Improving mating performance of mass-reared sterile Mediterranean fruit flies (Diptera: Tephritidae) through changes in adult holding conditions: demography and mating competitiveness

International Nuclear Information System (INIS)

Liedo, P.; Salgado, S.; Oropeza, A.; Toledo, J.

2007-01-01

Mass rearing conditions affect the mating behavior of Mediterranean fruit flies (medflies) Ceratitis capitata (Wiedemann). We evaluated the effect of slight changes in the adult holding conditions of adult flies maintained for egg production on their mating performance. Colonization was initiated from wild flies collected as larvae from infested coffee berries (Coffea arabica L.). When pupae were close to adult emergence, they were randomly divided into 3 groups and the emerging adults were reared under the following conditions: (1) Metapa System (MS, control), consisting of 70 x 45 x 15 cm aluminum frame, mesh covered cages, with a density of 2,200 flies per cage and a 1:1 initial sex ratio; (2) Insert System (IS), with the same type of cage, and the same fly density and sex ratio as in the MS treatment, but containing twelve Plexiglas pieces (23 x 8.5 cm) to provide additional horizontal surface areas inside the cage; and (3) Sex-ratio System (SS), same as IS, but in this case the initial male: female ratio was 4:1. Three d later, newly emerged females were introduced, so the ratio became 3:1 and on the 6th d another group of newly emerged females was added to provide a 2:1 final sex ratio, at which the final density reached 1,675 flies per cage. The eggs collected from each of the 3 treatments were reared independently following standard procedures and the adults were held under the same experimental conditions. This process was repeated for over 10 to 13 generations (1 year). The experiment was repeated 3 times in 3 consecutive years, starting each replicate with a new collection of wild flies. Life tables were constructed for each treatment at the parental, 3rd, 6th, and 9th generations. Standard quality control parameters (pupation at 24 h, pupal weight, adult emergence, and flight ability), were estimated for each treatment every third generation in the third year. For the last generation each year, mating competitiveness was evaluated in field cage tests

Mate preference of female blue tits varies with experimental photoperiod.

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Laura B Reparaz

Full Text Available Organisms use environmental cues to time their life-cycles and among these cues, photoperiod is the main trigger of reproductive behaviours such as territory defence or song activity. Whether photoperiod is also important for another behaviour closely associated with reproduction, mate choice, is unknown. In many bird species, mate choice occurs at two different times during the annual cycle that strongly differ in daylength: in late winter when photoperiod is short and social mates are chosen, and again around egg-laying when photoperiod is longer and extra-pair mates are chosen. This duality makes the role that photoperiod plays on mate choice behaviours intriguing. We investigated the effect of photoperiod on mate choice using three experimental photoperiodic treatments (9 L:15 D, 14 L:10 D, 18 L:6 D, using blue tits (Cyanistes caeruleus as a biological model. We show that female choice was stronger under long photoperiods. In addition, female blue tits spent significantly more time near males with long tarsi and long wings. This latter preference was only expressed under long photoperiods, suggesting that some indices of male quality only become significant to females when they are strongly photostimulated, and therefore that females could select their social and extra-pair mates based on different phenotypic traits. These results shed light on the roles that photoperiod may play in stimulating pair-bonding and in refining female selectivity for male traits.

Hybrid female mate choice as a species isolating mechanism: environment matters.

Science.gov (United States)

Schmidt, E M; Pfennig, K S

2016-04-01

A fundamental goal of biology is to understand how new species arise and are maintained. Female mate choice is potentially critical to the speciation process: mate choice can prevent hybridization and thereby generate reproductive isolation between potentially interbreeding groups. Yet, in systems where hybridization occurs, mate choice by hybrid females might also play a key role in reproductive isolation by affecting hybrid fitness and contributing to patterns of gene flow between species. We evaluated whether hybrid mate choice behaviour could serve as such an isolating mechanism using spadefoot toad hybrids of Spea multiplicata and Spea bombifrons. We assessed the mate preferences of female hybrid spadefoot toads for sterile hybrid males vs. pure-species males in two alternative habitat types in which spadefoots breed: deep or shallow water. We found that, in deep water, hybrid females preferred the calls of sterile hybrid males to those of S. multiplicata males. Thus, maladaptive hybrid mate preferences could serve as an isolating mechanism. However, in shallow water, the preference for hybrid male calls was not expressed. Moreover, hybrid females did not prefer hybrid calls to those of S. bombifrons in either environment. Because hybrid female mate choice was context-dependent, its efficacy as a reproductive isolating mechanism will depend on both the environment in which females choose their mates as well as the relative frequencies of males in a given population. Thus, reproductive isolation between species, as well as habitat specific patterns of gene flow between species, might depend critically on the nature of hybrid mate preferences and the way in which they vary across environments. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Variability of female responses to conspecific vs. heterospecific male mating calls in polygynous deer: an open door to hybridization?

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Megan T Wyman

Full Text Available Males of all polygynous deer species (Cervinae give conspicuous calls during the reproductive season. The extreme interspecific diversity that characterizes these vocalizations suggests that they play a strong role in species discrimination. However, interbreeding between several species of Cervinae indicates permeable interspecific reproductive barriers. This study examines the contribution of vocal behavior to female species discrimination and mating preferences in two closely related polygynous deer species known to hybridize in the wild after introductions. Specifically, we investigate the reaction of estrous female red deer (Cervus elaphus to playbacks of red deer vs. sika deer (Cervus nippon male mating calls, with the prediction that females will prefer conspecific calls. While on average female red deer preferred male red deer roars, two out of twenty females spent more time in close proximity to the speaker broadcasting male sika deer moans. We suggest that this absence of strict vocal preference for species-specific mating calls may contribute to the permeability of pre-zygotic reproductive barriers observed between these species. Our results also highlight the importance of examining inter-individual variation when studying the role of female preferences in species discrimination and intraspecific mate selection.

Mating changes the female dietary preference in the two-spotted cricket, Gryllus bimaculatus

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Yusuke eTsukamoto

2014-03-01

Full Text Available Most insect species exhibit characteristic behavioral changes after mating. Typical post-mating behaviors in female insects include noticeable increases in food intake, elevated oviposition rates, lowered receptivity to courting males, and enhanced immune response. Although it has been reported that mated females of several insect species including the fruit fly, Drosophila melanogaster increase the amount of food intake and change their dietary preferences, the limited number of comparative studies prevent the formulation of generalities regarding post-mating behaviors in other insects in particular amongst orthopteran species. Here, we investigated whether females of the two-spotted cricket, Gryllus bimaculatus, alter their feeding behavior after mating. Although significant differences in the amount of food intake after mating were not observed, all experimental data indicated a clear trend among crickets towards the ingestion of larger quantities of food. Geometric framework analyses revealed that the mated female crickets preferred food with higher protein content compared to virgin female crickets. This implies that this species required different nutritional demands after mating. These findings further expand our understanding of the behavioral and biological changes that are triggered in female insects post-mating, and highlight the potential for this species in investigating the molecular-based nutritional dependent activities that are linked to post-mating behaviors.

Vocal neighbour-mate discrimination in female great tits despite high song similarity

DEFF Research Database (Denmark)

Blumenrath, Sandra H.; Dabelsteen, Torben; Pedersen, Simon Boel

2007-01-01

Discrimination between conspecifics is important in mediating social interactions between several individuals in a network environment. In great tits, Parus major, females readily distinguish between the songs of their mate and those of a stranger. The high degree of song sharing among neighbouring...... males, however, raises the question of whether females are also able to perceive differences between songs shared by their mate and a neighbour. The great tit is a socially monogamous, hole-nesting species with biparental care. Pair bond maintenance and coordination of the pair's reproductive efforts...... are important, and the female's ability to recognize her mate's song should therefore be adaptive. In a neighbour-mate discrimination playback experiment, we presented 13 incubating great tit females situated inside nestboxes with a song of their mate and the same song type from a neighbour. Each female...

Genetic Coupling of Female Mate Choice with Polygenic Ecological Divergence Facilitates Stickleback Speciation.

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Bay, Rachael A; Arnegard, Matthew E; Conte, Gina L; Best, Jacob; Bedford, Nicole L; McCann, Shaugnessy R; Dubin, Matthew E; Chan, Yingguang Frank; Jones, Felicity C; Kingsley, David M; Schluter, Dolph; Peichel, Catherine L

2017-11-06

Ecological speciation with gene flow is widespread in nature [1], but it presents a conundrum: how are associations between traits under divergent natural selection and traits that contribute to assortative mating maintained? Theoretical models suggest that genetic mechanisms inhibiting free recombination between loci underlying these two types of traits (hereafter, "genetic coupling") can facilitate speciation [2-4]. Here, we perform a direct test for genetic coupling by mapping both divergent traits and female mate choice in a classic model of ecological speciation: sympatric benthic and limnetic threespine stickleback (Gasterosteus aculeatus). By measuring mate choice in F2 hybrid females, we allowed for recombination between loci underlying assortative mating and those under divergent ecological selection. In semi-natural mating arenas in which females had access to both benthic and limnetic males, we found that F2 females mated with males similar to themselves in body size and shape. In addition, we found two quantitative trait loci (QTLs) associated with female mate choice that also predicted female morphology along the benthic-limnetic trait axis. Furthermore, a polygenic genetic model that explains adaptation to contrasting benthic and limnetic feeding niches [5] also predicted F2 female mate choice. Together, these results provide empirical evidence that genetic coupling of assortative mating with traits under divergent ecological selection helps maintain species in the face of gene flow, despite a polygenic basis for adaptation to divergent environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Self-referent phenotype matching and its role in female mate choice in arthropods

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Carie B. WEDDLE, John HUNT, Scott K. SAKALUK

2013-04-01

Full Text Available A growing body of empirical evidence shows that females of many animal species gain benefits by mating polyandrously, and often prefer to mate with novel males over previous mates. Although a female preference for novel males has been demonstrated for multiple animal taxa, the mechanisms used by females to discriminate between novel and previous mates remain largely unknown. However, recent studies suggest that in decorated crickets Gryllodes sigillatus, females actually imbue males with their own chemical cues, known as cuticular hydrocarbons (CHCs during mating, and utilize chemosensory self-referencing to recognize recent mates. Here we review evidence that self-referent phenotype matching is a widespread mechanism of recognition in arthropods, and explore how CHCs are used to facilitate mate-choice decisions. There is substantial evidence that CHCs are used as recognition cues to discriminate between species, kin, sexes, mates, individuals, and self and non-self, and are used to facilitate mate-choice decisions in a wide range of arthropod taxa. There is also evidence that CHCs are often transferred between individuals during direct physical contact, including copulation. Chemosensory self-referencing via cuticular hydrocarbons could provide a simple, but reliable mechanism for identifying individuals from previous mating encounters. This mechanism does not require any specialized cognitive abilities because an individual’s phenotype is always available for reference. Given the ubiquitous use of CHCs among arthropods, chemosensory self-referencing may be a widespread mechanism used by female arthropods to facilitate female mate-choice decisions and to enhance opportunities for polyandry [Current Zoology 59 (2: 239-248, 2013].

