Antagonists to sex pheromones of the American cockroach

• 1.1. Considering the structures of periplanones A (1) and B (2) (sex pheromones of the American cockroach), derivatives of germacrene D (3) were prepared in order to find antagonists to the pheromones.
• 2.2. A new sex pheromone mimic (7) was found in the derivatives. Among pheromonally inactive derivatives, compounds 5 and 6 were found as a specific antagonist of 1 and a non-specific antagonist of 1 and 2, respectively.
• 3.3. In the DS-EAG experiment, 5 was revealed to participate specifically in the periplanone A receptor and to inhibit further participation of 1 in the receptor.

     

Electroantennogram responses to the sex pheromone and other odours in the American cockroach

Electroantennogram responses of adult American cockroaches were recorded for the sex pheromone and 30 kinds of monoterpenoids. Strong responses to the sex pheromone were obtained from the antennae of male adults, but not from females. The compounds possessing a hydroxyl or carbonyl group produced significant EAG responses in the antennae. Bornyl acetate, however, was an exception and gave strong responses in both male and female antennae. There was basically no difference between the antennal responsiveness to monoterpenoids tested in both sexes.     

Electroantennogram responses of the American cockroach to germacrene D sex pheromone mimic

Electroantennogram responses of adult American cockroaches were recorded from the sex pheromone mimic, germacrene D, and its related analogs. Germacrene D stimulated male antennae much greater than females, whereas other compounds produced significant responses of similar intensity with both male and female antennae. In the biological assay, only germacrene D induced the typical sexual behavior of males. The bioassay results imply that the conjugated system and isopropyl group of germacrene D are necessary chemical moieties for the sexual response in male cockroaches.     

Olfactory receptor responses to sex pheromone components in the redbanded leafroller moth

Electrical responses of single olfactory receptor neurons of the male redbanded leafroller moth were elicited by each of the principle components of the sex pheromone and six other behaviorally active compounds. Response frequencies to equal intensities of each of these compounds and changes in response frequency with increasing amounts of any one compound, varied from receptor to receptor. These differences in response characteristics appear to be due to factors intrinsic to the olfactory recptor neuron and not to factors external to it. The encoding of odor quality by these receptor neurons cannot be in the simple presence or absence of activity in any one of them. Rather, odor quality may be encoded by the pattern of activity which invariably arises across an ensemble of receptor neurons, each having its own distribution of sensitivities.     

Cereal aphid responses to sex pheromones and host-plant odours in the laboratory

Abstract. The movement of Sitobion fragariae (Wlk.) (Homoptera: Aphididae) males towards odours from conspecific sexual females (oviparae) and the aphid sex pheromone component (4a S ,7 S ,7a R )-nepetalactone were demonstrated in a linear-track olfactometer. Males of the closely related Sitobion avenae (Fab.) were attracted to odours from conspecific oviparae and also oviparae of S. fragariae. These results were consistent with the recent identification of this nepetalactone isomer as the major component of the sex pheromone in these species. Males of S.fragariae were not significantly attracted to oviparae of S.avenae. indicating some qualitative or quantitative difference in the pheromones of the two species. Males did not respond to the related (1R,4aS,7S,7aR)-nepetalactol or to host-plant odours. Gynoparae of these species moved towards the nepetalactone and also to host-plant odours. A combination of both stimuli was more attractive than plant odour alone. Gynoparae of S.fragariae also responded significantly to the combined treatment when this was tested against the nepetalactone.     

Temperature-mediated sex pheromone production and response of the American cockroach

Temperature affects the production of and response to sex pheromone by the American cockroach. Female sex-pheromone production is directly related to acclimation temperature and rapidly decreases 1 week after acclimation to lower temperatures. Production decreases slightly between weeks 1 and 2 and remains constant thereafter. Phermone-release rates are not affected by substrate temperature. Male response to a 1 ♀-equivalent hr pheromone dose is also temperature dependent. Maximal response was obtained at 26.7°C. Acclimated males were able to perceive pheromone (EAG technique) and capable of movement at lower temperatures (10°C), suggesting central nervous system inhibition.     

