			Home About us Contact

Virgin Females (virgin + female)

Distribution by Scientific Domains

Life Sciences	78%
Chemistry	12%

Selected Abstracts

Expression of GABAB Receptors in Magnocellular Neurosecretory Cells of Male, Virgin Female and Lactating Rats

JOURNAL OF NEUROENDOCRINOLOGY, Issue 7 2005
D. S. Richards
Abstract GABA is one of the key neurotransmitters that regulate the firing activity of neurones in the supraoptic (SON) and paraventricular (PVN) nuclei. In the present study, we used immunohistochemical techniques to study the distribution and subcellular localisation of metabotropic GABAB receptors in magnocellular neurones in the SON and PVN. Robust GABAB receptor immunoreactivity (GABABR; both subunit 1 and subunit 2 of the heterodimer), was observed in the SON and PVN. At the light microcope level, GABABR immonoreactivity displayed a clustered pattern localised both intracytoplasmically and at the plasma membrane. Densitometry analysis indicated that GABABR immunoreactivity was significantly more intense in vasopressin cells than in oxytocin cells, both in male, virgin female and lactating rats, and was denser in males than in virgin females. Light and electron microscope studies indicated that cytoplasmic GABABR was localised in various organelles, including the Golgi, early endosomes and lysosomes, suggesting the cycling of the receptor within the endocytic and trafficking pathways. Some smaller clusters at the level of the cell plasma membrane were apposed to glutamic acid decarboxylase 67 immunoreactive boutons, and appeared to be colocalised with gephyrin, a constituent protein of the postsynaptic density at inhibitory synapses. The presence of GABABR immunoreactivity at synaptic and extrasynaptic sites was supported by electron microscopy. These results provide anatomical evidence for the expression of postsynaptic GABAB receptors in magnocellular neurosecretory cells. [source]

Experience Plays a Role in Female Preference for Symmetry in the Swordtail Fish Xiphophorus malinche

ETHOLOGY, Issue 9 2009
M. Scarlett Tudor
Variation in female mating preferences was previously detected in wild-caught Xiphophorus cortezi and Xiphophorus malinche females: smaller (presumed younger) females preferred symmetrical males, while larger (presumed older) females preferred asymmetrical males. We examined the influence of experience on this variation in female preference by determining if X. malinche females would express a preference for symmetry as virgins, shift their preferences for bar symmetry as they got larger (older) and if experience with males of different bar number symmetry could explain the variation in female preference previously detected. Virgin females exhibited no preference for vertical bar number symmetry when tested in the young- or old-age classes. However, young virgins spent more time with the opposite treatment in the second when compared with first test, indicating an ability to detect the difference between symmetry and asymmetry, and potentially a preference to mate with multiple males. When females were reared in one of three treatments, housed with symmetrical, barless or both symmetrical and asymmetrical males, we detected both a treatment and tank effect on strength of preference for symmetry, suggesting that barring pattern and some other aspect of the social environment influenced the development of this mating preference. Finally, we detected no effect of age class on mean strength of preference for symmetry; however, there was a statistically different relationship between female size and strength of preference for symmetry across the two age classes, suggesting that the preference function for symmetry may not be linear in relation to female size. [source]

Courtship and copulation, but not ejaculates, reduce the longevity of female field crickets (Gryllus bimaculatus)

JOURNAL OF ZOOLOGY, Issue 4 2006
P. W. Bateman
Abstract Females of many taxa incur fitness costs from male sexual coercion and harassment leading to mating. Although male crickets cannot force copulations on females, female Gryllus bimaculatus in this study incurred significant reductions in longevity through being exposed to different levels of male courtship. Virgin females kept in isolation had the longest life spans. Reductions in longevity applied to females in sensory contact with males (without the opportunity to mate), females that courted and mated and females that mated but with fertilization being prevented. Females also incurred significant reductions in longevity when kept with other females, which may have been due to high levels of cannibalism. Consistent with previous studies, females appeared to incur no cost to longevity from receiving sperm or seminal fluid. It is known that female G. bimaculatus benefit genetically from multiple mating. However, this benefit could possibly be offset by the negative effect that male courtship and mating behaviour has on female longevity. [source]

Spatial patterns, temporal variability, and the role of multi-nest colonies in a monogynous Spanish desert ant

ECOLOGICAL ENTOMOLOGY, Issue 1 2002
Xim Cerdá
Abstract 1.,The colonies of the Spanish desert ant Cataglyphis iberica are polydomous. This study describes the temporal and spatial patterns of the polydomy in this species at two different sites, and presents analyses of its role in reducing the attacks of the queen over sexual brood, and in allowing better habitat exploitation. 2. The spatial distribution of nests was clumped while colonies were distributed randomly. Mean nearest neighbour distance ranged from 3.4 to 7.0 m for nests and from 12.3 to 14.1 m for colonies. Distance of foragers searching for food varied among nests: mean values were between 6.1 and 12.6 m. 3. At both sites, the maximum number of nests per colony occurred in summer, during the maximum activity period of the species. Colonies regrouped at the end of this period but overwintered in several nests. 4. Nest renewal in C. iberica colonies was high and showed great temporal variability: nests changed (open, close, re-open) continuously through the activity season and/or among years. The lifetime of up to 55% of nests was only 1,3 months. 5. Polydomy in C. iberica might decrease the interactions between the queen and the sexual brood. In all colonies excavated just before the mating period, the nest containing the queen did not contain any virgin female. Females were in the queenless nests of the colony. 6. The results also suggest that polydomous C. iberica colonies may enhance habitat exploitation because foraging activity per colony increases with nest number. The relationship between total prey input and foraging efficiency and number of nests per colony attains a plateau or even decreases after a certain colony size (four to six nests). This value agrees with the observed mean number of nests per colony in C. iberica. [source]