Sexual Dimorphism and Mating Behavior in Anomala testaceipennis

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Rodrigues, Sérgio Roberto; Gomes, Elias Soares; Bento, José Maurício Simões

2014-01-01

Abstract The beetle, Anomala testaceipennis Blanchard (Coleoptera: Scarabaeidae), occurs in central-western Brazil where larvae feed on the roots of plants causing damage. This research aimed to study sexual dimorphism and mating behavior of A. testaceipennis . Adults of A. testaceipennis were collected with light traps in the experimental area of the State University of Mato Grosso do Sul, in Aquidauana. Laboratory experiments were performed to describe copulation behavior and adult morphology of males and females. In males the last abdominal segment has a pronounced constriction, which is absent in females, and the male’s last segment of the first pair of legs has a ventral projection, which is poorly developed in females. The mating activities of adults begin soon after sunset, when adults leave the soil and fly. When the male encounters a female, he touches her with antennae and tarsi. If accepted, the male climbs on the female and remains on her back, and soon after the copulation begins. When the female does not accept the male for mating, she moves rapidly and can roll on the ground, and by so removing the male. In the field, adults feed and mate on bloomed trees of Oiti, Licania tomentosa Benth (Malpighiales: Chrysobalanaceae) and Louro, Cordia glabrata Martius (Boraginaceae). In trees without inflorescences no adults of this species were found. PMID:25502043

The smell of virgins: mating status of females affects male swimming behaviour in Oithona davisae

DEFF Research Database (Denmark)

Heuschele, Jan; Kiørboe, Thomas

2012-01-01

in the presence of virgin when compared with mated females and that the cue is waterborne. The ability to distinguish between virgin and mated females may reduce male mortality during mate search and the cost related to mating behaviour (precopula) in both sexes. We estimate that at realistic population densities...... the ability of males to distinguish between virgin and mated females saves them several hours per day of dangerous and energetically expensive fast female tracking...

Mating Success of Female Dungeness Crabs (Cancer magister) in Oregon Coastal Waters

DEFF Research Database (Denmark)

Dunn, Paul; Shanks, Alan

2012-01-01

year, and when combined with crabs that carried sperm from previous mating encounters (females store sperm), the percent of females that would have produced viable eggs was 83%. Crabs that definitely molted during the collection year showed higher mating success (95%). The largest females examined...

Dynamic, mating-induced gene expression changes in female head and brain tissues of Drosophila melanogaster

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Stirling Emma J

2010-10-01

Full Text Available Abstract Background Drosophila melanogaster females show changes in behavior and physiology after mating that are thought to maximize the number of progeny resulting from the most recent copulation. Sperm and seminal fluid proteins induce post-mating changes in females, however, very little is known about the resulting gene expression changes in female head and central nervous system tissues that contribute to the post-mating response. Results We determined the temporal gene expression changes in female head tissues 0-2, 24, 48 and 72 hours after mating. Females from each time point had a unique post-mating gene expression response, with 72 hours post-mating having the largest number of genes with significant changes in expression. At most time points, genes expressed in the head fat body that encode products involved in metabolism showed a marked change in expression. Additional analysis of gene expression changes in dissected brain tissues 24 hours post-mating revealed changes in transcript abundance of many genes, notably, the reduced transcript abundance of genes that encode ion channels. Conclusions Substantial changes occur in the regulation of many genes in female head tissues after mating, which might underlie aspects of the female post-mating response. These results provide new insights into the physiological and metabolic changes that accompany changes in female behaviors.

Sharing mates and nest boxes is associated with female "friendship" in European starlings, Sturnus vulgaris.

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Henry, Laurence; Bourguet, Cécile; Coulon, Marion; Aubry, Christine; Hausberger, Martine

2013-02-01

Breeding decisions in birds involve both mate and nest choice, and there is increasing evidence that social influences may modulate individual choices. Female preferences may be affected by other females' preferences and mutual choice cannot always be excluded, which makes the whole pattern more complex than assumed by most sexual selection models. Social transmission may be facilitated by particular social bonds, therefore prebreeding social networks may influence later mate choices. The other case where females share mate or resources is polygyny, generally viewed to only benefit males. If mutual benefits may arise then mechanisms should evolve to reduce the reproductive cost for females such as to reduce the cost of aggression by sharing their mate with a preferred same-sex social partner. We tested the hypothesis that females' mating decisions may be influenced by the prebreeding social network and that social partner relations established prior to breeding may share decisions (mate/sites) in a facultatively polygynous species, the European starling. Two experiments were designed to test the relative importance of male or nest by following the whole dynamics of the breeding cycle from the prebreeding period until mate and nest selection. In both cases socially isolated females tended to be excluded from breeding, while prebreeding social partners tended to share mates and to nest in close proximity, mate copying leading in some case to polygyny. The final pattern resulted both from female "likes and dislikes" and male preferences for some females. Aggressive interactions between females were rare. Vocal sharing between females may have been a clue for males as to the degree of social integration of these females. PsycINFO Database Record (c) 2013 APA, all rights reserved

Choosy but not chaste: multiple mating in human females.

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Scelza, Brooke A

2013-01-01

When Charles Darwin set out to relate his theory of evolution by natural selection to humans he discovered that a complementary explanation was needed to properly understand the great variation seen in human behavior. The resulting work, The Descent of Man and Selection in Relation to Sex, laid out the defining principles and evidence of sexual selection. In brief, this work is best known for illuminating the typically male strategy of intrasexual competition and the typically female response of intersexual choice. While these sexual stereotypes were first laid out by Darwin, they grew in importance when, years later, A. J. Bateman, in a careful study of Drosophila mating strategies, noted that multiple mating appeared to provide great benefit to male reproductive success, but to have no such effect on females. As a result, female choice soon became synonymous with being coy, and only males were thought to gain from promiscuous behavior. However, the last thirty years of research have served to question much of the traditional wisdom about sex differences proposed by Darwin and Bateman, illuminating the many ways that women (and females more generally) can and do engage in multiple mating. Copyright © 2013 Wiley Periodicals, Inc.

Last mated male sperm precedence in doubly mated females is not ...

Indian Academy of Sciences (India)

DST Unit on Evolution and Genetics, Department of Studies in Zoology, University of Mysore, Manasagangotri,. Mysore 570 006, India .... using SPSS software (ver. 16.0). Results ... Proportions of first male and second male progeny of doubly mated female and the results of paired-sample t-test carried out independently for ...

Serotonin-induced mate rejection in the female cabbage butterfly, Pieris rapae crucivora

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Obara, Yoshiaki; Fukano, Yuya; Watanabe, Kenta; Ozawa, Gaku; Sasaki, Ken

2011-11-01

Virgin female cabbage butterflies, Pieris rapae crucivora, accept and mate with courting males, whereas mated females reject them and assume the "mate refusal posture". This study tested whether the biogenic amines, serotonin (5HT), dopamine (DA), and octopamine (OA), were responsible for this change in behavior. The results showed that 2-3-day-old virgin females fed with 5HT rejected courting males significantly more frequently compared with controls fed on sucrose. In contrast, the proportions of courting males rejected by virgin females fed with either DA or OA did not differ from sucrose-fed controls. Oral application of each amine resulted in significantly increased levels of the amine applied (or its metabolite) in the brain. The results strongly suggest that 5HT or a 5HT metabolite may be responsible for the post-mating change in behavioral response of 2-3-day-old virgin females to courting males. Similar effects of 5HT treatment were observed in 6-8-day-old virgin females, but in this case the results were only marginally different from the controls, suggesting that the effect may decline with increasing female age.

Females Choose Mates Based on Genetic Relatedness in a Small Dasyurid Marsupial, the Agile Antechinus (Antechinus agilis.

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Marissa L Parrott

Full Text Available Females in a variety of taxa mate with more than one male during a single oestrus and exhibit mate preferences for genetically compatible males, but the influence of female mate choice on siring success is not clearly understood. Whether females choose to mate with more than one male or endure forced copulations is also often unknown. Here, we examined the effects of genetic relatedness on female mate choice and siring success in a small semelparous carnivorous marsupial, the agile antechinus (Antechinus agilis, during two consecutive breeding seasons. Experimental trials were conducted in captivity over periods of 72 hours using interconnected enclosures in which female antechinus could choose to access any of four separated males, but males were only able to access females that entered their quarters. Females had access to two genetically similar and two genetically dissimilar males simultaneously and all behavioural interactions were observed and scored from continuous video recordings. Genetic similarity between mates and paternity of young was determined by microsatellite analyses. Some females chose to enter and mate with more than one male during a single oestrus period. Although females investigated all males, they spent significantly more time visiting, and mated more times with, genetically dissimilar males. Males that were genetically dissimilar to the female sired 88% of subsequent offspring. Whilst males mated readily with most females, they rejected the advances of some receptive females, indicating a previously unexpected level of male mate choice. The results show that genetic relatedness between mates has a significant influence on mate choice, breeding and siring success in the agile antechinus.

Does foraging behaviour affect female mate preferences and pair formation in captive zebra finches?

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Neeltje J Boogert

Full Text Available BACKGROUND: Successful foraging is essential for survival and reproductive success. In many bird species, foraging is a learned behaviour. To cope with environmental change and survive periods in which regular foods are scarce, the ability to solve novel foraging problems by learning new foraging techniques can be crucial. Although females have been shown to prefer more efficient foragers, the effect of males' foraging techniques on female mate choice has never been studied. We tested whether females would prefer males showing the same learned foraging technique as they had been exposed to as juveniles, or whether females would prefer males that showed a complementary foraging technique. METHODOLOGY/PRINCIPAL FINDINGS: We first trained juvenile male and female zebra finches (Taeniopygia guttata to obtain a significant proportion of their food by one of two foraging techniques. We then tested whether females showed a preference for males with the same or the alternative technique. We found that neither a male's foraging technique nor his foraging performance affected the time females spent in his proximity in the mate-choice apparatus. We then released flocks of these finches into an aviary to investigate whether assortative pairing would be facilitated by birds taught the same technique exploiting the same habitat. Zebra finches trained as juveniles in a specific foraging technique maintained their foraging specialisation in the aviary as adults. However, pair formation and nest location were random with regard to foraging technique. CONCLUSIONS/SIGNIFICANCE: Our findings show that zebra finches can be successfully trained to be foraging specialists. However, the robust negative results of the conditions tested here suggest that learned foraging specializations do not affect mate choice or pair formation in our experimental context.

Neurogenesis in the olfactory bulb induced by paced mating in the female rat is opioid dependent.

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Marianela Santoyo-Zedillo

Full Text Available The possibility to control the rate of sexual stimulation that the female rat receives during a mating encounter (pacing increases the number of newborn neurons that reach the granular layer of the accessory olfactory bulb (AOB. If females mate repeatedly, the increase in the number of neurons is observed in other regions of the AOB and in the main olfactory bulb (MOB. It has also been shown that paced mating induces a reward state mediated by opioids. There is also evidence that opioids modulate neurogenesis. In the present study, we evaluated whether the opioid receptor antagonist naloxone (NX could reduce the increase in neurogenesis in the AOB induced by paced mating. Ovariectomized female rats were randomly divided in 5 different groups: 1 Control (not mated treated with saline, 2 control (not mated treated with naloxone, 3 females that mated without controlling the sexual interaction (no-pacing, 4 females injected with saline before pacing the sexual interaction and 5 females injected with NX before a paced mating session. We found, as previously described, that paced mating induced a higher number of new cells in the granular layer of the AOB. The administration of NX before paced mating, blocked the increase in the number of newborn cells and prevented these cells from differentiating into neurons. These data suggest that opioid peptides play a fundamental role in the neurogenesis induced by paced mating in female rats.

