Genetic and endocrine studies of the pregnancy-blocking pheromone of mice.

Secretion of the pregnancy-blocking pheromone was stimulated by injection of depo-testosterone cypionate into females and males of inbred strains of mice which do not normally secrete the pheromone. Testosterone treatment of SJL males altered pheromone secretion so that pregnancies were blocked when the stud male was of the same inbred strain; an event that does not normally occur. Injection of epiandrosterone, androstenedione, androsterone or testosterone significantly increased pheromone secretion in SJL females, but progesterone and dehydroepiandrosterone were ineffective. Kidney weights were significantly increased by administration of androgen metabolites and the possibility of the kidney being the site of pheromone synthesis is discussed. The preputial gland can be excluded as the site of pheromone synthesis since males which are hemizygous for the Tabby-J gene and have no preputial glands blocked pregnancies as effectively as their normal littermates. Preliminary results are also presented concerning the isolation of the pregnancy-blocking pheromone from urine. Urine was analysed by gas chromatography and a peak was observed whose concentration could be correlated with secretion of the pheromone, although the compound(s) has not been identified or tested for biological activity.     

A pheromonal function for the crural glands of the onychophoran Cephalofovea tomahmontis (Onychophora: Peripatopsidae)

A characteristic feature of onychophorans is the presence of crural glands in males. These exocrine glands open on the ventral surface at the base of the legs. Their restriction to males suggests a sexual function. Histochemical staining of the glands indicates that their secretion has both a lipid and a protein component. Behavioural bioassays show that the secretion acts as a pheromone attractive to conspecific females. The production of a sex pheromone in onychophorans is discussed in relation to their ecology and phylogeny.     

Male cephalic labial gland secretions of two bumblebee species of the subgenus Cullumanobombus (Hymenoptera: Apidae: Bombus latreille) and their distribution in central Europe

The cephalic labial gland secretion of Bombus semenoviellus males was analyzed, and its chemical composition is reported for the first time. The secretion functions as sex or marking pheromone. Eighty compounds were identified in the secretion, the main one being all-trans-geranylgeranyl acetate (48%). The same compound was shown to form 87% of the labial gland secretion of B. cullumanus males. Both species are closely related and belong to the subgenus Cullumanobombus.     

Age-dependent changes in structure and function of the male labial gland in Bombus terrestris

The cephalic region of the labial gland in the buff-tailed bumblebee, Bombus terrestris, consists of numerous acini (formed by associated secretory cells and a central lumen) and connecting ducts. Age-dependent changes in secretion production (both qualitative and quantitative) are associated with changes in the amount of rough endoplasmic reticulum (RER), Golgi apparatus, and smooth endoplasmic reticulum (SER). The main secretory organelle is RER in the youngest individuals (pharate, and less-than-a-day old males), Golgi apparatus in 1-day-old males, and SER in males older than 2 days. Secretory cell death starts at 5 days of age, with maximal longevity to 10 days. Pheromone production starts immediately after eclosion, with pheromone quantities increasing until day 7. 2,3-dihydrofarnesol, the main component of the male-marking pheromone, appears in 1-day-old male glands, and reaches a maximum at 7 days of age, when its presence in the gland starts to decrease gradually. Older glands contain compounds not present in young ones. Variation in pheromone quantity and composition are reflected sensitively in the response of the queen antennae. Though queen antennae responded to gland extracts of all ages examined, maximum sensitivity was observed in response to extracts of glands 2-10 days old, while extracts of older glands gradually lose their effectiveness. Both major and minor components of the labial gland secretion extract elicited queen antennal responses suggesting that the pheromone is a multicomponent blend. Age-dependent changes in pheromone production, accumulation and tuning of pheromone activity are all synchronized approximately with male flight from the hive.     