Expression of GABAB Receptors in Magnocellular Neurosecretory Cells of Male, Virgin Female and Lactating Rats

Pregnancy and lactation have anti-obesity and anti-diabetic effects in Ay/a mice

ACTA PHYSIOLOGICA, Issue 2 2010
E. N. Makarova
Abstract Aim:, Dominant ,yellow' mutation at the mouse agouti locus (Ay) results in obesity. Pregnancy and lactation are characterized by large energy demand. The aim of this study was to investigate whether obesity would develop in pregnant and suckling Ay mice. Methods:, Body weight and food intake in pregnancy, lactation, and after weaning, plasma leptin, insulin, corticosterone and blood glucose concentrations on days 7, 13 and 18 of pregnancy, days 1, 10, 21 and 80 postpartum, glucose and insulin tolerance on pregnancy days 7 and 18 were measured in C57Bl/6J mice of a/a (normal metabolism) and Ay/a genotypes. The same parameters were also measured in age-matched virgin females. Results:, Virgin Ay/a females exhibited hyperphagia, enhanced body weight, glucose intolerance and normal blood parameters at the mating age. With age, they developed obesity, hyperleptinaemia, hyperinsulinaemia and hyperglycaemia. Obesity did not develop in mated Ay/a mice; during suckling, they had equal food intake and body weight as a/a mice. During pregnancy, glucose tolerance was enhanced in Ay/a mice and became equal in both genotypes. In both genotypes, concentrations of hormones increased, and glucose decreased from pregnancy day 7 to day 18 and returned to normal values after parturition. Ay/a mice did not differ from a/a in corticosterone, insulin and glucose levels during pregnancy and lactation, in leptin levels during suckling; however, Ay/a mice had two times higher leptin levels than a/a during pregnancy. After weaning, Ay/a mice began to eat and weigh more than a/a exhibiting normal metabolic parameters for 50 days. Conclusion:, Pregnancy and lactation retard obesity and diabetes development in Ay mice. [source]

Differential roles of two major brain structures, mushroom bodies and central complex, for Drosophila male courtship behavior

DEVELOPMENTAL NEUROBIOLOGY, Issue 8 2006
Takaomi Sakai
Abstract Drosophila male courtship is a complex and robust behavior, the potential for which is genetically built into specific neural circuits in the central nervous system. Previous studies using male-female mosaics and the flies with defects in particular brain structures implicated the critical central regions involved in male courtship behavior. However, their acute physiological roles in courtship regulation still largely remain unknown. Using the temperature-sensitive Dynamin mutation, shibirets1, here we demonstrate the significance of two major brain structures, the mushroom bodies and the central complex, in experience-independent aspects of male courtship. We show that blocking of synaptic transmission in the mushroom body intrinsic neurons significantly delays courtship initiation and reduces the courtship activity by shortening the courtship bout length when virgin females are used as a sexual target. Interestingly, however, the same treatment affects neither initiation nor maintenance of courtship toward young males that release courtship-stimulating pheromones different from those of virgin females. In contrast, blocking of synaptic transmission in a central complex substructure, the fan-shaped body, slightly but significantly reduces courtship activity toward both virgin females and young males with little effect on courtship initiation. Taken together, our results indicate that the neuronal activity in the mushroom bodies plays an important role in responding to female-specific sex pheromones that stimulate initiation and maintenance of male courtship behavior, whereas the fan-shaped body neurons are involved in maintenance of male courtship regardless of the nature of courtship-stimulating cues. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source]

Behavioral evidence for a female-produced sex attractant in Diaphorina citri

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2008
Erik J. Wenninger
Abstract Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is an important worldwide pest of citrus. It vectors three phloem-restricted bacteria in the genus Candidatus Liberibacter that cause huanglongbing (citrus greening disease). Studies were conducted to examine the behavioral responses of male and female D. citri to conspecifics of the same and opposite sex, with and without associated citrus host plants, in both open-air arena choice assays and Y-tube olfactometer assays. Virgin and mated male D. citri colonized citrus plants that were currently or had been previously colonized by virgin or mated female D. citri in greater numbers than control plants without females. However, males or females did not accumulate more on plants colonized by conspecifics of the same sex compared to uninfested plants, and females showed no preference for plants pre-infested with males compared with uninfested controls. In complementary Y-tube olfactometer assays, virgin and mated males chose arms with odor sources from mated females compared with blank controls in the absence of associated citrus host plant volatiles. In both behavioral assays, mated female D. citri appeared more attractive than virgin females. The vibrational calling behavior of male D. citri was reduced when males were challenged by the odors of conspecific mated females relative to when males were challenged by the odor of other males. Collectively, our results provide behavioral evidence for a female-produced volatile sex attractant pheromone in D. citri. Future identification and synthesis of a sex attractant pheromone will be an important contribution to current monitoring and management practices for D. citri. [source]