An experimental test of condition-dependent male and female mate choice in zebra finches.

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Marie-Jeanne Holveck

Full Text Available In mating systems with social monogamy and obligatory bi-parental care, such as found in many songbird species, male and female fitness depends on the combined parental investment. Hence, both sexes should gain from choosing mates in high rather than low condition. However, theory also predicts that an individual's phenotypic quality can constrain choice, if low condition individuals cannot afford prolonged search efforts and/or face higher risk of rejection. In systems with mutual mate choice, the interaction between male and female condition should thus be a better predictor of choice than either factor in isolation. To address this prediction experimentally, we manipulated male and female condition and subsequently tested male and female mating preferences in zebra finches Taeniopygia guttata, a songbird species with mutual mate choice and obligatory bi-parental care. We experimentally altered phenotypic quality by manipulating the brood size in which the birds were reared. Patterns of association for high- or low-condition individuals of the opposite sex differed for male and female focal birds when tested in an 8-way choice arena. Females showed repeatable condition-assortative preferences for males matching their own rearing background. Male preferences were also repeatable, but not predicted by their own or females' rearing background. In combination with a brief review of the literature on condition-dependent mate choice in the zebra finch we discuss whether the observed sex differences and between-studies differences arise because males and females differ in context sensitivity (e.g. male-male competition suppressing male mating preferences, sampling strategies or susceptibility to rearing conditions (e.g. sex-specific effect on physiology. While a picture emerges that juvenile and current state indeed affect preferences, the development and context-dependency of mutual state-dependent mate choice warrants further study.

Worthless and Nutritive Nuptial Gifts: Mating Duration, Sperm Stored and Potential Female Decisions in Spiders.

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Maria J Albo

Full Text Available In nuptial gift-giving species females sometimes select their potential mates based on the presence and size of the gift. But in some species, such as the Neotropical polyandrous spider Paratrechalea ornate male gifts vary in quality, from nutritive to worthless, and this male strategy can be in conflict with female nutritional benefits. In this species, males without gifts experience a reduction in mating success and duration, while males that offer worthless or genuine nutritive gifts mate with similar frequencies and durations. The female apparently controls the duration of copulation. Thus, there is scope for females to favour males offering gifts and further if these are nutritious, via post-copulatory processes. We first tested whether females differentially store sperm from males that offer the highest nutritional benefits by experimentally presenting females with males that offer either nutritive or worthless gifts (uninterrupted matings. Second, we carried out another set of experiments to examine whether females can select sperm based only on gift presence. This time we interrupted matings after the first pedipalp insertion, thus matching number of insertions and mating duration for males that: offered and did not offer gift. Our results showed that the amount of sperm stored is positive related to mating duration in all groups, except in matings with worthless gifts. Gift presence itself did not affect the sperm stored by females, while they store similar number of sperm in matings with males offering either nutritive or worthless gifts. We discuss whether females prefer males with gifts regardless, if content, because it represents an attractive and/or reliable signal. Or alternatively, they prefer nutritive nuptial gifts, as they are an important source of food supply and/or signal of male donor ability.

Direct observation of female mating frequency using time-lapse photography

NARCIS (Netherlands)

Kuijper, Bram; Morrow, Edward H.

2009-01-01

One basic condition of postmating sexual selection is that females mate more than once before fertilizing their ova. Knowledge of the frequency and extent of multiple mating in a given population or species is therefore important in order to fully understand the potential for sexual selection, in

Predator-induced changes of female mating preferences: innate and experiential effects

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Indy Jeane

2011-07-01

Full Text Available Abstract Background In many species males face a higher predation risk than females because males display elaborate traits that evolved under sexual selection, which may attract not only females but also predators. Females are, therefore, predicted to avoid such conspicuous males under predation risk. The present study was designed to investigate predator-induced changes of female mating preferences in Atlantic mollies (Poecilia mexicana. Males of this species show a pronounced polymorphism in body size and coloration, and females prefer large, colorful males in the absence of predators. Results In dichotomous choice tests predator-naïve (lab-reared females altered their initial preference for larger males in the presence of the cichlid Cichlasoma salvini, a natural predator of P. mexicana, and preferred small males instead. This effect was considerably weaker when females were confronted visually with the non-piscivorous cichlid Vieja bifasciata or the introduced non-piscivorous Nile tilapia (Oreochromis niloticus. In contrast, predator experienced (wild-caught females did not respond to the same extent to the presence of a predator, most likely due to a learned ability to evaluate their predators' motivation to prey. Conclusions Our study highlights that (a predatory fish can have a profound influence on the expression of mating preferences of their prey (thus potentially affecting the strength of sexual selection, and females may alter their mate choice behavior strategically to reduce their own exposure to predators. (b Prey species can evolve visual predator recognition mechanisms and alter their mate choice only when a natural predator is present. (c Finally, experiential effects can play an important role, and prey species may learn to evaluate the motivational state of their predators.

Pheromonal Cues Deposited by Mated Females Convey Social Information about Egg-Laying Sites in Drosophila Melanogaster.

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Duménil, Claire; Woud, David; Pinto, Francesco; Alkema, Jeroen T; Jansen, Ilse; Van Der Geest, Anne M; Roessingh, Sanne; Billeter, Jean-Christophe

2016-03-01

Individuals can make choices based on information learned from others, a phenomenon called social learning. How observers differentiate between which individual they should or should not learn from is, however, poorly understood. Here, we showed that Drosophila melanogaster females can influence the choice of egg-laying site of other females through pheromonal marking. Mated females mark territories of high quality food by ejecting surplus male sperm containing the aggregation pheromone cis-11-vaccenyl acetate (cVA) and, in addition, deposit several sex- and species-specific cuticular hydrocarbon (CHC) pheromones. These pheromonal cues affect the choices of other females, which respond by preferentially laying eggs on the marked food. This system benefits both senders and responders, as communal egg laying increases offspring survival. Virgin females, however, do not elicit a change in the egg-laying decision of mated females, even when food has been supplemented with ejected sperm from mated females, thus indicating the necessity for additional cues. Genetic ablation of either a female's CHC pheromones or those of their mate results in loss of ability of mated females to attract other females. We conclude that mated females use a pheromonal marking system, comprising cVA acquired from male ejaculate with sex- and species-specific CHCs produced by both mates, to indicate egg-laying sites. This system ensures information reliability because mated, but not virgin, females have both the ability to generate the pheromone blend that attracts other flies to those sites and a direct interest in egg-laying site quality.

Personality differentially affects individual mate choice decisions in female and male Western mosquitofish (Gambusia affinis).

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Chen, Bo-Jian; Liu, Kai; Zhou, Lin-Jun; Gomes-Silva, Guilherme; Sommer-Trembo, Carolin; Plath, Martin

2018-01-01

Consistent individual differences in behavioral tendencies (animal personality) can affect individual mate choice decisions. We asked whether personality traits affect male and female mate choice decisions similarly and whether potential personality effects are consistent across different mate choice situations. Using western mosquitofish (Gambusia affinis) as our study organism, we characterized focal individuals (males and females) twice for boldness, activity, and sociability/shoaling and found high and significant behavioral repeatability. Additionally, each focal individual was tested in two different dichotomous mate choice tests in which it could choose between computer-animated stimulus fish of the opposite sex that differed in body size and activity levels, respectively. Personality had different effects on female and male mate choice: females that were larger than average showed stronger preferences for large-bodied males with increasing levels of boldness/activity (i.e., towards more proactive personality types). Males that were larger than average and had higher shoaling tendencies showed stronger preferences for actively swimming females. Size-dependent effects of personality on the strength of preferences for distinct phenotypes of potential mating partners may reflect effects of age/experience (especially in females) and social dominance (especially in males). Previous studies found evidence for assortative mate choice based on personality types or hypothesized the existence of behavioral syndromes of individuals' choosiness across mate choice criteria, possibly including other personality traits. Our present study exemplifies that far more complex patterns of personality-dependent mate choice can emerge in natural systems.

'A mate or a meal' – Pre-gravid behaviour of female Anopheles gambiae from the islands of São Tomé and Príncipe, West Africa

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Ferreira Conceicao

2003-05-01

insects was lower than other size groups, but the overall size distribution of each age group was normal. Parous insects were gonotrophically concordant. Conclusion Differences in mosquito survival contributed to the lower sporozoite rates and endemicity of malaria on Príncipe compared to São Tomé. On both islands all newly emerged insects blood fed on the second night following emergence but only became gonotrophically active on the third night after emergence. Smaller insects had a higher 'mortality/emigration' rate than larger ones. We suggest that insufficiency of Juvenile Hormone until the third day of adult life is responsible for gonotrophic inactivity and that by partitioning mating between the second or third day after emergence females maximise their chances of out-crossing.

Reproductive and Productive Performance of Iraqi Buffaloes as Influenced by Pre-Mating and Pre-Calving Concentrate Supplementation

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Talal Anwer Abdulkareem*, Sawsan Ali Al-Sharifi, Sajeda Mahdi Eidan and R.G. Sasser1

2012-06-01

Full Text Available The objective of the present study was to investigate the influence of pre-mating and pre-calving concentrate supplementation of Iraqi buffaloes on some of the reproductive (estrus, mating, pregnancy and calving rates and productive (daily milk yield and calves birth weight traits. This study was carried out in 4 Iraqi South-central governorates using 596 pre-mating and 628 pregnant buffaloes (during the last two months of gestation. Pre-mating buffaloes were divided randomly into 496 concentrate-supplemented buffaloes (Flushing and 100 control ones. Additionally, pregnant buffaloes were also divided into 528 concentrate- supplemented buffaloes (Steaming up and 100 controls. Each buffalo within the flushing and steaming up groups were fed daily on 7 Kg of concentrate diet (13% crude protein and 1.70 Mcal of net energy for 60 days. The control buffaloes were nourished only on low-quality roughages of the area and wheat bran. Higher estrus (+15%, P<0.01, pregnancy (+23.8%, P<0.05 and calving rates (+30.8%, P<0.01 were observed in concentrate-supplemented buffaloes as compared with controls. An obvious increase in (P<0.05 calving rate (+14.7%, daily milk yield (+44.8% and calf birth weight (+25.6% were noted in steaming up buffaloes in comparison with control buffaloes. Results indicated that improvement in feeding schedule of Iraqi buffaloes during pre-mating and late gestation periods enhanced the reproductive performance and increased milk production of subsequent lactation and calf birth weight. These improvements increased owner income ($174=209,000 Iraqi dinar /buffalo from the sale of meat and milk.

Paternity of offspring in multiply-mated, female crickets: the effect of nuptial food gifts and the advantage of mating first

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Calos, J. B.; Sakaluk, S. K.