Pheromone-stimulated locomotory and orientation responses in the American cockroach

Males of Periplaneta americana respond to the sex pheromone secreted by females with increased locomotion and positive chemo-orientation. Both sexes orient toward aggregation pheromone without an increase in locomotion. Immediately following removal of one antenna males exhibit ‘circus’ movements, but after 2 days orient toward pheromones; a bi-modal mechanism of chemo-orientation is proposed. Cockroaches turn away from air currents, but orient toward air currents carrying sex or aggregation pheromone, suggesting the possibility of up-wind orientation. Antennae deflect upward and outward when pheromone is first perceived; the head then moves toward the pheromone source. Following removal of one antenna, the pattern of head and antennal movement changes in a manner which enhances the sweeping of the intact antenna.     

Sex pheromones of the yeast Hansenula wingei and their relationship to sex pheromones in Saccharomyces cerevisiae and Saccharomyces kluyveri

The yeast, Hansenula wingei has two mating types designated 5 and 21. Cells of each mating type were found to produce mating type-specific sex pheromone which induces sexual agglutinability of the opposite mating type. Crude fractions of these pheromones were prepared by using an Amberlite CG 50 (H⁺ type) column. The agglutinability-inducing action of the pheromones required glucose as carbon source, but no external nitrogen source. The action of the pheromones was inhibited by 5 g/ml cycloheximide. The optimum pH for the pheromone action was 4.0. Pheromones of Saccharomyces cerevisiae and Saccharomyces kluyveri induced sexual agglutinability of 5 mating type cells but did not that of 21 mating type cells. a Pheromones of the Saccharomyces yeasts had no effect on both 5 and 21 mating type cells. The sex pheromones of H. wingei had no effect on the sexual agglutinability of inducible a cells of S. cerevisiae. From the experimental results obtained so far, we propose to call 5 and 21 mating types in H. wingei a and mating types, respectively.     

Chemical characterization of sex pheromones and their biosynthetic intermediates

One of the major problems in studies on olfaction is that ofdefining a relevant stimulus. In the context of insect sex pheromones,this problem is that of defining a phermone component. In recentyears, a wealth of information has been obtained on the biosyntheticpathways by which sex pheromones are produced. Several ruleshave emerged that have allowed generalizations concerning theevolution of phermone blends within taxonomic groups. Severaladvances in analytical techniques have allowed precise and reliableidentification of sex pheromones With the appropriate technologyand the knowledge obtained from comparative studies betweentaxonomic groups, it is now possible to determine with a highdegree of accuracy what the pheromone for a species is, andthus to define precisely the relevant stimulus for behavioraland electrophysical studies.     

Orientation to sex pheromone in the American cockroach: Analysis of chemo-orientation mechanisms

Male Periplaneta americana were photographed in a 2.4 m diameter arena containing a female sex pheromone source in the centre. Orientation pathways were digitized and analysed with regard to chemo-orientation mechanisms employed. Indirect components of chemo-orientation include arrestment near the pheromone source owing to an increase in turning rate and decrease in rate of locomotion, and zig-zag motor patterns that facilitate localization of the source. Most males were successful in locating the source if they moved to within 30 cm. Direct components of chemo-orientation include looping and relatively sharp correcting turns.No significant differences in orientation were observed between intact and unilaterally-antennectomized males, except that correcting turns close to the pheromone source were significantly less precise in males with one antenna. These results indicate that males with two antennae have an advantage over males with one antenna in being able to employ simultaneous information processing close to the pheromone source. Males with crossed antennae were unable to locate the pheromone source, suggesting that the fixed position of their antennae interfered with sensory information input.     

Olfactory receptor cell responses of pigeon to some odors

A preparation has been developed in the pigeon which allows recording of the electrical activity from an olfactory nerve twig containing the nonmyelinated axons of a small group of olfactory receptor cells. The pigeon's response to n-amylacetate is vigorous and stable, like that of other air-breathing animals. Responses in the olfactory receptor cells in the pigeon increased in magnitude with increase in the odor concentration. An olfactory nerve twig produced a different magnitude of responses to the various odor stimuli. When an odor stimulation was applied to the olfactory mucosa, the two different olfactory nerve twigs which were separated from the same olfactory nerve bundle produced a different magnitude of responses. The differences may be dependent on several factors.     