Whole body extract of Mediterranean fruit fly males elicits high attraction in virgin females

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2008
Vassilis G. Mavraganis
Abstract The search for effective female attractants emanating from the host or body of fruit flies has been an area of intensive research for over three decades. In the present study, bodies of male Mediterranean fruit flies, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), were extracted with diethyl ether or methanol and subjected to gas chromatography,mass spectrometry. Analysis revealed substantial qualitative and quantitative differences between males from a laboratory culture and wild males captured alive in an orchard. Most notably, the hydrocarbon sesquiterpene (±)-,-copaene, which is known to be involved in the sexual behaviour of the species, was found in substantial amounts in wild males, but was not detected in laboratory males. In laboratory tests, 15 laboratory or wild male equivalents of diethyl ether extracts or combined diethyl ether and methanol extracts, or, to a lesser extent, methanol extracts alone, were found to attract virgin females. In a citrus orchard, traps baited with combined diethyl ether and methanol extracts of wild males attracted significantly more virgin females than traps baited with various doses of pyranone or blends of other compounds identified in the extracts or reported in the literature, such as ethyl acetate, ethyl-(E)-3-octenoate, and 1-pyrroline. Traps baited with blends of compounds, however, displayed substantial attractiveness compared to control (non-baited) traps. These results are important for better understanding the mating system of C. capitata as well as for further improving existing monitoring and control systems. [source]

Factors influencing the effectiveness of an attracticide formulation against the Oriental fruit moth, Grapholita molesta

ENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 2 2004
Maya L. Evenden
Abstract An attracticide formulation, LastCallÔOFM, was tested against the Oriental fruit moth Grapholita molesta (Busck) (Lepidoptera: Tortricidae) in replicated small plot field trials in apple, Malus domestica (Borkhausen), orchards in South-eastern Pennsylvania, USA. Attracticide treatments were applied using a calibrated hand pump, and treated plots were compared to similar untreated plots. Male moth activity was monitored using virgin female-baited traps, and the potential for reduction in mating activity was assessed using sentinel virgin females. A comparison of application rates showed that 1500 droplets per ha of the attracticide formulation was as effective as 3000 droplets per ha, and both application rates reduced captures in synthetic pheromone-baited traps for prolonged periods. Droplets placed either at high or low positions within the canopy significantly reduced trap capture and mating with sentinel females. In addition, the only sentinel females that mated in the treated plots were located in the untreated portion of the tree canopy. Mate finding behaviour was equally disrupted by formulations with and without insecticide. Therefore, under the test conditions, the mechanism by which the attracticide formulation worked was by disruption of male orientation, and not by the removal of males due to insecticide poisoning. Two field cage experiments tested the impact of population density on the competitiveness of the attracticide formulation compared to virgin females. A significant proportion of males were captured in female-baited traps at the highest female-to-droplet ratio tested. Equal proportions of males were captured in attracticide-baited traps at male moth densities of 10, 20, 40, and 80 males per cage. These results clarify some of the factors influencing the effectiveness and possible mechanisms of an attracticide management tactic against the Oriental fruit moth. [source]

Accessory gland secretory proteins in relation to fitness parameters of Drosophila ananassae and D. varians

ENTOMOLOGICAL RESEARCH, Issue 5 2010
Raghavendra B. HIREMANI
Abstract Developmental morphometry, qualitative and quantitative analysis of the accessory gland secretory proteins, fecundity and productivity in relation to protein ejected during subsequent (first to fourth-time) matings have been studied in Drosophila ananassae Doleschall and Drosophila varians Bock. In both species, size and secretion of accessory glands increases from 1 to 8 days and the stored secretion ejected from males to the female genital tract during subsequent mating varies. The maximum number of eggs and flies are produced from the females mated with bachelor males and it is a minimum when virgin females are mated with fourth-time mated males. Sodium dodecylsulfate,polyacrylamide gel electrophoresis analysis of accessory gland secretory protein patterns and their glycosylation differs in both the species. Correlation coefficient analysis between gland size and quantity of secretion, percentage of secretory protein transferred per mating, and eggs and flies that emerged showed a highly significant, positive relationship. Among different matings, the number of eggs laid and flies that emerged per female between subsequent (first to fourth-time) matings of males was found to be highly significant and the difference between fecundity and productivity between the two species was highly significant. [source]

Male Performance and Body Size Affect Female Re-Mating Occurrence in the Orb-Web Spider Leucauge mariana (Araneae, Tetragnathidae)