1998-01-01

The spermatophore transferred by male decorated crickets (Gryllodes sigillatus) includes a large gelatinous mass, the spermatophylax, that is consumed by the female after mating. This nuptial gift preoccupies the female while sperm are discharged from the remaining portion of the spermatophore, the sperm ampulla, into her reproductive tract. There is considerable variation in the mass of the spermatophylax, and about half of all males produce spermatophylaxes that are too small to ensure complete sperm transfer. We tested two hypotheses concerning the maintenance of this variation: (i) males trade-off investment in spermatophylaxes against copulation frequency; and (ii) males synthesize the largest spermatophylaxes of which they are physiologically capable. Males synthesizing large and small food gifts were permitted multiple mating opportunities with the same females, and allozyme markers were used to establish the paternity of offspring. There was a significant advantage to those males that mated first irrespective of gift size. This advantage probably arose, in part, because the sperm of first males would have had exclusive access to females' eggs during the first 24 hours of oviposition, and underscores the benefits of matings with virgin females. The paternity of 'small-gift' males increased with gift mass, but there was no such increase in 'large-gift' males. This difference probably stems from the relationship between gift mass and sperm transfer: most of the gifts of the large-gift males would have been above the threshold needed to achieve complete inseminations, whereas those of small-gift males would have been below the threshold. Within mating-order positions, there was no significant difference in the paternity of large-gift and small-gift males, a result seemingly consistent with the 'trade-off' hypothesis. However, there was no correlation between spermatophylax mass and male mating frequency, so that the mechanism by which small-gift males offset

Mating behaviour of Pseudodiaptomus annandalei (Copepoda Calanoida) with emphasis on rejection rate

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Dur, G.; Souissi, S.; Schmitt, F. G.; Hwang, J. S.; Cheng, S. H.

2009-04-01

Mating behaviour has important consequences at both individual and population levels. Reproductive fitness is of paramount importance to sustain the success of planktonic copepod populations in aquatic environments. The calanoid copepod Pseudodiaptomus annandalei has one of the largest geographical ranges for Indo-Pacific Pseudodiaptomidae. It is also of great importance in fish culture pounds south of Taiwan. However, the mating behavior of this species has never been studied. Mating and predatory behaviour are conceptually the same. In both cases, the encounter and the interactions occur between two individuals with opposite characteristics: predator-prey for predation; male-female for mating. The mating behaviour may be defined as a sequence of encounter, pursuit, capture and copulation. Several observed behaviour suggest that both sexes asses and choose among available mates before the copulation. Pre-copulatory mate choice in copepods may manifest as mate guarding where males attached to CV females until their final moult, complicated pre-copulatory dance and escaping. During our preliminary observations, we notice that P. annandalei females escape by shaking, often violently, the males that have caught them. Consequently for such a species the act of mating may be visualized as a chain of six events (i.e. search, encounter, pursuit, capture, selective dance, copulation).Within this chain, encounter, capture and copulation are conditional events depending on the successful conclusion of their preceding events in the chain. In this study, we examined the different step in the mating behaviour of the scarcely studied sub-tropical copepod, Pseudodiaptomus annandalei, collected from the Danshuei estuary (North Taiwan). The individuals were observed using a 3D optical system to obtain simultaneous front and side views. Males, when placed in the water where females had previously swum in, showed significant increase of their swimming velocities. Additionally, their

The mating behavior of Iguana iguana

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Rodda, G.H.

1992-01-01

Over a 19 month period I observed the social behaviors of individually recognized green iguanas, Iguana iguana, at three sites in the llanos of Venezuela. The behavior of iguanas outside the mating season differed from that seen during the mating season in three major ways: (1) during normal waking hours outside the breeding season, adult iguanas spent the majority of time immobile, apparently resting; (2) their interactions involved fewer high intensity displays; and (3) their day to day movements were often nomadic. During the mating season, one site was watched continuously during daylight hours (iguanas sleep throughout the night), allowing a complete count of all copulation attempts (N = 250) and territorial interactions. At all sites, dominant males controlled access to small mating territories. Within the territories there did not appear to be any resources needed by females or their offspring. Thus, females could choose mates directly on the basis of male phenotype. Females aggregated in the mating territories of the largest males and mated preferentially with them. Territorial males copulated only once per day, although on several occasions more than one resident female was receptive on the same day. A few small nonterritorial males exhibited pseudofemale behavior (i.e., they abstained from sexual competition), but most nonterritorial males stayed on the periphery of mating territories and attempted to force copulations on unguarded females (peripheral male behavior). Uncooperative females were mounted by as many as three males simultaneously. Females resisted 95% of the 200 observed mating attempts by peripheral males, but only 56% of the attempts by territorial males (N = 43). The selectivity of the females probably increased the genetic representation of the territorial males in the next generation. During the mating season females maintained a dominance hierarchy among themselves. Low ranked females tended to be excluded from preferred

Male but not female olfaction is crucial for intermolt mating in European lobsters (Homarus gammarus L.).

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Skog, Malin

2009-02-01

Chemical signals are common in most crustacean social interactions and are often perceived via chemosensory (olfactory) organs on the first antenna. Intermolt courtship behaviors and mating were investigated in size-matched pairs of intermolt European lobsters (Homarus gammarus) where the olfactory receptors of either the male or the female were lesioned with distilled water (olfactory ablation) or seawater (control). Matings or advanced male courtship behaviors (mounting and turning) were common in seawater controls and olfactory-ablated females. In contrast, when male olfaction was ablated with distilled water, there was not a single mating, and the only male courtship behaviors seen were a few very brief and unsuccessful mounting attempts. Individual females mated up to 5 times with different males, showing that previously inseminated females were still attractive to males. Thus, male but not female olfaction is crucial for intermolt mating in H. gammarus, indicating the presence of a female sex pheromone during the entire female molt cycle, not only at the time of molting. Female sex discrimination may be based on other cues from the male in combination with typical male behaviors.

Testing the mate-choice hypothesis of the female orgasm: disentangling traits and behaviours

OpenAIRE

Sherlock, James M.; Sidari, Morgan J.; Harris, Emily Ann; Barlow, Fiona Kate; Zietsch, Brendan P.

2016-01-01

Background: The evolution of the female orgasm in humans and its role in romantic relationships is poorly understood. Whereas the male orgasm is inherently linked to reproduction, the female orgasm is not linked to obvious reproductive or survival benefits. It also occurs less consistently during penetrative sex than does the male orgasm. Mate-choice hypotheses posit that the wide variation in female orgasm frequency reflects a discriminatory mechanism designed to select high-quality mates.Ob...

A potential mate influences reproductive development in female, but not male, pine siskins.

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Watts, Heather E; Edley, Bruce; Hahn, Thomas P

2016-04-01

The role of photoperiod in avian reproductive timing has been well studied, and we are increasingly recognizing the roles of other environmental cues such as social cues. However, few studies have evaluated the extent to which males and females of the same species respond similarly to the same type of cue. Moreover, previous studies have rarely examined how variation in the quality or nature of a given social cue might modulate its effect. Here, we examine the sensitivity of male and female pine siskins (Spinus pinus) to a potential mate as a stimulatory cue for gonadal recrudescence, and we investigate whether variation in the relationship between a bird and its potential mate modulates the effect of that potential mate. Birds were initially housed without opposite sex birds on a 12L:12D photoperiod with ad libitum food. After gonadal recrudescence had begun males and females were randomly paired with an opposite sex bird or housed alone. An additional group of males was paired with estradiol-implanted females. In males, these social treatments had no effect on testis length, cloacal protuberance length, luteinizing hormone (LH) levels, or testosterone levels. In females, presence of a potential mate had a significant and positive effect on ovary score, defeathering of the brood patch, and LH levels. Among paired birds, the degree of affiliation within a pair corresponded to the extent of reproductive development in females, but not males. Thus, reproductive timing in females appears to be sensitive to both the presence of a potential mate and her relationship with him. Copyright © 2016 Elsevier Inc. All rights reserved.

Female brain size affects the assessment of male attractiveness during mate choice.

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Corral-López, Alberto; Bloch, Natasha I; Kotrschal, Alexander; van der Bijl, Wouter; Buechel, Severine D; Mank, Judith E; Kolm, Niclas

2017-03-01

Mate choice decisions are central in sexual selection theory aimed to understand how sexual traits evolve and their role in evolutionary diversification. We test the hypothesis that brain size and cognitive ability are important for accurate assessment of partner quality and that variation in brain size and cognitive ability underlies variation in mate choice. We compared sexual preference in guppy female lines selected for divergence in relative brain size, which we have previously shown to have substantial differences in cognitive ability. In a dichotomous choice test, large-brained and wild-type females showed strong preference for males with color traits that predict attractiveness in this species. In contrast, small-brained females showed no preference for males with these traits. In-depth analysis of optomotor response to color cues and gene expression of key opsins in the eye revealed that the observed differences were not due to differences in visual perception of color, indicating that differences in the ability to process indicators of attractiveness are responsible. We thus provide the first experimental support that individual variation in brain size affects mate choice decisions and conclude that differences in cognitive ability may be an important underlying mechanism behind variation in female mate choice.

Mating-induced changes in olfactory-mediated behavior of laboratory-reared normal, sterile, and wild female Mediterranean fruit flies (Diptera: Tephritidae) mated to conspecific males

International Nuclear Information System (INIS)

Jang, E.B.; McInnis, D.O.; Lance, D.R.; Carvalho, L.A.

1998-01-01

Laboratory-reared normal, sterile, and wild female Mediterranean fruit flies, Ceratitis capitata (Wiedemann), were mated with laboratory-reared normal, sterile, and wild male flies to assess the ability of males to alter olfactory-mediated behavioral responses of females to male-produced pheromone or host fruit odor. Virgin females of all 3 types showed a preferential attraction and arrestment on yellow spheres emitting male-produced pheromone in a laboratory flight tunnel. Laboratory-reared normal and wild females mated to laboratory reared normal, sterile, or wild males switched their behavior showing strong preferential attraction to, arrestment on, and egg-laying in (for laboratory-reared females) yellow spheres emitting host fruit odor (guava) over male-produced pheromone. Sterile females did not show a significant switch in behavior except when mated to sterile males. The olfactory-mediated behavioral switch was most evident in the laboratory-reared normal female × laboratory-reared normal male mating. These findings suggest that irradiation of males inducing gamete sterility does not affect the factor(s) from the male accessory gland associated with altering female olfactory behavior. The ability of sterile males to alter adequately olfactory-mediated behavior of wild females is discussed in the context of the sterile insect technique for control of Mediterranean fruit flies in the field

Mating opportunities in Sangalopsis veliterna females: Costs and benefits

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Hernández Duran, Linda C.; Fajardo Medina, Gonzalo E.; Fuentes Quinter, Luz S.; Martin, Oliver

2014-01-01

Abstract In nature, females of several animal taxa exhibit considerable variation in their mating system, and this variation involves different balances of costs (e.g., energetic, reproductive) and benefits (e.g., increased net reproductive rate of the female, increased longevity). Many studies have focused on discovering the potential advantages and disadvantages that females could have when increasing their mating rate and the possible evolutionary consequences that may result. Butterflies and moths are an ideal study system because it is easy to determine and to manipulate experimentally their mating frequency. In this study, the effect of continuous availability of different numbers of males (1, 2, 4, 8) on female mating rate and fitness components was estimated by comparing the number of spermatophores in the corpus bursa (an estimate of the number of copulations, but not of the number males involved in these copulations), female longevity, lifetime number of laid eggs (fecundity), and proportion of hatching eggs (fertility) in the moth Sangalopsis veliterna Druce (Lepidoptera: Geometridae). The results showed that there were no significant differences in either fertility or fecundity when treatments were compared, but longevity and in some cases fecundity increased when females had several matings. Resumen En la naturaleza, hembras de varios taxa animal muestran una variación considerable en su sistema de apareamiento, esta variación involucra diferentes costos (energéticos, reproductivos, etc) y beneficios (aumento de la tasa reproductiva neta de la hembra, mayor longevidad, entre otros). En años recientes, muchos estudios se han enfocado en descubrir las potenciales ventajas y desventajas que las hembras podrían tener al aumentar su número de cópulas y las posibles consecuencias evolutivas que podrían resultar. Las mariposas y polillas son un sistema de estudio ideal, dada la facilidad para determinar y manipular experimentalmente su frecuencia de

A pair choice test to identify female mating patterns in relation to ovulation in long-tailed macaques (Macaca fascicularis)

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Nikitopoulos, E.; Heistermann, M.; Vries, Han de; Hooff, J.A.R.A.M. van; Sterck, E.H.M.