斜纹夜蛾触角叶神经元及其对植物气味和性信息素的反应

【目的】探索斜纹夜蛾Spodoptera litura触角叶结构及其神经元对植物气味和性信息素的神经识别机制。【方法】利用共聚焦激光技术扫描斜纹夜蛾成虫触角叶结构,同时采用多通道电生理技术(multi-unit recording,MR)记录斜纹夜蛾触角叶对6种寄主植物气味化合物(苯甲醛、苯甲醇、苯乙醛、水杨醛、乙酸叶醇酯和己烯醛)及性信息素顺9反11十四碳二烯乙酸酯和顺9反12十四碳二烯乙酸酯的反应;并在风洞中测定分析斜纹夜蛾对上述化合物的定向行为反应。【结果】共聚焦激光扫描结果显示,雄性和雌性斜纹夜蛾触角叶内分别密集地分布有67和66个神经纤维球;而雌性斜纹夜蛾触角叶内的纤维球总体积和平均体积都高于雄性。负责识别和追踪性信息素的扩大型纤维球复合体(macroglomerular complex,MGC)只在雄性斜纹夜蛾触角叶内发现。MR试验结果显示斜纹夜蛾触角叶内神经元具有3种自发放电模式:稀疏放电(不规则的放电频率)、温和放电(宽而慢的放电频率)和密集放电(暴发性的放电频率)。同时,斜纹夜蛾触角叶神经元对所有刺激的气味表现出3种反应类型:兴奋性、抑制性和无反应。神经元对气味的兴奋性和抑制性反应以及无反应取决于刺激化合物的结构和浓度。雌虫的触角叶神经元对性信息素和单一的植物气味表现出很小的反应,而雄虫对两种性信息素以及苯甲醛、苯甲醇、苯乙醛和水杨醛具有很强的兴奋性反应。斜纹夜蛾风洞试验也显示绝大部分的斜纹夜蛾雄虫都选择停留在性信息素和芳香族化合物上,这与MR的结果一致。【结论】神经元的反应强度和刺激化合物浓度之间的关系根据不同的神经元和刺激化合物而有所不同。在测试的浓度范围内,雄虫触角叶神经元对性信息素的反应强度随着浓度的增加而加强,但是除乙酸叶醇酯外,对其他植物气味的反应强度在测试的浓度范围内没有显著的变化。     

Intracellular responses of antennal chordotonal sensilla of the American cockroach

The responses of mechanoreceptor neurons in the antennal chordotonal organ have been examined in cockroaches by intracellular recording methods. The chordotonal organ was mechanically stimulated by sinusoidal movement of the flagellum. Stimulus frequencies were varied between 0.5 and 150 Hz. Receptor neurons responded with spike discharges to mechanical stimulation, and were classed into two groups from plots of their average spike frequencies against stimulus frequency. Neurons in one group responded to stimulation over a wide frequency range (from 0.5 to 150 Hz), whereas those in a second group were tuned to higher frequency stimuli. The peak stimulus frequency at which receptor neurons showed maximum responses differed from cell to cell. Some had a peak response at a stimulus frequency given in the present study (from 0.5 to 150 Hz), whereas others were assumed to have peak responses beyond the highest stimulus frequency examined. The timing for the initiation of spikes or of a burst of spikes plotted against each stimulus cycle revealed that spike generation was phase-locked in most cells. Some cells showed phase-independent discharges to stimulation at lower frequency, but increasing stimulus frequencies spike initiation began to assemble at a given phase of the stimulus cycle. The response patterns observed are discussed in relation to the primary process of mechanoreception of the chordotonal organ.     

Electroantennogram responses of two tortricid moths using two-component sex pheromones

Antennal responses of male Adoxophyes orana and Clepsis spectrana to their two pheromone components, cis-9- and cis-11-tetradecenyl acetate (tda) were studied. Responses to a dilution series of the components alone and in five mixture ratios were recorded. The main pheromone component for A. orana (cis-9-tda) and for C. spectrana (cis-11-tda) gave the highest electroantennogram (EAG) responses, respectively, but mixtures corresponding to the optimum field attracting ratios for each species elicited higher responses than the separate components.The geometrical isomers, trans-9- and trans-11-tda, which inhibit male A. orana response in the field, do not appear to give an additive EAG response when mixed with the pheromone components.     