Experiential and endocrine dependence of gonadotropin responses in male mice to conspecific urine

Previous research has shown that a urinary pheromone of female mice acts via the vomeronasal organ of the accessory olfactory system to elicit rapid release of luteinizing hormone (LH) in conspecific males. Several experiments were conducted to examine the importance of sexual experience for gonadotropin responses in male mice to female urine, male urine, saline, or mixtures of these stimuli. Both sexually naive and sexually experienced male mice had significantly higher plasma LH levels after presentations of female urine than after presentations of male urine. However, sexual experience appeared to increase the reliability of the short-latency gonadotropin response to female urine relative to a sexually neutral component of urine such as sodium chloride, and male urine appeared to suppress spontaneous LH secretion episodes in both naive and sexually experienced males. Subsequent experiments with sexually experienced subjects demonstrated that male mouse urine is a powerful suppressant of LH release in other males. Specifically, female mouse urine mixed with male urine failed to elicit LH responses in male subjects, whereas female urine mixed with saline was highly effective. Urine obtained from castrated male donors was as potent as urine from intact males in suppressing the gonadotropin response to female urine. The suppressive activity in male mouse urine thus does not appear to be critically dependent on gonadal hormones. The existence of a potent stimulatory pheromone in female urine and a potent suppressive pheromone in male urine makes male mice an excellent model system for studying the neural regulation of LH secretion.     

Nippostrongylus brasiliensis: factors influencing movement of males toward a female pheromone

Single, responding males of Nippostrongylus brasiliensis exhibited a dose-dependent movement toward a pheromone source that was derived from incubation or homogenization of female helminths in Tyrode's solution. Increases in female homogenate beyond an optimum concentration resulted in reduced male movement toward the pheromone source. Crowding of male N. brasiliensis prior to their exposure to female pheromone gradients diminished the males' response. However, crowding of females had no effect on response to the pheromone. The locomotory responses of males exposed to various mixed male and female pheromone sources reaffirmed earlier suggestions of a pheromone feedback system in which males influence the pheromone released from females.     

Molecular quantification of Saccharomyces cerevisiae α-pheromone secretion

Saccharomyces cerevisiae yeast cells court each other by producing an attractive sex pheromone specific to their mating type. Cells detect the sex pheromone from potential mates using a well-defined intracellular signalling cascade that has become a model for studying signal transduction. In contrast, the factors contributing to the production of pheromone itself are poorly characterized, despite the widespread use of the S.?cerevisiae α-pheromone secretion pathway in industrial fungal protein expression systems. Progress in understanding pheromone secretion has been hindered by a lack of a precise and quantitative pheromone production assay. Here, we present an ELISA-based method for the quantification of α-pheromone secretion. In the absence of pheromone from the opposite mating type, we found that each cell secretes over 550 mature α-pheromone peptides per second; 90% of this total was produced from MF α1. The addition of a-pheromone more than doubled total α-pheromone secretion. This technique offers several improvements on current methods for measuring α-pheromone production and will allow detailed investigation of the factors regulating pheromone production in yeast.     

Effects of pheromone plume structure and visual stimuli on the pheromone-modulated upwind flight of male gypsy moths (Lymantria dispar) in a Forest (Lepidoptera: Lymantriidae)

The pheromone-modulated upwind flight ofLymantria dispar males responding to different pheromone plume structures and visual stimuli designed to mimic trees was video recorded in a forest. Males flying upwind along pheromone plumes of similar structure generated tracks that were similar in appearance and quantitatively similar in almost all parameters measured, regardless of the experimentally manipulated visual stimuli associated with the pheromone source. Net velocities, ground speeds, and airspeeds of males flying in point-source plumes were slower than those of males flying in the wider, more diffuse plumes issuing from a cylindrical baffle. The mean track angle of males flying in plumes issuing from a point source was greater (oriented more across the wind) than that of males flying in plumes issuing from a transparent cylindrical baffle. Males flying in point-source plumes also turned more frequently and had narrower tracks overall than males responding to plumes from a cylindrical baffle. These data suggest thatL. dispar males orienting to pheromone sources (i.e., calling females) associated with visible vertical cylinders (i.e., trees) use predominantly olfactory cues to locate the source and that the structure of the pheromone plume markedly affects the flight orientation and the resultant track.     

Prostephanus truncatus mate choice on contact: does pheromone signalling by males affect their mating success?

Prostephanus truncatus is an economically important beetle pest of stored maize and cassava in the tropics. Male beetles signal using an aggregation pheromone that attracts both female and male beetles over large distances. Females preferentially orientate towards the pheromone signals of particular males when given a choice. The influence of pheromone signalling on courtship and mating success was investigated using pheromone biossays and mating trials in both of which a female made a choice between two males. Signalling was manipulated by exposing males to a Female Factor that inhibits pheromone production. The relative attractiveness of males to females based on pheromone bioassays was found not to influence short-range courtship behaviour or mating success.     