ETHOLOGY, Issue 12 2009
Anita Aisenberg
Females can affect male probabilities of paternity success through behavioural, morphological and/or physiological processes occurring during or after copulation. These processes under female-control include the acceptance or rejection of mating attempts by subsequent males. Leucauge mariana is an orb weaving spider that shows male mate guarding of penultimate females, male,male competition on female webs and copulatory plugs, suggesting a polyandric mating system. The aim of the present study was to ascertain whether male behaviour during courtship and copulation in L. mariana relate with female re-mating decisions. Forty-three virgin females were exposed to up to three males until they mated. In 24 cases, the copulatory plug was absent after mating and females were exposed the next day to up to three other males. Eighteen females accepted a second mating. Relatively larger females were more receptive to second matings and were more likely to copulate if the second male was smaller. Longer duration of female tapping and abdominal bobbing during courtship, and first copulations with less short insertions and more flubs, were associated with increased female acceptance to second matings. The results indicate cryptic female choice on male courtship and copulatory performance and suggest female-control over the determination of male mating success in this spider species. [source]

Premating Avoidance of Inbreeding Absent in Female Guppies (Poecilia reticulata)

ETHOLOGY, Issue 7 2006
Åslaug Viken
The recognition and avoidance of kin during mating can be an important means of reducing the potential for inbreeding depression in offspring. We report here that premating mechanisms to avoid inbreeding, either innate or learnt through juvenile experience, are at best weak in female guppies (Poecilia reticulata). Guppies are small, ovoviviparous, neo-tropical freshwater fish, with a polygamous mating system where males actively court females and females are selective of their mates. In a series of mate-choice experiments, naïve, virgin females of the Quare River population in Trinidad were given a choice between a brother and a non-sib male from the same population. Initially, females were only provided olfactory cues upon which to base their choice and then subsequently both olfactory and visual cues. Despite the females displaying mate choice, we found no evidence of them discriminating between the male types in either experiment. There was thus no indication of inbreeding avoidance, suggesting that experiences after maturation or with mature males (e.g. rare male preference), dispersal and/or post-mating mechanisms may be evolutionarily more important avoidance mechanisms. [source]

Male Mate Choice in the Guppy (Poecilia reticulata): Do Males Prefer Larger Females as Mates?

ETHOLOGY, Issue 2 2004
Emily J. E. Herdman
Although females are the choosier sex in most species, male mate choice is expected to occur under certain conditions. Theoretically, males should prefer larger females as mates in species where female fecundity increases with body size. However, any fecundity-related benefits accruing to a male that has mated with a large female may be offset by an associated fitness cost of shared paternity if large females are more likely to be multiply mated than smaller females in nature. We tested the above hypothesis and assumption using the Trinidadian guppy (Poecilia reticulata) by behaviourally testing for male mate choice in the laboratory and by ascertaining (with the use of microsatellite DNA genotyping) patterns of male paternity in wild-caught females. We observed significant positive relationships between female body length and fecundity (brood size) and between body length and level of multiple paternity in the broods of females collected in the Quaré River, Trinidad. In laboratory tests, a preference for the larger of two simultaneously-presented virgin females was clearly expressed only when males were exposed to the full range of natural stimuli from the females, but not when they were limited to visual stimuli alone. However, as suggested by our multiple paternity data, males that choose to mate with large females may incur a larger potential cost of sperm competition and shared paternity compared with males that mate with smaller females on average. Our results thus suggest that male guppies originating from the Quaré River possess mating preferences for relatively large females, but that such preferences are expressed only when males can accurately assess the mating status of encountered females that differ in body size. [source]

EJACULATE DEPLETION PATTERNS EVOLVE IN RESPONSE TO EXPERIMENTAL MANIPULATION OF SEX RATIO IN DROSOPHILA MELANOGASTER

EVOLUTION, Issue 8 2007
Jon R. Linklater
We assessed the extent to which traits related to ejaculate investment have evolved in lines of Drosophila melanogaster that had an evolutionary history of maintenance at biased sex ratios. Measures of ejaculate investment were made in males that had been maintained at male-biased (MB) and female-biased (FB) adult sex ratios, in which levels of sperm competition were high and low, respectively. Theory predicts that when the risk of sperm competition is high and mating opportunities are rare (as they are for males in the MB populations), males should increase investment in their few matings. We therefore predicted that males from the MB lines would (1) exhibit increased investment in their first mating opportunities and (2) deplete their ejaculates at a faster rate when mating multiply, in comparison to FB males. To investigate these predictions we measured the single mating productivity of males from three replicates each of MB and FB lines mated to five wild-type virgin females in succession. In contrast to the first prediction, there was no evidence for differences in productivity between MB and FB line males in their first matings. The second prediction was upheld: mates of MB and FB males suffered increasingly reduced productivity with successive matings, but the decline was significantly more pronounced for MB than for FB males. There was a significant reduction in the size of the accessory glands and testes of males from the MB and FB regimes after five successive matings. However, the accessory glands, but not testes, of MB males became depleted at a significantly faster rate than those of FB males. The results show that male reproductive traits evolved in response to the level of sperm competition and suggest that the ability to maintain fertility over successive matings is associated with the rate of ejaculate, and particularly accessory gland, depletion. [source]

The sex-peptide DUP99B is expressed in the male ejaculatory duct and in the cardia of both sexes