Summer diapause and nymphal growth in a subtropical cockroach: response to changing photoperiod

Abstract.  The effects of photoperiod on nymphal growth and adult reproduction were investigated in a small cockroach, Margattea satsumana, living on the subtropical, Hachijo island (33°N), Japan. Nymphal development is slow under constant photoperiods at 25 °C. The shortest mean duration of nymphal development (176 days) is observed at LD 14 : 10 h, followed by LD 12 : 12 h (221 days) and LD 16 : 8 h (309 days). Nymphal development is further prolonged when the nymphs are transferred from LD 12 : 12 to LD 16 : 8 h at 90 days after hatching. However, rapid and synchronized development is observed when nymphs were transferred in the opposite direction. A decreased change in photoperiod from LD 14 : 10 to LD 12 : 12 h also reduces the duration of nymphal development, and this cannot be explained by the results obtained at constant photoperiods. Similarly, nymphs reared at LD 16 : 8 h during the first 60 days mature more rapidly when transferred to LD 12 : 12 h than when transferred to LD 14 : 10 h. The developmental suppression induced by long days may represent a form of summer diapause that is terminated rapidly by short days. Based on these observations and field-census data, it is suggested that this cockroach has a univoltine life cycle overwintering as nondiapause adults, and that this life cycle is stabilized by the response to changing photoperiod.     

Ostrinia spp. in Japan: their host plants and sex pheromones

To contribute to the understanding of the genus Ostrinia (Lepidoptera; Pyralidae) in Japan, we collected larvae of Ostrinia spp. from known host plants and plants not recorded as hosts, and we examined the morphology and sex pheromones of the adults obtained. Consequently, the host plant ranges of the 7 Ostrinia spp. in Japan were clarified, and the sex pheromones of the 5 species O. scapulalis, O. zealis, O. zaguliaevi, O. palustralis and O. latipennis were identified in addition to that of the Asian corn borer O. furnacalis. The phylogenetic relationships of Japanese Ostrinia spp., with reference to the European corn borer O. nubilalis, are discussed based on these findings and results of molecular phylogenetic analyses.     

Development-activity relationships in nymphal corpora allata of the cockroach, Diploptera punctata

Abstract. In females of Diploptera punctata the corpora allata undergo a gradual increase in volume during most of the second nymphal stadium. In the first half of the stadium, steady growth of the glands results from a progressive increase in the size of constituent cells. Late in the stadium, cell size declines but the volume of the glands continues to rise due to an increase in cell number. Changes in cell size during the stadium displayed a distinct pattern in relation to Juvenile Hormone (JH) synthesis. Both cell size and activity increased during the first two-thirds of the stadium, peaked early in the last third of the stadium, and decreased before the moult. The rise in cell numbers late in the stadium corresponded to a wave of cellular mitosis and occurred after a steep decline in the rate of JH biosynthesis. Exposure of late second instars to fenoxycarb. a JH analogue, depressed mitosis significantly, suggesting autocrine regulation of cell proliferation in the corpora allata. Possible mechanisms modulating sequential cycles of growth and atrophy of cells and cell proliferation in these glands are discussed in relation to temporal patterns of JH and ecdysteroid titres in nymphs.     

杀蟑胶饵室内药效及德国小蠊对氟虫腈抗药性研究

【目的】本文通过测定杀蟑胶饵对德国小蠊Blattellagermanica(L.)和美洲大蠊Periplaneta americana (L.)的致死效果,以及德国小蠊对杀虫剂氟虫腈的抗性,从而为胶饵选择和蟑螂的化学防治提供参考。【方法】用饲喂法在实验室测定了7种国产杀蟑胶饵及5种美国产杀蟑胶饵或毒饵站对德国小蠊的致死效果,5种国产蟑螂胶饵对美洲大蠊的致死效果,以及对5种国产蟑螂胶饵陈化1个月后对德国小蠊的致死效果。并采用点滴法测定了两个德国小蠊野外品系对氟虫腈的抗性。【结果】7种中国产胶饵中,5种对德国小蠊抗性和非抗性品系在第7天的校正死亡率高于91%。其中韩世和克贝特对德国小蠊的药效显著慢于绿叶、宏宇洁和优士。绿叶、宏宇洁和优士对美洲大蠊在第7天的校正死亡率均高于89%。陈化1个月后的胶饵只有克贝特对蟑螂的致死率有较大降低。美国产胶饵或毒饵站对德国小蠊的致死率均大于82%。点滴法抗性测定结果显示德国小蠊的两个野外品系(Cincy,Irvington)对氟虫腈生理抗性指数分别是4.3和115.1。【结论】不同胶饵对德国小蠊和美洲大蠊的致死效果有明显差异。尽管德国小蠊Irvington品系对氟虫腈表现为高抗性,含0.05%氟虫腈的胶饵仍然对它有效。