大袋蛾性信息素分泌的时辰节律和内分泌控制

本文报道用定量生测方法发现在成虫期短、无多次生殖循环、成虫不取食的鳞翅目昆虫中存在内分泌对性信息素的控制.大袋蛾Clania variegata雌虫的信息素腺体含量表现每日双峰的时辰节律.将雌虫饲养于两种光暗条件下,不同雌虫的峰期被错开,将恰在峰期前的雌虫中抽取的血淋巴注射于处于低含量期的雌虫中能诱导被注射的雌虫显著增加信息素的分泌.除头、摘除咽侧体或切断心侧体与咽侧体之间的神经均有效地消除信息素的分泌,但对摘除咽侧体的雌虫重植咽侧体却未能恢复其信息素的分泌.然而对低含量期的雌虫注射保幼激素类似物738,能诱导其显著增加信息索的分泌,而江射却未能恢复交配后雌虫的信息素分泌能力.根据本文结果讨论了Barth(1965)的假说.     

Pre-exposure modulates attraction to sex pheromone in a moth

In behavioural experiments we investigated the influence of previous short exposure to sex pheromone on subsequent response of male Spodoptera littoralis moths to sex pheromone. We found that pre-exposed males showed increased sensitivity to female sex pheromone after a single exposure to a pheromone plume compared to that found in na?ve males. The increased responsiveness lasted for at least 27 h after the exposure, showing that it was not just a short-term sensitization of the males. Exposure to the odour source without upwind movement towards the source was enough to increase the responsiveness. Physical activation without exposure to odour did not affect responsiveness. The increase in responsiveness after exposure was higher when the males were pre-exposed to natural female pheromone gland extract than when they were exposed to a higher dose of the main component, even though both odour sources elicited similar upwind attraction in na?ve males. Thus, the quality of the pheromone mixture to which males were exposed influenced the subsequent response.     

烟夜蛾雄蛾性附腺因子对雌蛾性信 息素合成的抑制作用

烟夜蛾Helicoverpa assulta处女蛾在交配后1 h,其性信息素滴度即显著降低,72 h内未见恢复。生测结果表明,烟夜蛾性信息素合成抑制因子主要来源于雄蛾性附腺。不同日龄雄蛾性附腺提取物的抑制活性无显著差异。光暗期对其活性具显著影响,暗期中雄蛾的性附腺物质对雌蛾性信息素合成具有较强抑制作用,而光期中雄蛾的性附腺物质不具抑制活性。在暗期的不同时间处理,对处女蛾性信息素合成的抑制作用无显著差异。雄蛾性附腺提取物对雌蛾性信息素合成的抑制作用与注射剂量有明显的相关性,0.2 ME（雄蛾当量）是产生显著抑制作用的最小剂量。对交配雌蛾注射性信息素生物合成激活神经肽（PBAN）提取物后,其性信息素合成又可恢复,这说明雌蛾交配后,性信息素滴度降低的原因是由于缺少了PBAN的调控。     

蚜虫雄蚜与雌性母对性信息素及植物挥发物的田间反应

田间观察了桃蚜Myzus persicae (Sulzer)、绣线菊蚜Aphis spiraecola Patch 、山楂圆疣蚜Ovatus crataegarius (Walker)等3种蚜虫对性信息素[(4aS,7S,7aR)-荆芥内酯和 (1R,4aS,7S,7aR)-荆芥醇]的反应,并且调查了性信息素与植物挥发物对桃蚜的田间引诱活性的相互作用.在有冬寄主或夏寄主植物的田中,性信息素诱捕器诱捕到桃蚜雄蚜与雌性母的数量显著多于对照诱捕器的诱捕数;但在非寄主植物的田中,却引诱不到桃蚜.苯甲醛(冬寄主植物桃树Prunus persica的主要挥发物组分之一)能够增强桃蚜雄蚜的引诱作用.绣线菊蚜雄蚜和雌性母对植物中提取的荆芥内酯有反应,而山楂圆疣蚜雄蚜和雌性母对植物中提取的和人工合成的荆芥内酯都没有反应,但对荆芥醇有反应.并且在荆芥醇中添加荆芥内酯之后对山楂圆疣蚜雄蚜引诱活性显著提高.还讨论了雌性蚜产生化合物被雄蚜作为性信息素、被雌性母作为聚集信息素以及性信息素与寄主植物挥发物的相互作用.     