2005-01-01

Female mammals may exert choice for mates directly by mating selectively. Alternatively, females can mate promiscuously, allowing sperm competition and/or cryptic female choice to operate. Primate sexual behaviour is probably a compromise between conflicting male and female interests, so it may be

Mating rate influences female reproductive investment in a simultaneous hermaphrodite, Lymnaea stagnalis.

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Hoffer, J.N.A.; Schwegler, D.; Ellers, J.; Koene, J.M.

2012-01-01

Multiple mating often imposes direct fitness costs on females but can provide indirect benefits such as enhanced genetic diversity and offspring quality. The costs and benefits of multiple mating have been investigated extensively in separate-sex species but less so in simultaneous hermaphrodites,

Conspicuous female ornamentation and tests of male mate preference in threespine sticklebacks (Gasterosteus aculeatus.

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Daniel Shane Wright

Full Text Available Sexual selection drives the evolution of exaggerated male ornaments in many animal species. Female ornamentation is now acknowledged also to be common but is generally less well understood. One example is the recently documented red female throat coloration in some threespine stickleback (Gasterosteus aculeatus populations. Although female sticklebacks often exhibit a preference for red male throat coloration, the possibility of sexual selection on female coloration has been little studied. Using sequential and simultaneous mate choice trials, we examined male mate preferences for female throat color, as well as pelvic spine color and standard length, using wild-captured threespine sticklebacks from the Little Campbell River, British Columbia. In a multivariate analysis, we found no evidence for a population-level mate preference in males, suggesting the absence of directional sexual selection on these traits arising from male mate choice. Significant variation was detected among males in their preference functions, but this appeared to arise from differences in their mean responsiveness across mating trials and not from variation in the strength (i.e., slope of their preference, suggesting the absence of individual-level preferences as well. When presented with conspecific intruder males, male response decreased as intruder red throat coloration increased, suggesting that males can discriminate color and other aspects of phenotype in our experiment and that males may use these traits in intrasexual interactions. The results presented here are the first to explicitly address male preference for female throat color in threespine sticklebacks.

Conspicuous female ornamentation and tests of male mate preference in threespine sticklebacks (Gasterosteus aculeatus).

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Wright, Daniel Shane; Pierotti, Michele E R; Rundle, Howard D; McKinnon, Jeffrey S

2015-01-01

Sexual selection drives the evolution of exaggerated male ornaments in many animal species. Female ornamentation is now acknowledged also to be common but is generally less well understood. One example is the recently documented red female throat coloration in some threespine stickleback (Gasterosteus aculeatus) populations. Although female sticklebacks often exhibit a preference for red male throat coloration, the possibility of sexual selection on female coloration has been little studied. Using sequential and simultaneous mate choice trials, we examined male mate preferences for female throat color, as well as pelvic spine color and standard length, using wild-captured threespine sticklebacks from the Little Campbell River, British Columbia. In a multivariate analysis, we found no evidence for a population-level mate preference in males, suggesting the absence of directional sexual selection on these traits arising from male mate choice. Significant variation was detected among males in their preference functions, but this appeared to arise from differences in their mean responsiveness across mating trials and not from variation in the strength (i.e., slope) of their preference, suggesting the absence of individual-level preferences as well. When presented with conspecific intruder males, male response decreased as intruder red throat coloration increased, suggesting that males can discriminate color and other aspects of phenotype in our experiment and that males may use these traits in intrasexual interactions. The results presented here are the first to explicitly address male preference for female throat color in threespine sticklebacks.

Males and females contribute unequally to offspring genetic diversity in the polygynandrous mating system of wild boar.

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Javier Pérez-González

Full Text Available The maintenance of genetic diversity across generations depends on both the number of reproducing males and females. Variance in reproductive success, multiple paternity and litter size can all affect the relative contributions of male and female parents to genetic variation of progeny. The mating system of the wild boar (Sus scrofa has been described as polygynous, although evidence of multiple paternity in litters has been found. Using 14 microsatellite markers, we evaluated the contribution of males and females to genetic variation in the next generation in independent wild boar populations from the Iberian Peninsula and Hungary. Genetic contributions of males and females were obtained by distinguishing the paternal and maternal genetic component inherited by the progeny. We found that the paternally inherited genetic component of progeny was more diverse than the maternally inherited component. Simulations showed that this finding might be due to a sampling bias. However, after controlling for the bias by fitting both the genetic diversity in the adult population and the number of reproductive individuals in the models, paternally inherited genotypes remained more diverse than those inherited maternally. Our results suggest new insights into how promiscuous mating systems can help maintain genetic variation.

The evolution of sex differences in mate searching when females benefit: new theory and a comparative test.

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McCartney, J; Kokko, H; Heller, K-G; Gwynne, D T

2012-03-22

Sexual selection is thought to have led to searching as a profitable, but risky way of males obtaining mates. While there is great variation in which sex searches, previous theory has not considered search evolution when both males and females benefit from multiple mating. We present new theory and link it with data to bridge this gap. Two different search protocols exist between species in the bush-cricket genus Poecilimon (Orthoptera): females search for calling males, or males search for calling females. Poecilimon males also transfer a costly nuptial food gift to their mates during mating. We relate variations in searching protocols to variation in nuptial gift size among 32 Poecilimon taxa. As predicted, taxa where females search produce significantly larger nuptial gifts than those where males search. Our model and results show that search roles can reverse when multiple mating brings about sufficiently strong material benefits to females.

Sex roles and mutual mate choice matter during mate sampling.

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Myhre, Lise Cats; de Jong, Karen; Forsgren, Elisabet; Amundsen, Trond

2012-06-01

The roles of females and males in mating competition and mate choice have lately proven more variable, between and within species, than previously thought. In nature, mating competition occurs during mate search and is expected to be regulated by the numbers of potential mates and same-sex competitors. Here, we present the first study to test how a temporal change in sex roles affects mating competition and mate choice during mate sampling. Our model system (the marine fish Gobiusculus flavescens) is uniquely suitable because of its change in sex roles, from conventional to reversed, over the breeding season. As predicted from sex role theory, courtship was typically initiated by males and terminated by females early in the breeding season. The opposite pattern was observed late in the season, at which time several females often simultaneously courted the same male. Mate-searching females visited more males early than late in the breeding season. Our study shows that mutual mate choice and mating competition can have profound effects on female and male behavior. Future work needs to consider the dynamic nature of mating competition and mate choice if we aim to fully understand sexual selection in the wild.

Mate Choice Drives Evolutionary Stability in a Hybrid Complex.

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Miguel Morgado-Santos

Full Text Available Previous studies have shown that assortative mating acts as a driver of speciation by countering hybridization between two populations of the same species (pre-zygotic isolation or through mate choice among the hybrids (hybrid speciation. In both speciation types, assortative mating promotes speciation over a transient hybridization stage. We studied mate choice in a hybrid vertebrate complex, the allopolyploid fish Squalius alburnoides. This complex is composed by several genomotypes connected by an intricate reproductive dynamics. We developed a model that predicts the hybrid complex can persist when females exhibit particular mate choice patterns. Our model is able to reproduce the diversity of population dynamic outcomes found in nature, namely the dominance of the triploids and the dominance of the tetraploids, depending on female mate choice patterns and frequency of the parental species. Experimental mate choice trials showed that females exhibit the preferences predicted by the model. Thus, despite the known role of assortative mating in driving speciation, our findings suggest that certain mate choice patterns can instead hinder speciation and support the persistence of hybrids over time without speciation or extinction.

Transmission of chimeric HIV by mating in conventional mice: prevention by pre-exposure antiretroviral therapy and reduced susceptibility during estrus

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Eran Hadas

2013-09-01

Heterosexual transmission accounts for the majority of new human immunodeficiency virus (HIV cases worldwide. The current approach to investigate HIV heterosexual transmission in animals involves application of virus stock to the vaginal surface, a method that does not reproduce the physiological conditions of vaginal intercourse that influence the rate of transmission. We have previously described efficient infection of conventional mice using EcoHIV/NL4-3 and EcoHIV/NDK, chimeric HIV molecular clones constructed to express all HIV structural and regulatory genes except envelope, which is replaced by a rodent-tropic envelope gene. Here we investigated whether EcoHIV/NDK-infected male mice transmit virus to females during coitus, and the sensitivity of this transmission to HIV pre-exposure prophylaxis and the estrus state. Our general approach was to allow mating between EcoHIV/NDK-infected male mice and uninfected females for 1–7 nights. At 1–6 weeks after mating, mice were euthanized and virus burdens were measured by quantitative PCR (qPCR amplification of HIV RNA or DNA in peritoneal macrophages, inguinal lymph node cells, spleen cells or vas deferens, or by ELISA for antibodies to HIV Gag. We found that 70–100% of female mice mated to EcoHIV/NDK-infected males acquired infection. Pericoital treatment of females with either 2′,3′-dideoxcytidine (ddC or tenofovir largely prevented their EcoHIV/NDK infection by mating (P<0.05 and P<0.003, respectively. In males, T cells were dispensable for virus transmission. The rate of EcoHIV/NDK sexual transmission to females in estrus declined sharply (P=0.003 but their infection by injection was unaffected, indicating that the local environment in the female reproductive tract influences susceptibility to HIV. We conclude that this system of EcoHIV/NDK transmission during mouse mating reproduces key features of heterosexual transmission of HIV in humans and can be used to investigate its biology and control.

The role of oxytocin and vasopressin in conditioned mate guarding behavior in the female rat.

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Holley, Amanda; Bellevue, Shannon; Vosberg, Daniel; Wenzel, Kerstin; Roorda, Sieger; Pfaus, James G

2015-05-15

We have shown previously that female rats given their first copulatory experiences with the same male rat display mate guarding behavior in the presence of that male provided a female competitor is also present. Females given access to the familiar male show more Fos induction within regions of the brain that contain oxytocin (OT) and vasopressin (AVP) cell bodies, notably the supraoptic (SON) and paraventricular nuclei (PVN) relative to females given sexual experience with different males. The present experiments examined whether the Fos induction we previously observed within the SON and PVN occurred within OT and/or AVP neurons, and whether exogenous administration of OT or AVP prior to female rats first sexual experience could potentiate the acquisition of mate guarding behavior. Female rats that display conditioned mate guarding had significantly more double-labeled Fos/OT neurons in both SON and PVN, and significantly more Fos/AVP neurons in the PVN. Peripheral administration of OT or AVP prior to their first sexual experience with the familiar male facilitated different aspects of mate guarding: OT augmented affiliative behaviors and presenting responses whereas AVP augmented interference behavior. These results indicate that female rats' first experiences with sexual reward when paired with the same male induce changes to bonding networks in the brain. Moreover peripheral administration of OT or AVP during their first sexual experience can augment different aspects of mate guarding behavior. Copyright © 2015 Elsevier Inc. All rights reserved.