FEBS JOURNAL, Issue 21 2003
Albana Rexhepaj
Mating elicits two postmating responses in many insect females: the egg laying rate increases and sexual receptivity is reduced. In Drosophila melanogaster, two peptides of the male genital tract, sex-peptide and DUP99B, elicit these postmating responses when injected into virgin females. Here we show that the gene encoding DUP99B is expressed in the male ejaculatory duct and in the cardia of both sexes. The DUP99B that is synthesized in the ejaculatory duct is transferred, during mating, into the female genital tract. Expression of the gene is first seen in a late pupal stage. Males containing an intact ejaculatory duct, but lacking accessory glands, initiate the two postmating responses in their female partners [Xue, L. & Noll, M. (2000) Proc. Natl Acad. Sci. USA97, 3272,3275]. Although such males synthesize DUP99B in wild-type quantities, they elicit only weak postmating responses in their mating partners. Males lacking the Dup99B gene elicit the two postmating responses to the same extent as wild-type males. These results suggest that both sex-peptide and DUP99B can elicit both responses in vivo. However, sex-peptide seems to play the major role in eliciting the postmating responses, while DUP99B may have specialized for other, as yet unknown, functions. [source]

Comparisons of calling behaviour of different geographical populations of Helicoverpa armigera

JOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2007
X.-C. Zhao
Abstract:, The cotton bollworm, Helicoverpa armigera, with worldwide distribution, evolves into different geotypes for adapting to the changes of geographical climates. Comparisons of calling behaviour of the insect collected from the temperate region in northern China (Beijing), the temperate region in north-western China (Kashi) and the tropical region in southern China (Haikou) were investigated in the laboratory as a first step to understanding the influence of reproductive behaviour on its population differentiation. There were more than 80% of virgin females of each population that showed calling behaviour. The age at which the moths of all three populations initiated calling varied significantly. The durations of calling in scotophase and the percentages of females calling also differed between populations. Only a few females of the Beijing and Haikou populations called in the first 2 h after the onset of scotophase, whereas many Kashi females called at this time. However, the main calling peak occurred during the second half of scotophase for all three populations. Females of the Beijing and Haikou populations exhibited similar calling onset times at the same age, whereas the Kashi females initiated calling significantly earlier than those of Beijing and Haikou from nights 3 to 7. The durations of each calling bout and the time spent by both Beijing and Haikou populations were similar to each other at the same age, but were significantly shorter than that of the Kashi population from nights 3 to 7. These results suggest that there are genetic variations not only in pre-period calling but also in the calling behaviour of H. armigera. [source]

Factors affecting the response of Ceutorhynchus assimilis Payk. (Col., Curculionidae) males to conspecific odour

JOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2001
F. Nazzi
The effect of post-emergence feeding on the response of Ceutorhynchus assimilis males to conspecific odour was studied using both laboratory-overwintered and field-collected weevils. The response of males to females at different times in the season was also investigated using field-collected weevils. Males did not respond to the odour of virgin females that were newly emerged from diapause. However, they showed a significant response to the odour of overwintered virgin females that had spent some days on flowering rape. The response of males to females appeared to decline as the season progressed. [source]

Pheromone blends and trap designs can affect catches of Sesamia nonagrioides Lef. (Lep., Noctuidae) males in maize fields

JOURNAL OF APPLIED ENTOMOLOGY, Issue 1-2 2001
A. Ameline
Among lepidopteran insects, the female-produced sex pheromones are the most widely used chemical stimuli for pest management by (i) mating disruption, and (ii) monitoring adult insect populations in agricultural crops. Sesamia nonagrioides is one of the main pests on maize crops around the Mediterranean area and monitoring adult populations with synthetic sex pheromone is of great interest. The technique used involved field trapping with synthetic pheromone blend. The reliability of the technique is directly related to the trap shape and pheromone blends. Universal Moth Trap® (UM trap, Biosyste,mes, France) and Service Régional de la Protection des Végétaux (SRPV) traps baited with either synthetic pheromone blend or virgin females were evaluated in two commercial maize fields (var.cecilia) (Belleserre, Tarn. France) to determine the potential use of synthetic lures in monitoring S. nonagrioides populations in maize field. The study showed that SRPV traps baited with synthetic pheromone blend caught significantly more S. nonagrioides males than UM traps baited with the same blend, indicating the efficiency of the SRPV traps in monitoring field population of S. nonagrioides. The study also showed that the synthetic pheromone-baited SRPV trap caught three times less adult males than the same traps baited with virgin females indicating that the synthetic blend was less attractive than the natural blend released by virgin females. However, despite the lower number of catches in the SRPV traps baited with synthetic pheromones, there was a significant and positive relationship between the number of catches in SRPV traps baited with the synthetic pheromone and with the females. This result indicates that synthetic pheromones can be used as baits in SRPV traps to monitor S. nonagrioides adult population in commercial maize crops. Nevertheless, to use the synthetic pheromone to monitor S. nonagrioides population effectively in the field, further refinement and improvement of the synthetic blend should be carried out in order to obtain a blend that is equally as attractive as the natural blend released by virgin females. [source]

Calling behaviour of adult female Helicoverpa armigera (Hübner) (Lep., Noctuidae) of overwintering generation and effects of mating