<Emphasis Type="Italic">S</Emphasis>-isorobinal as the female sex pheromone from an alarm pheromone emitting mite, <Emphasis Type="Italic">Rhizoglyphus setosus</Emphasis>

The female sex pheromone of Rhizoglyphus setosus Manson (Astigmata: Acaridae) was identified as S-isorobinal (4S-4-isopropenyl-3-oxo-1-cyclohexene-1-carboxyaldehyde), which stimulated males sexually and enhanced the frequency of the male’s tapping and mounting behavior. Although the female hexane extract indicated no sign of sex pheromone activity against tested males, possibly due to the presence of the alarm pheromone neryl formate, an SiO₂ column fraction containing isorobinal elicited sex pheromone activity at a dose of one female equivalent. The stereochemistry of natural isorobinal was identified as S by an HPLC using a chiral column. Both S- and R-isorobinals exhibited maximum activity at the same dose of 1 and 10 ng with a convex dose–response relationship. Amounts of S-isorobinal were determined to be 11.7 ± 1.0 ng per female and 6.4 ± 1.3 ng per male by GLC. This is the second example of two pheromones (the alarm pheromone neryl formate, and the sex pheromone S-isorobinal) demonstrated to be components of the same opisthonotal gland secretion.Chemical ecology of astigmatid mites. LXXVIII     

Evolutionary trends in the male pheromone systems of arctiid moths: evidence from studies of courtship in Phragmatobia fuliginosa and Pyrrharctia isabella (Lepidoptera: Arctiidae)

Male Phragmatobia fuliginosa and Pyrrharctia Isabella evert tubular abdominal scent-organs (coremata: during courtship. The coremata secrete a pheromone that is derived from pyrrolizidine alkaloids (PAs) obtained during larval feeding. Field-collected males vary widely in the amount of pheromone they possess. The courtship behaviour of these species was studied to determine whether this variation among males serves as a basis for mate choice by females, in a wind-tunnel a male approaches a pheromone-releasing female from downwind with his coremata everted in flight. A female perceiving the pheromone responds by fluttering her wings and emitting a clicking sound. This response did not occur in all courtships, and successful copulation was not dependent on its occurrence. Males denied access as larvae to the PA-precursors of the corematal pheromone (PA-denicd males' mated as rapidly as males allowed access to pheromone precursor (PA-supplied males). Moreover, antennectomized females mated as rapidly as normal females. Comparative analyses of transitional probabilities indicated no differences among courtships involving ! I': PA-denicd males and normal females, (II) PA-supplied males and normal females, or antennectomized females and normal males of unspecified feeding history. Field observations of courtship interactions between laboratory-reared females and wild males indicated that males having little or no pheromone succeed in mating in a natural setting as do males having a relativelv large amount of pheromone. It is hypothesized that the failure of female Ph. fuliginosa and Py, Isabella to enforce the display of PA-derived pheromone is related to an cvolutionarv trend away from an ancestral larval host-range restricted to PA-containing plants toward the polyphagv shown by manv temperate and arctic arctiids in the lineage (subfamily Arctiinae: tribe Arctiini) to which Ph. fuliginosa and Py. Isabella belong. Parallels in other moth groups are cited to support the notion that a plesiomorphic courtship pheromone system could persist in a vestigial state, despite the loss of its adaptive raison dêtre.     

Modulatory role of testosterone in alarm pheromone release by male rats

An alarm pheromone released from stressed conspecifics evokes behavioral and autonomic responses in rats. We have previously reported that male Wistar rats show behavioral changes including increased sniffing, walking and rearing, and decreased resting as well as exaggerated response of body temperature to a novel environment [known as stress-induced hyperthermia (SIH)] when they are exposed to an alarm pheromone released from other male rats receiving foot shocks. The purpose of the present study was to examine the role of testosterone in the production and release of the alarm pheromone using these behavioral and autonomic responses in recipient rats. Three groups of alarm pheromone donors were presented, namely, intact males, castrated males, and testosterone-implanted castrated males. The effects of the alarm pheromone on the autonomic responses did not differ among the three groups, regardless of the donor's steroidal milieu, whereas behavioral responses were altered by castrating the donor males and the effects were restored by testosterone implantation. These results suggest that the alarm pheromone released from stressed male rats can be classified into at least two categories according to the androgen dependency of their production and/or release.     