Evidence for a receiver bias underlying female preference for a male mating pheromone in sea lamprey

Science.gov (United States)

Buchinger, Tyler J.; Wang, Huiyong; Li, Weiming; Johnson, Nicholas S.

2013-01-01

Receiver bias models suggest that a male sexual signal became exaggerated to match a pre-existing sensory, perceptual or cognitive disposition of the female. Accordingly, these models predict that females of related taxa possessing the ancestral state of signalling evolved preference for the male trait in a non-sexual context. We postulated that female preference for the male-released bile alcohol mating pheromone, 3 keto petromyzonol sulfate (3kPZS), of the sea lamprey (Petromyzon marinus) evolved as a result of a receiver bias. In particular, we propose that migratory silver lamprey (Ichthyomyzon unicuspis), a basal member of the Petromyzontidae, evolved a preference for 3kPZS released by stream-resident larvae as a means of identifying productive habitat for offspring. Larval silver lamprey released 3kPZS at rates sufficient to be detected by migratory lampreys. Females responded to 3kPZS by exhibiting upstream movement behaviours relevant in a migratory context, but did not exhibit proximate behaviours important to mate search and spawning. Male silver lamprey did not release 3kPZS at rates sufficient to be detected by females in natural high-volume stream environments. We infer that female silver lamprey cue onto 3kPZS excreted by stream-resident larvae as a mechanism to locate habitat conducive to offspring survival and that males do not signal with 3kPZS. We suggest that this female preference for a male signal in a non-sexual context represents a bias leading to the sexual signalling observed in sea lamprey.

Why Are Males Bad for Females? Models for the Evolution of Damaging Male Mating Behavior

NARCIS (Netherlands)

Lessells, C.M.

2005-01-01

One explanation for the cost to mating for females caused by damaging male mating behavior is that this causes the females to adaptively modify their subsequent life histories in a way that also increases male fitness. This might occur because the reduction in residual reproductive value of the

Females paired with new and heavy mates reduce intra-clutch differences in resource allocation.

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Maud Poisbleau

Full Text Available Reproductive investment affects both offspring and parental fitness and influences the evolution of life histories. Females may vary their overall primary reproductive effort in relation to the phenotypic characteristics of their mate. However, the effects of male quality on differential resource allocation within clutches have been largely neglected despite the potential implications for mate choice and population dynamics, especially in species exhibiting biparental care and brood reduction. Female southern rockhopper penguins Eudyptes chrysocome paired with heavy mates reduced intra-clutch variation in egg and albumen masses. Females paired with new mates also reduced intra-clutch variation in yolk androgen levels. Since both an increased mass and increased androgen concentrations positively influence chick survival under sibling competition, the chances of fledging the whole clutch are likely to be higher for newly formed pairs with heavy males than for previously formed pairs with light males. Interestingly, total clutch provisioning did not vary with male quality. We show for the first time that females vary intra-clutch variation in resource allocation according to male quality. In species with brood reduction, it may be more adaptive for females to modulate the distribution of resources within the clutch according to breeding conditions, than to change their total clutch provisioning.

When not to copy: female fruit flies use sophisticated public information to avoid mated males

Science.gov (United States)

Loyau, Adeline; Blanchet, Simon; van Laere, Pauline; Clobert, Jean; Danchin, Etienne

2012-10-01

Semen limitation (lack of semen to fertilize all of a female's eggs) imposes high fitness costs to female partners. Females should therefore avoid mating with semen-limited males. This can be achieved by using public information extracted from watching individual males' previous copulating activities. This adaptive preference should be flexible given that semen limitation is temporary. We first demonstrate that the number of offspring produced by males Drosophila melanogaster gradually decreases over successive copulations. We then show that females avoid mating with males they just watched copulating and that visual public cues are sufficient to elicit this response. Finally, after males were given the time to replenish their sperm reserves, females did not avoid the males they previously saw copulating anymore. These results suggest that female fruit flies may have evolved sophisticated behavioural processes of resistance to semen-limited males, and demonstrate unsuspected adaptive context-dependent mate choice in an invertebrate.

Female behaviour and the interaction of male and female genital traits mediate sperm transfer during mating.

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Friesen, C R; Uhrig, E J; Mason, R T; Brennan, P L R

2016-05-01

Natural selection and post-copulatory sexual selection, including sexual conflict, contribute to genital diversification. Fundamental first steps in understanding how these processes shape the evolution of specific genital traits are to determine their function experimentally and to understand the interactions between female and male genitalia during copulation. Our experimental manipulations of male and female genitalia in red-sided garter snakes (Thamnophis sirtalis parietalis) reveal that copulation duration and copulatory plug deposition, as well as total and oviductal/vaginal sperm counts, are influenced by the interaction between male and female genital traits and female behaviour during copulation. By mating females with anesthetized cloacae to males with spine-ablated hemipenes using a fully factorial design, we identified significant female-male copulatory trait interactions and found that females prevent sperm from entering their oviducts by contracting their vaginal pouch. Furthermore, these muscular contractions limit copulatory plug size, whereas the basal spine of the male hemipene aids in sperm and plug transfer. Our results are consistent with a role of sexual conflict in mating interactions and highlight the evolutionary importance of female resistance to reproductive outcomes. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Differential effects of male nutrient balance on pre- and post-copulatory traits, and consequences for female reproduction in Drosophila melanogaster

Science.gov (United States)

Morimoto, Juliano; Wigby, Stuart

2016-01-01

Male fitness depends on the expression of costly traits involved in obtaining mates (pre-copulatory) and fertilization (post-copulatory). However, very little is known about the nutrient requirements for these traits and whether males compromise their diet to maximize one trait at the expense of another. Here we used Nutritional Geometry to investigate macronutrient requirements for pre- and post-copulatory traits in Drosophila, when males were the first or second to mate with females. We found no significant effects of male diet on sperm competitiveness. However, although males self-regulate their macronutrient intake at a protein-to-carbohydrate ratio (“P:C ratio”) of 1:1.5, this ratio does not coincide with their optima for several key reproductive traits: both the short-term (~24 hr) rate of offspring production after a female’s first mating, as well as the total offspring number sired when males were second to mate were maximized at a P:C ratio of 1:9, whereas male attractiveness (latency to mate), were maximised at a P:C ratio of 1:1. These results suggest a compromised optimum diet, and no single diet that simultaneously maximizes all male reproductive traits. The protein intake of first males also negatively affected female offspring production following remating, suggesting a long-term intersexual effect of male nutrition. PMID:27270223

Neuropeptides affecting the transfer of juvenile hormones from males to females during mating in Spodoptera frugiperda.

Science.gov (United States)

Hassanien, Intisar T E; Grötzner, Manuela; Meyering-Vos, Martina; Hoffmann, Klaus H

2014-07-01

In the polyandric moth, Spodopterafrugiperda, juvenile hormone (JH) is transferred from the male accessory reproductive glands (AG) to the female bursa copulatrix (BC) during copulation (see Hassanien et al., 2014). Here we used the RNA interference technique to study the role of allatoregulating neuropeptides in controlling the synthesis and transfer of JH during mating. Knockdown of S. frugiperda allatostatin C (Spofr-AS type C) in freshly emerged males leads to an accumulation of JH in the AG beyond that in the control and mating results in a higher transport of JH I and JH II into the female BC. Knockdown of S. frugiperda allatotropin 2 (Spofr-AT2) significantly reduces the amount of JH in the AG as well as its transfer into the female BC during copulation. Knockdown of S. frugiperda allatostatin A (Spofr-AS type A) and S. frugiperda allatotropin (Spofr-AT; Hassanien et al., 2014) only slightly affects the accumulation of JH in the AG and its transfer from the male to the female. We conclude that Spofr-AS type C and Spofr-AT2 act as true allatostatin and true allatotropin, respectively, on the synthesis of JH I and JH II in the male AG. Moreover, both peptides seem to control the synthesis of JH III in the corpora allata of adult males and its release into the hemolymph. Copyright © 2014 Elsevier Ltd. All rights reserved.

Evaluation of mating behaviour and mating compatibility methods for the Old World screwworm fly, Chrysomya bezziana.

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April H. Wardhana

2013-12-01

Full Text Available The effectiveness of the Sterile Insect Technique program (SIT to eradicate pest insects relies on the success of mating competitiveness between irradiated male flies and wild type males for the wild type females. It has been successfully applied for the New World screwworm fly (NWSF, Cochliomyia hominivorax but remains unproven for the Old World screwworm fly (OWSF, Chrysomya bezziana. The aim of the study was to develop methods for investigating mating behaviour and mating compatibility of C. bezziana under laboratory conditions. Two methods were used for studying mating: individual mating (method 1 and group mating (method 2. The flies used in this study were 5-7 days old. Twenty four hours after emergence, adult flies were sexed and placed into different cages until studied. The female : male ratio in the group mating was 1 : 5 and the males were marked by painting a dot on the thorax using different oil colours. Observation of mating behaviour was investigated every 30 minutes through 10-20 replications for all methods depending on the availability of flies. Data were analysed using ANOVA and the Student’s t-test, with significance demonstrated at the 95% confidence level. The results demonstrated that the frequency of contacts between males and females at different ages was a significantly different (p 0.05 and method 2 (p > 0.05. Copulation was only initiated following longer periods of contact, mainly in the range of 270-449 seconds. The highest frequency of copulation occurred between 7-8 days, but the duration of mating was similar between 5-8 days old. The study demonstrated that the methods developed were suitable for a mating compatibility study of C. bezziana.

Yes, I am ready now: differential effects of paced versus unpaced mating on anxiety and central oxytocin release in female rats.

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Kewir D Nyuyki

Full Text Available Sexual activity and partner intimacy results in several positive consequences in the context of stress-coping, both in males and females, such as reduced state anxiety in male rats after successful mating. However, in female rats, mating is a rewarding experience only when the estrous female is able to control sexual interactions, i.e., under paced-mating conditions. Here, we demonstrate that sex-steroid priming required for female mating is anxiolytic; subsequent sexual activity under paced mating conditions did not disrupt this anxiolytic priming effect, whereas mating under unpaced conditions increased anxiety-related behavior. In primed females, the release of the neuropeptide oxytocin (OT within the hypothalamic paraventricular nucleus was found to be elevated and to further increase during paced, but not unpaced mating. Central administration of an OT receptor antagonist partly prevented priming/mating-induced anxiolysis indicating the involvement of brain OT in the anxiolysis triggered by priming and/or sexual activity.These findings reveal that the positive consequences of mating in females are dependent on her ability to control sexual interactions, and that brain OT release is at least in part the underlying neurobiological correlate.