JOURNAL OF APPLIED ENTOMOLOGY, Issue 2 2000
M. L. Hou
The calling behaviour of overwintering generation females of Helicoverpa armigera and the effects of mating were studied in the laboratory at 24 ± 1°C and under reversed light-dark cycle (16 h light : 8 h dark). Age had a significant influence on calling patterns. Based on calling age, mean number of calling bouts and total calling length of virgin females increased significantly, and mean onset time of calling advanced significantly from calling day 1 to subsequent calling days. Females of the overwintering generation exhibited more short bouts in calling, and some females that initiated calling on a previous day did not call on subsequent days. Mating had no effect on the overall patterns, but did affect calling behaviour. Mated females did not resume calling after mating during the same scotophase and, on the day following mating, mated females called less frequently and for a shorter duration, but thereafter increased to the same level of virgin females of the same calling age. Furthermore, as the moth aged, the percentage of mated females calling was lower than that of virgin females. [source]

Diet and social conditions during sexual maturation have unpredictable influences on female life history trade-offs

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2009
E. L. B. BARRETT
Abstract The trade-off between gametes and soma is central to life history evolution. Oosorption has been proposed as a mechanism by which females can redirect nutrients invested in oocytes into survival when conditions for reproduction are poor. Although positive correlations between oocyte degradation and lifespan have been documented in oviparous insects, the adaptive significance of this process in species with more complex reproductive biology has not been explored. Further, environmental condition is a multivariate state, and combinations of environmental stresses may interact in unpredictable ways. Previous work on the ovoviviparous cockroach, Nauphoeta cinerea, revealed that females manipulated to mate late relative to sexual maturation experience age-related loss in fecundity because of loss of viable oocytes via apoptosis. This loss in fecundity is correlated with a reduction in female mate choice. Food deprivation while mating is delayed further increases levels of oocyte apoptosis, but the relationship between starvation-induced apoptosis and life history are unknown. To investigate this, virgin females were either fed or starved from eclosion until provided with a mate at a time known to be suboptimal for fertility. Following mating, females were fed for the duration of their lifespan. We measured lifetime reproductive performance. Contrary to predictions, under conditions of delayed mating opportunity, starved females had greater fecundity, gave birth to more high-quality offspring and had increased longevity compared with that of fed females. We suggest that understanding proximal mechanisms underlying life history trade-offs, including the function of oocyte apoptosis, and how these mechanisms respond to varied environmental conditions is critical. [source]

The paternal-sex-ratio (PSR) chromosome in natural populations of Nasonia (Hymenoptera: Chalcidoidea)

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 6 2000
L. W. Beukeboom
Selfish genetic elements may be important in promoting evolutionary change. Paternal sex ratio (PSR) is a selfish B chromosome that causes all-male families in the haplodiploid parasitic wasp Nasonia vitripennis, by inducing paternal genome loss in fertilized eggs. The natural distribution and frequency of this chromosome in North American populations of N. vitripennis was investigated using a combination of phenotypic and molecular assays. Sampling throughout North America failed to recover PSR except from populations in the Great Basin area of western North America. Extensive sampling of Great Basin populations revealed PSR in frequencies ranging from 0 to 6% at different collection sites, and extended its distribution to Idaho and Wyoming. Intensive sampling in upstate New York did not detect the chromosome. Frequencies of the maternal-sex ratio distorter (MSR), son killer (SK) and virgin females ranged from 0 to 12%. Paternal sex ratio may be restricted to the Great Basin because its spread is hampered by geographical barriers, or because populations in other areas are not conducive to PSR maintenance. However, it cannot be ruled out that PSR occurs in other regions at very low frequencies. The apparent limited distribution and low frequency of PSR suggest that it will have relatively little impact on genome evolution in Nasonia. [source]

Expression of GABAB Receptors in Magnocellular Neurosecretory Cells of Male, Virgin Female and Lactating Rats

Sperm transfer during mating in the pharaoh's ant, Monomorium pharaonis

PHYSIOLOGICAL ENTOMOLOGY, Issue 3 2006
D. ALLARD
Abstract Sperm transfer in the pharaoh's ant Monomorium pharaonis (L.) is studied by making longitudinal sections through the gasters of mating pairs fixed in copula. Sperm is transferred inside a spermatophore similar to those found in two other ants, Diacamma sp. from Japan and Carebara vidua. Sharp teeth-ridges are present on the penis valves and, during copulation, these teeth make contact with a thick and soft cuticular layer covering the bursa copulatrix. This ensures an attachment long enough for the successful transfer of the spermatophore to the right position inside the female oviduct. The thick cuticle also protects the queen from serious damage by the male's sharp claspers. After a first successful copulation, sperm is still present inside the male's seminal vesicles, suggesting that males can mate multiply. Additional experiments, where single, initially virgin males are presented to several virgin females, confirm this. [source]

Fragrances, male display and mating behaviour of Euglossa hemichlora: a flight cage experiment