Effect of resistance to Bacillus thuringiensis cotton on pink bollworm (Lepidoptera: Gelechiidae) response to sex pheromone

Fitness costs associated with resistance to transgenic crops producing toxins from Bacillus thuringiensis (Bt) could reduce male response to pheromone traps. Such costs would cause underestimation of resistance frequency if monitoring was based on analysis of males caught in pheromone traps. To develop a DNA-based resistance monitoring program for pink bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae), we compared the response to pheromone traps of males with and without cadherin alleles associated with resistance to Bt cotton (Gossypium hirsutum L.). When irradiated males from two hybrid laboratory strains with an intermediate frequency of resistance alleles were released in large field cages, the probability of capture in pheromone traps was not lower for males with resistance alleles than for males without resistance alleles. These results suggest that analysis of trapped males would not underestimate the frequency of resistance. As the time males spent in traps in the field increased from 3 to 15 d, the success of DNA amplification declined from 100 to 30%. Thus, the efficiency of a DNA-based resistance monitoring program would be improved by analyzing males remaining in traps for 3 d or less.     

Assortative Mating in Two Pheromone Strains of the Cabbage Looper Moth, Trichoplusia ni

The evolution of animal communication systems is an integral part of speciation. In moths, species specificity of the communication channel is largely a result of unique sex pheromone blends produced by females and corresponding specificity of male behavioral response. Insights into the process of speciation may result from studies of pheromone strains within a species in which reproductive isolation is not complete. Toward this end we investigated assortative mating based on female pheromone phenotypes and male response specificity between mutant and normal colonies of the cabbage looper moth, Trichoplusia ni. There was no evidence of assortative mating in small cages in which the density of moths was high. In larger cages with lower densities of moths, assortative mating was evident. In these larger cages, matings between normal males and normal females and mutant males and mutant females were more frequent than interstrain matings. Wind tunnel tests indicated that normal males responded preferentially to pheromone released by normal females, whereas mutant males did not discriminate between normal and mutant pheromone blends. In large field cages, pheromone traps baited with normal females caught equal numbers of mutant and normal males, while pheromone traps baited with mutant females caught primarily mutant males. The overall pattern of assortative mating could be explained primarily based on the normal males' preference for the pheromone blend released by normal females.     

溴氰菊酯对亚洲玉米螟雄蛾感受雌性信息素的影响

为了探索溴氰菊醋对亚洲玉米螟雄蛾感受雌性信息素的影响,本文运用触角电位仪和风洞装置对亚洲玉米螟雄蛾进行了电生理和行为反应的测试．结果表明,处理雄蛾对不同比例雌性信息素的触角电位反应分别在E／Z;1／9、5／5和9／1处出现峰值,与对照相比无显著改变,但反应幅度为0．25—0．45mV,比对照下降0．15—0．35mV．对不同剂量的性信息素,引起可见触角电位反应的低限阈值为1ng,饱和反应剂量为10000ng,但反应幅度亦下降0．1—0．5mV,说明溴氰菊酯主要是影响雄蛾周缘感受系统的敏感性．但在风洞测试中,雄蛾除在反应率上比对照明显降低外,其峰值感受比例从E／Z＝1／1漂移到7／3以上．雄蛾对雌性信息素的低限反应剂量也从10ng漂移到100ng,并且高限反应剂量也从100000ng降低到50000ng,使有效作用剂量范围缩小．这说明溴氰菊酯对雄蛾的行为反应有较大影响,不仅使雄蛾对性信息素感受的敏感性降低,也影响到其感受的专化性。     

Factors affecting pheromone secretion and oviposition by fertilized females of Culicoides nubeculosus (Diptera: Ceratopogonidae)

The effect of age and a blood meal on pheromone secretion by virgin and fertilized females of Culicoides nubeculosus was studied. In virgin females, the secretion varies in relation to age, the blood meal, and oviposition. In fertilized females, rate of pheromone secretion is very low after fertilization and does not seem to vary subsequently in relation to the above factors. Mating was found to accelerate oviposition. The role of seminal fluid in the decrease in rate of pheromone secretion by fertilized females is discussed.