Male mate choice scales female ornament allometry in a cichlid fish

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Kullmann Harald

2010-10-01

Full Text Available Abstract Background Studies addressing the adaptive significance of female ornamentation have gained ground recently. However, the expression of female ornaments in relation to body size, known as trait allometry, still remains unexplored. Here, we investigated the allometry of a conspicuous female ornament in Pelvicachromis taeniatus, a biparental cichlid that shows mutual mate choice and ornamentation. Females feature an eye-catching pelvic fin greatly differing from that of males. Results We show that allometry of the female pelvic fin is scaled more positively in comparison to other fins. The pelvic fin exhibits isometry, whereas the other fins (except the caudal fin show negative allometry. The size of the pelvic fin might be exaggerated by male choice because males prefer female stimuli that show a larger extension of the trait. Female pelvic fin size is correlated with individual condition, suggesting that males can assess direct and indirect benefits. Conclusions The absence of positive ornament allometry might be a result of sexual selection constricted by natural selection: fins are related to locomotion and thus may be subject to viability selection. Our study provides evidence that male mate choice might scale the expression of a female sexual ornament, and therefore has implications for the understanding of the relationship of female sexual traits with body size in species with conventional sex-roles.

Embryonic origin of mate choice in a lizard with temperature-dependent sex determination.

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Putz, Oliver; Crews, David

2006-01-01

Individual differences in the adult sexual behavior of vertebrates are rooted in the fetal environment. In the leopard gecko (Eublepharis macularius), a species with temperature-dependent sex determination (TSD), hatchling sex ratios differ between incubation temperatures, as does sexuality in same-sex animals. This variation can primarily be ascribed to the temperature having direct organizing actions on the brain. Here we demonstrate that embryonic temperature can affect adult mate choice in the leopard gecko. Given the simultaneous choice between two females from different incubation temperatures (30.0 and 34.0 degrees C), males from one incubation temperature (30.0 degrees C) preferred the female from 34.0 degrees C, while males from another incubation temperature (32.5 degrees C) preferred the female from 30.0 degrees C. We suggest that this difference in mate choice is due to an environmental influence on brain development leading to differential perception of opposite-sex individuals. This previously unrecognized modulator of adult mate choice lends further support to the view that mate choice is best understood in the context of an individual's entire life-history. Thus, sexual selection results from a combination of the female's as well as the male's life history. Female attractiveness and male choice therefore are complementary. Copyright 2005 Wiley Periodicals, Inc.

Testing the mate-choice hypothesis of the female orgasm: disentangling traits and behaviours.

Science.gov (United States)

Sherlock, James M; Sidari, Morgan J; Harris, Emily Ann; Barlow, Fiona Kate; Zietsch, Brendan P

2016-01-01

The evolution of the female orgasm in humans and its role in romantic relationships is poorly understood. Whereas the male orgasm is inherently linked to reproduction, the female orgasm is not linked to obvious reproductive or survival benefits. It also occurs less consistently during penetrative sex than does the male orgasm. Mate-choice hypotheses posit that the wide variation in female orgasm frequency reflects a discriminatory mechanism designed to select high-quality mates. We aimed to determine (1) whether women report that their orgasm frequency varies between partners, (2) whether this variation reflects mates' personal characteristics, and (3) whether this variation reflects own and partner sexual behaviour during intercourse. We collected survey data from 103 women who rated (1) the extent to which their orgasm frequency varied between partners, (2) the characteristics of previous sexual partners who induced high-orgasm frequency and those who induced low-orgasm frequency, and (3) the specific behaviours during sex with those partners. This is the first study to test within-woman variation in orgasm and partner traits. Overall, women reported variation in their orgasm rates with different partners. Partners who induced high-orgasm rates were rated as more humorous, creative, warm, faithful, and better smelling than partners who induced low-orgasm rates, and also engaged in greater efforts to induce partner orgasm. Some assumptions and predictions of mate-choice hypotheses of female orgasm were supported, while other aspects of our findings provide reasons to remain sceptical.

Sterility and mating competitiveness of male ceratitis capitata as affected by gamma radiation and di methane insecticide. Vol. 4

Energy Technology Data Exchange (ETDEWEB)

Wakid, A M; Fadel, A M; El-Akhdar, E A [Radiobiology Department, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt); Helmy, N M [Entomology Department, Faculty of Science, Zagazig University, Benha, (Egypt)

1996-03-01

In the present work, the effects of pupal gamma-irradiation (50, 70, 90 Gy), or adult treatment with dimethoate insecticide (0.93 ppm) on the male sterility and mating competitiveness of the medfly, ceratitis capitata (Wied.) were studied. Results indicated that treatment of the adult medfly with dimethoate had no clear effect on male fertility whether this male mated with treated or normal females. However, gamma irradiation drastically decreased hatch ability of eggs laid by normal or treated (dimethoate) females, when mated with irradiated males all gamma doses. This reduction in egg hatch ability increased increased with increasing gamma dose. Irradiated females did not lay eggs at any of the gamma doses used. At all mating combinations, the male mating competitiveness was decreased especially when irradiated males were confined with treated males for mating with normal or treated females. Results are indicated and discussed in the text. 4 figs.

Females' sampling strategy to comparatively evaluate prospective mates in the peacock blenny Salaria pavo

Science.gov (United States)

Locatello, Lisa; Rasotto, Maria B.

2017-08-01

Emerging evidence suggests the occurrence of comparative decision-making processes in mate choice, questioning the traditional idea of female choice based on rules of absolute preference. In such a scenario, females are expected to use a typical best-of- n sampling strategy, being able to recall previous sampled males based on memory of their quality and location. Accordingly, the quality of preferred mate is expected to be unrelated to both the number and the sequence of female visits. We found support for these predictions in the peacock blenny, Salaria pavo, a fish where females have the opportunity to evaluate the attractiveness of many males in a short time period and in a restricted spatial range. Indeed, even considering the variability in preference among females, most of them returned to previous sampled males for further evaluations; thus, the preferred male did not represent the last one in the sequence of visited males. Moreover, there was no relationship between the attractiveness of the preferred male and the number of further visits assigned to the other males. Our results suggest the occurrence of a best-of- n mate sampling strategy in the peacock blenny.

Mating Frequency and Effects on Sex Ratio in Female Parasitoids of xanthopimpla Stemmator (Thunberg). Implications in biological control Programmes

International Nuclear Information System (INIS)

Gitau, C.W.

2002-01-01

Cereals, especially maize and sorghum are the most important field crops in Africa. classical biological Control is a management strategy that employs natural enemies against exotic pests on cereal crops. The method has been used against Chilo partellus (Swinhoe) (Lepidoptera: Crambidae), an introduced pest of maize, using the larval parasitoid cotesia flavipes (Cameron). However, C. flavipes is not able to attack all stem borer species in targeted areas. to complement its work, Xanthopimpla stemmator has successfully been established in Mauritius on Chilo sacchariphagus (Bojer). It is a common phenomenon for haplo-diploid parasitoids to give rise to male progeny when insemination does not take place. Mating becomes important to the parasitoid population since a male biased sex ratio can bring about collapse of the population. The aim of this study was to determine wether xanthopimpla stemmator females mat more than once and wether sex ratio of progeny is affected by multiple mating in female X. stemmator. The female showed a tendency to mate once. Multiple mating did not have any significant effect on either sex ratio or longevity. More males were produced in multiple mated females than once mated females.The effect of multiple mating in X. stemmator on sex ratio in relation to biocontrol programmes are discussed

Mate choice for a male carotenoid-based ornament is linked to female dietary carotenoid intake and accumulation

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Toomey Matthew B

2012-01-01

Full Text Available Abstract Background The coevolution of male traits and female mate preferences has led to the elaboration and diversification of sexually selected traits; however the mechanisms that mediate trait-preference coevolution are largely unknown. Carotenoid acquisition and accumulation are key determinants of the expression of male sexually selected carotenoid-based coloration and a primary mechanism maintaining the honest information content of these signals. Carotenoids also influence female health and reproduction in ways that may alter the costs and benefits of mate choice behaviours and thus provide a potential biochemical link between the expression of male traits and female preferences. To test this hypothesis, we manipulated the dietary carotenoid levels of captive female house finches (Carpodacus mexicanus and assessed their mate choice behavior in response to color-manipulated male finches. Results Females preferred to associate with red males, but carotenoid supplementation did not influence the direction or strength of this preference. Females receiving a low-carotenoid diet were less responsive to males in general, and discrimination among the colorful males was positively linked to female plasma carotenoid levels at the beginning of the study when the diet of all birds was carotenoid-limited. Conclusions Although female preference for red males was not influenced by carotenoid intake, changes in mating responsiveness and discrimination linked to female carotenoid status may alter how this preference is translated into choice. The reddest males, with the most carotenoid rich plumage, tend to pair early in the breeding season. If carotenoid-related variations in female choice behaviour shift the timing of pairing, then they have the potential to promote assortative mating by carotenoid status and drive the evolution of carotenoid-based male plumage coloration.

Heat shock suppresses mating and sperm transfer in the rice leaf folder Cnaphalocrocis medinalis.

Science.gov (United States)

Liao, H J; Qian, Q; Liu, X D

2014-06-01

Temperature is a key environmental factor in determining the population size of Cnaphalocrocis medinalis in summer. High temperatures inhibit survival, development and fecundity of this insect. However, biological responses of female and male adults to heat shock, and physiological mechanism of high temperature suppressing population development are still ambiguous. We experimentally tested the impact of heat shock (5 h day-1) on biological traits, spermatogenesis and sperm transfer of adults of C. medinalis. The result showed that heat exposure to 39 and 40 °C for 5 h reduced longevity and copulation frequency of adults, and hatchability of eggs. Immediate survival rate of males was lower than that of females after 3 days of exposure to 41 °C. The oviposition period, copulation frequency, fecundity of adults and hatchability of eggs were significantly lower when male adults were exposed to 40 or 41 °C for 3 days. Heat shock decreased frequency and success rate of mating when males were exposed, and it also resulted in postponement of mating behaviour and prolongation of mating duration as both the female and male adults were exposed. Heat shock did not affect spermatogenesis, but significantly inhibited sperms maturation. Moreover, males could not ejaculate sperm into females during copulation when these male moths received heat shock. Heat shock remarkably suppressed mating behaviour and sperm transfer, which led to a dramatic decline of rice leaf folder populations.

Testing the mate-choice hypothesis of the female orgasm: disentangling traits and behaviours

Directory of Open Access Journals (Sweden)

James M. Sherlock

2016-10-01

Full Text Available Background: The evolution of the female orgasm in humans and its role in romantic relationships is poorly understood. Whereas the male orgasm is inherently linked to reproduction, the female orgasm is not linked to obvious reproductive or survival benefits. It also occurs less consistently during penetrative sex than does the male orgasm. Mate-choice hypotheses posit that the wide variation in female orgasm frequency reflects a discriminatory mechanism designed to select high-quality mates. Objective: We aimed to determine (1 whether women report that their orgasm frequency varies between partners, (2 whether this variation reflects mates' personal characteristics, and (3 whether this variation reflects own and partner sexual behaviour during intercourse. Design: We collected survey data from 103 women who rated (1 the extent to which their orgasm frequency varied between partners, (2 the characteristics of previous sexual partners who induced high-orgasm frequency and those who induced low-orgasm frequency, and (3 the specific behaviours during sex with those partners. This is the first study to test within-woman variation in orgasm and partner traits. Results: Overall, women reported variation in their orgasm rates with different partners. Partners who induced high-orgasm rates were rated as more humorous, creative, warm, faithful, and better smelling than partners who induced low-orgasm rates, and also engaged in greater efforts to induce partner orgasm. Conclusions: Some assumptions and predictions of mate-choice hypotheses of female orgasm were supported, while other aspects of our findings provide reasons to remain sceptical.