PHYSIOLOGICAL ENTOMOLOGY, Issue 4 2003
Thomas Eltz
Abstract., Male euglossine bees (Apidae: Euglossini) collect volatile substances (fragrances) from floral and nonfloral sources and store them in hair-filled cavities in their hind tibiae. Over time, males accumulate large quantities of complex and species-specific blends of fragrances. Various hypotheses have been put forward to explain this behaviour, including the idea that fragrance stores reflect the genetic quality of individual males and have evolved through sexual selection and female choice. Clear support of this hypothesis is lacking, largely because male,female interactions are both rare and difficult to observe in nature. Here, we report a flight cage experiment performed in Panama that permitted mating between virgin females (raised from brood cells) and males captured in the forest at fragrance baits. In the cage, eight individually marked males defended small territories around vertical perch sites and showed a characteristic display, which included a previously unreported ,leg-crossing' movement, possibly related to fragrance release. A total of six copulations and three copulatory attempts by Euglossa hemichlora were observed and partly recorded on video. The copulations, all of which were initiated by the female landing on a male perch, were short (4,10 s) and showed no signs of the transfer of chemical substances from male to female. In some cases, the male hovered directly over the female before descending to mount her, possibly facilitating fragrance evaluation by the female. After the experiment, the contents of the males' hind legs were analysed by gas chromatography-mass spectroscopy, which detected complex mixtures of terpenoids and aromatics (totalling 70 different compounds) dominated by hexahydrofarnesyl acetone, farnesene epoxide, ocimene and p -dimethoxy benzene. Individual total amounts of fragrances were neither related to display activity or perch occupancy by given males, nor to the frequency of matings achieved. Display activity was the only positive correlate of mating frequency. Generally, individuals had uniformly large amounts of stored fragrances in comparison to a previous study of three other species of Panamanian Euglossa. [source]

The biosynthesis of Juvenile Hormone, its degradation and titres in females of the true armyworm: a comparison of migratory and non-migratory populations

PHYSIOLOGICAL ENTOMOLOGY, Issue 2 2000
Jeremy N. McNeil
Summary In a previous study [McNeil et al. (1996) Archives of Insect Biochemistry and Physiology, 32, 575,584], patterns of sexual maturation and Juvenile Hormone (JH) biosynthesis were compared in virgin females from migratory (North American) and non-migratory (Azorean) populations of the true armyworm moth, Pseudaletia unipuncta Haworth (Lepidoptera: Noctuidae). Sexual maturation occurred at a significantly earlier age after emergence in the non-migrant population, and the rates of biosynthesis of JH in vitro suggested that lower titres of JH may be required to initiate the onset of calling behaviour (pheromone emission) and ovarian development in Azorean females. To examine the physiological differences in the reproductive biology of migratory and non-migratory populations in greater detail, the haemolymph titres of JH and JH esterase activity were compared in virgin females as a function of age. In addition, the effects of mating on JH biosynthesis in vitro, JH titres, JH esterase activity and egg production were measured in the two populations. As expected, JH titres rose more rapidly after emergence in Azorean females than in their North American counterparts but, contrary to our prediction, the maximum levels were also higher in the non-migrant population. Activity of JH esterase was much higher in Azorean females on the day of emergence. However, by the second day both populations had similar activity levels (about 17 nmol JH/min/ml) and exhibited a similar age-related decline in subsequent days. Mating did not affect the rate of JH biosynthesis in vitro but resulted in a significant increase in the titres of JH in the haemolymph of both populations. The maximum titre (a five-fold increase) occurred within 24 h of mating in Azorean females. In North American individuals the increase was greater (seven-fold) but did not occur until 48 h after mating. No difference in the activity of JH esterase was observed between mated and virgin North American females. By contrast, while there was an age-related decline in the activity of JH esterase in mated Azorean females, as seen in both North American groups, activity levels in virgin females remained constant with age. In all females, mating resulted in a significant increase in egg production within 24 h. The Azores is a volcanic archipelago, so these non-migratory populations were probably founded by immigrants originating from migratory continental populations. It is clear from our results that the change from a life history that includes migration to a non-migratory one involved more than just a temporal shift in the timing of the production of JH. Furthermore, the interpopulation differences in titres of JH and mating-induced changes reported here cannot be fully explained by the observed differences in the patterns of activity of JH esterase and JH biosynthesis in vitro. [source]

Copula duration and sperm storage in Mediterranean fruit flies from a wild population

PHYSIOLOGICAL ENTOMOLOGY, Issue 1 2000
P.H.illip W. Taylor
Summary In the Mediterranean fruit fly (Ceratitis capitata Weidemann, ,medfly'), a lekking tephritid, evidence from laboratory studies of flies from laboratory strains suggests that copulation is shorter, and sperm storage more abundant, if males are large or protein-fed, and that copulation is longer when females are large. In addition, sperm tend to be stored asymmetrically between the female's two spermathecae and this asymmetry declines with abundance of stored sperm. The primary objective of this study was to investigate whether these trends persist in other experimental contexts that bear closer resemblance to nature. Accordingly, we carried out experiments in a field-cage using males derived as adults from a wild population and virgin females reared from naturally infested fruit. The results of this study were consistent with laboratory studies in that copula duration increased with female size, that sperm were stored asymmetrically between the females' spermathecae, and that this asymmetry declined with number of sperm stored. However, we also found some previously unreported effects of female size; large females stored more sperm and stored sperm more asymmetrically between their two spermathecae than did small females. Unlike the laboratory studies, copula duration and sperm storage patterns were unaffected by male size and diet. This may be due to overwhelming variation from other sources in the wild-collected males used, as well as environmental variability in the semi-natural setting. [source]

