography and gas chromatography/mass spectrometry of the active fraction indicated that active monoenes were comprised chiefly of (Z)-11-pentacosene (abbreviated (Z)-11-C_25:1), (Z)-13-C_27:1, (Z)-13- and (Z)-14-C_29:1. Synthetic monoenes were made, and only (Z)-11-C_25:1 elicited good courtship behaviour in maleD. virilis. Therefore it was concluded that (Z)-11-C_25:1 was a major sex pheromone. A total of 16.2±1.32 µg of cuticular hydrocarbons was isolated from 10 day old females, including 5.9±0.56 µg of (Z)-11-C_25:1. An additive effect was suggested from the higher observed courtship response when using a mixture of active dienes with the active monoene.     

Release of sex pheromone and its precursors in the pine sawfly Diprion pini (Hym., Diprionidae)

Summary. The first identification of a sex pheromone of a pine sawfly (Hymenoptera, Diprionidae) dates back almost thirty years. Since then, female-produced pheromones of over twenty diprionid species have been investigated by solvent extraction followed by separation and identification. However, no study has shown what the females actually release. Collection of airborne compounds using absorbtion on charcoal filter as well as solid phase microextraction (SPME) followed by analysis employing gas chromatography combined with mass spectrometry (GC-MS), revealed an unusual system in Diprion pini, in which the pheromone precursor alcohol, 3,7-dimethyl-2-tridecanol, is released together with acetic, propionic, butyric and isobutyric acids. The corresponding acetate, propionate and butyrate esters of 3,7-dimethyl-2-tridecanol were also found in the samples. All esters were electrophysiologically active, and the propionate and isobutyrate were attractive in trapping experiments. Based on these and earlier reported results, it seems that at least in part of its range, the pheromone response of D. pini is not very specific with regard to the functional group, as long as this is an ester.