Juvenile hormone III produced in male accessory glands of the longhorned beetle, Apriona germari, is transferred to female ovaries during copulation

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 1 2010
Ling Tian
Abstract We report on juvenile hormone (JH) biosynthesis in vitro by male accessory glands (MAGs) in the longhorned beetle, Aprionona germari, accompanied by the transfer of JH from males to females during copulation. JH was extracted from the MAGs and separated by reversed-phase high-performance liquid chromatography. JH III was identified as the major JH by gas chromatography,mass spectrometry. A radiochemical assay and a non-radioactive method were used to measure the in vitro rate of JH biosynthesis by the MAGs. After 4,h of incubation with 3H-methionine in the medium, the radioactivity in the MAGs substantially increased. In a separate assay, incubation of the MAGs with non-radioactive methionine for 4,h resulted in a 39% increase in JH III. Seven-day-old males were injected with medium 199 containing 3H,methionine and 24,h later they were mated with virgin females. Hemolymph and the MAGs were collected from the mated males and hemolymph, ovaries and eggs were collected from the mated females for assaying radioactive JH. The radioactivity incorporated into JH in the MAGs was transferred to the females during copulation and later transferred into their eggs. Assayed 1,h after copulation, JH III level in the MAGs decreased 42% and the content of JH III in the male hemolymph did not change, whereas the content of JH III in the female hemolymph and ovaries both increased. © 2010 Wiley Periodicals, Inc. [source]

Female sex pheromone suppression and the fate of sex-peptide-like peptides in mated moths of Helicoverpa armigera

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2007
V.K. Nagalakshmi
Abstract Insect males produce accessory gland (MAG) factors that are transferred in the seminal fluid to females during copulation, and elicit changes in the mated female's behavior and physiology. Our previous studies showed that the injection of synthetic Drosophila melanogaster sex-peptide (DrmSP) into virgin females of the moth Helicoverpa armigera causes a significant inhibition of pheromone production. In this and other moth species, pheromone production, correlated with female receptivity, is under neuroendocrine control due to the circadian release of the neuropeptide PBAN. In this study, we show that PBAN, present in the hemolymph during the scotophase in females, is drastically reduced after mating. We also identify 4 DrmSP-like HPLC peaks (Peaks A, S1, S2, and B) in MAGs, with increasing levels of DrmSP immunoreactivity during the scotophase, when compared to their levels observed during the photophase. In H. armigera MAGs, a significant reduction in the pheromonostatic peak (Peak B) was already evident after 15 min of copulation, and depletion of an additional peak (Peak S2) was evident after complete mating. Peak A is also detected in female brains, increasing significantly 1 h after mating, at which time inhibition of pheromone biosynthesis also occurs. However, changes corresponding to the other MAG peaks were not detected in mated female tissues. Arch. Insect Biochem. Physiol. 64:142,155, 2007. © 2007 Wiley-Liss, Inc. [source]

The piercing-sucking herbivores Lygus hesperus and Nezara viridula induce volatile emissions in plants ,,

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 2 2005
Livy Williams III
Abstract Plant volatiles induced by herbivory are often used as olfactory cues by foraging herbivores and their natural enemies, and thus have potential for control of agricultural pests. Compared to chewing insects and mites, little is known about plant volatile production following herbivory by insects with piercing-sucking mouthparts. Here, we studied factors (insect life stage, gender, the role of salivary glands, and type of bioassay used for volatile induction) that influence the induction of plant volatiles by two agriculturally important hemipterans, Lygus hesperus and Nezara viridula. Feeding on intact cotton by virgin females of L. hesperus induced 2.6-fold greater volatile response compared to that induced by mated females, possibly due to increased feeding activity by virgin females. This plant volatile response was associated with elicitors present in the insect's salivary glands as well as to the degree of mechanical injury. Feeding injury by N. viridula females also increased volatile emissions in intact maize by approximately 2-fold compared to control plants. Maize seedlings injured by N. viridula emitted higher amounts of the monoterpene linalool, the sesquiterpenes (E)-,-caryophyllene, ,- trans -bergamotene, and (E,E)-,-farnesene, and the homoterpene (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene, but not amounts of green leaf volatiles, compared to uninjured plants. Emissions from intact maize injured by adult males were lower than those emitted by adult females of the same age and did not differ from those emitted by uninjured plants. Similarly, feeding by virgin female N. viridula followed by excision led to 64% higher quantities of volatiles compared to untreated plants. Volatile emission in excised plants, however, was considerably greater than in intact plants, suggesting that careful consideration must be given to bioassay design in studies of herbivore-induced plant volatiles. Salivary gland extracts of N. viridula led to sesquiterpene emissions approximately 2.5-fold higher than for controls, although no significant differences were observed for green leaf volatiles, monoterpenes, and homoterpenes. These results indicate that L. hesperus and female N. viridula feeding induce volatile production in plants, and that volatile production is affected by gender and life stage of the bug. Although oviposition and mechanical injury by stylets may increase release of volatiles, elicitors from salivary glands of L. hesperus and N. viridula also seem to play a role in the emission of plant volatiles. Arch. Insect Biochem. Physiol. 58:84,96, 2005. Published 2005 Wiley-Liss, Inc. [source]