The effects of perceived mating opportunities on patterns of reproductive investment by male guppies.

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Luke T Barrett

Full Text Available Males pay considerable reproductive costs in acquiring mates (precopulatory sexual selection and in producing ejaculates that are effective at fertilising eggs in the presence of competing ejaculates (postcopulatory sexual selection. Given these costs, males must balance their reproductive investment in a given mating to optimise their future reproductive potential. Males are therefore expected to invest in reproduction prudently according to the likelihood of obtaining future matings. In this study we tested this prediction by determining whether male reproductive investment varies with expected future mating opportunities, which were experimentally manipulated by visually exposing male guppies (Poecilia reticulata to high or low numbers of females in the absence of competing males. Our experiment did not reveal consistent effects of perceived future mating opportunity on either precopulatory (male mate choice and mating behaviour or postcopulatory (sperm quality and quantity investment. However, we did find that male size and female availability interacted to influence mating behaviour; large males visually deprived of females during the treatment phase became more choosy and showed greater interest in their preferred female than those given continuous visual access to females. Overall, our results suggest males tailor pre- rather than postcopulatory traits according to local female availability, but critically, these effects depend on male size.

Male Seminal Relaxin Contributes to Induction of the Post-mating Cytokine Response in the Female Mouse Uterus

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Danielle J. Glynn

2017-06-01

Full Text Available The hormone relaxin is important in female reproduction for embryo implantation, cardiovascular function, and during labor and lactation. Relaxin is also synthesized in males by organs of the male tract. We hypothesized that relaxin might be one component of seminal plasma responsible for eliciting the female cytokine response induced in the uterus at mating. When recombinant relaxin was injected into the uterus of wild-type (Rln+/+ mice at estrus, it evoked the production of Cxcl1 mRNA and its secreted protein product CXCL1 in four of eight animals. Mating experiments were then conducted using mice with a null mutation in the relaxin gene (Rln−/− mice. qRT-PCR analysis of mRNA expression in wild-type females showed diminished uterine expression of several cytokine and chemokine genes in the absence of male relaxin. Similar differences were also noted comparing Rln−/− and Rln+/+ females mated to wild-type males. Quantification of uterine luminal fluid cytokine content confirmed that male relaxin provokes the production of CXCL10 and CSF3 in Rln+/+ females. Differences were also seen comparing Rln−/− and Rln+/+ females mated with Rln−/− males for CXCL1, CSF3, and CCL5, implying that endogenous relaxin in females might prime the uterus to respond appropriately to seminal fluid at coitus. Finally, pan-leukocyte CD45 mRNA was increased in wild-type matings compared to other combinations, implying that male and female relaxin may trigger leukocyte expansion in the uterus. We conclude that male and/or female relaxin may be important in activating the uterine cytokine/chemokine network required to initiate maternal immune adaptation to pregnancy.

Interdependent effects of male and female body size plasticity on mating behaviour of predatory mites.

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Walzer, Andreas; Schausberger, Peter

2015-02-01

The adaptive canalization hypothesis predicts that traits with low phenotypic plasticity are more fitness relevant, because they have been canalized via strong past selection, than traits with high phenotypic plasticity. Based on differing male body size plasticities of the predatory mites Phytoseiulus persimilis (low plasticity) and Neoseiulus californicus (high plasticity), we accordingly hypothesized that small male body size entails higher costs in female choice and male-male competition in P. persimilis than N. californicus . Males of both species are highly polygynous but females differ in the level of polyandry (low level in P. persimilis ; medium level in N. californicus ). We videotaped the mating interactions in triplets of either P. persimilis or N. californicus , consisting of a virgin female (small or standard-sized) and a small and a standard-sized male. Mating by both small and standard-sized P. persimilis females was biased towards standard-sized males, resulting from the interplay between female preference for standard-sized males and the inferiority of small males in male-male competition. In contrast, mating by N. californicus females was equally balanced between small and standard-sized males. Small N. californicus males were more aggressive ('Napoleon complex') in male-male competition, reducing the likelihood of encounter between the standard-sized male and the female, and thus counterbalancing female preference for standard-sized males. Our results support the hypothesis that male body size is more important to fitness in the low-level polyandrous P. persimilis than in the medium-level polyandrous N. californicus and provide a key example of the implications of sexually selected body size plasticity on mating behaviour.

Chemical and visual communication during mate searching in rock shrimp.

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Díaz, Eliecer R; Thiel, Martin

2004-06-01

Mate searching in crustaceans depends on different communicational cues, of which chemical and visual cues are most important. Herein we examined the role of chemical and visual communication during mate searching and assessment in the rock shrimp Rhynchocinetes typus. Adult male rock shrimp experience major ontogenetic changes. The terminal molt stages (named "robustus") are dominant and capable of monopolizing females during the mating process. Previous studies had shown that most females preferably mate with robustus males, but how these dominant males and receptive females find each other is uncertain, and is the question we examined herein. In a Y-maze designed to test for the importance of waterborne chemical cues, we observed that females approached the robustus male significantly more often than the typus male. Robustus males, however, were unable to locate receptive females via chemical signals. Using an experimental set-up that allowed testing for the importance of visual cues, we demonstrated that receptive females do not use visual cues to select robustus males, but robustus males use visual cues to find receptive females. Visual cues used by the robustus males were the tumults created by agitated aggregations of subordinate typus males around the receptive females. These results indicate a strong link between sexual communication and the mating system of rock shrimp in which dominant males monopolize receptive females. We found that females and males use different (sex-specific) communicational cues during mate searching and assessment, and that the sexual communication of rock shrimp is similar to that of the American lobster, where females are first attracted to the dominant males by chemical cues emitted by these males. A brief comparison between these two species shows that female behaviors during sexual communication contribute strongly to the outcome of mate searching and assessment.

Genetic and educational assortative mating among US adults.

Science.gov (United States)

Domingue, Benjamin W; Fletcher, Jason; Conley, Dalton; Boardman, Jason D

2014-06-03

Understanding the social and biological mechanisms that lead to homogamy (similar individuals marrying one another) has been a long-standing issue across many fields of scientific inquiry. Using a nationally representative sample of non-Hispanic white US adults from the Health and Retirement Study and information from 1.7 million single-nucleotide polymorphisms, we compare genetic similarity among married couples to noncoupled pairs in the population. We provide evidence for genetic assortative mating in this population but the strength of this association is substantially smaller than the strength of educational assortative mating in the same sample. Furthermore, genetic similarity explains at most 10% of the assortative mating by education levels. Results are replicated using comparable data from the Framingham Heart Study.

The Post-mating Switch in the Pheromone Response of Nasonia Females Is Mediated by Dopamine and Can Be Reversed by Appetitive Learning

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Maria Lenschow

2018-01-01

Full Text Available The olfactory sense is of crucial importance for animals, but their response to chemical stimuli is plastic and depends on their physiological state and prior experience. In many insect species, mating status influences the response to sex pheromones, but the underlying neuromodulatory mechanisms are poorly understood. After mating, females of the parasitic wasp Nasonia vitripennis are no longer attracted to the male sex pheromone. Here we show that this post-mating behavioral switch is mediated by dopamine (DA. Females fed a DA-receptor antagonist prior to mating maintained their attraction to the male pheromone after mating while virgin females injected with DA became unresponsive. However, the switch is reversible as mated females regained their pheromone preference after appetitive learning. Feeding mated N. vitripennis females with antagonists of either octopamine- (OA or DA-receptors prevented relearning of the pheromone preference suggesting that both receptors are involved in appetitive learning. Moreover, DA injection into mated females was sufficient to mimic the oviposition reward during odor conditioning with the male pheromone. Our data indicate that DA plays a key role in the plastic pheromone response of N. vitripennis females and reveal some striking parallels between insects and mammals in the neuromodulatory mechanisms underlying olfactory plasticity.

Male Drosophila melanogaster learn to prefer an arbitrary trait associated with female mating status

DEFF Research Database (Denmark)

Verzijden, Machteld Nicolette; Abbott, Jessica K.; Philipsborn, Anne von

2015-01-01

Although males are generally less discriminating than females when it comes to choosing a mate, they still benefit from distinguishing between mates that are receptive to courtship and those that are not, in order to avoid wasting time and energy. It is known that males of Drosophila melanogaster...... color, but that males which were trained with sexually receptive females of a given eye color showed a preference for that color during a standard binary choice experiment. The learned cue was indeed likely to be truly visual, since the preference disappeared when the binary choice phase...

MATE CHOICE IN AIDABLENNIUS-SPHYNX (TELEOSTEI, BLENNIIDAE) - FEMALES PREFER NESTS CONTAINING MORE EGGS

NARCIS (Netherlands)

KRAAK, SBM; VIDELER, JJ

1991-01-01

Criteria for female mate choice were investigated in a natural population of a Mediterranean blenny, Aidablennius sphynx. Removable test tubes in concrete blocks were offered as nests. Each tube was guarded by a male and females laid eggs in the tubes. Nests with larger broods received significantly

Male dominance, female mate choice and intersexual conflict in the rose bitterling (Rhodeus ocellatus)

Czech Academy of Sciences Publication Activity Database

Casalini, M.; Agbali, M.; Reichard, Martin; Konečná, Markéta; Bryjová, Anna; Smith, C.

2009-01-01

Roč. 63, č. 2 (2009), s. 366-376 ISSN 0014-3820 R&D Projects: GA MŠk LC06073; GA AV ČR KJB600930501 Institutional research plan: CEZ:AV0Z60930519 Keywords : female mating preference * good genes * olfactory cues * mate choice * MHC * Rhodeus ocellatus Subject RIV: EG - Zoology Impact factor: 5.429, year: 2009

Gamma irradiation effects on some biological aspects of Ephestia Kuehniella (Zell.), inherited sterility and mating competitiveness

International Nuclear Information System (INIS)

EI-Orabi, M.N.; Sawires, S.G.; Antonious, A.G.; Salama, S.I.

2007-01-01

Full grown male and female pupae of the Mediterranean flour moth, Ephestia kuehniella (Zell.) were exposed to gamma irradiation doses ranging from 40 to 450 Gy. Irradiated males were more radio-resistant than females. Reduction in fecundity and egg hatch were dose-dependant. Irradiated males or females showed significant shorter lifespan than control group. Also, there were reductions in F 1 progeny as a result of irradiating male and female parents with sub-sterilizing doses, which were more apparent in irradiating of male parents. The average larval pupal developmental period of F1 male and female progeny was affected. The sex ratio of F 1 generation was shifted in favor of males. The parental males or females irradiated as full-grown pupae were affected with sub-sterilizing dose of 200 Gy for male line and 100 Gy for female line. All possible mating combinations in F1, F 2 and F3 of males and females lines were examined. Fecundity and fertility of F I adults descendant from irradiated male parents were significantly reduced than F1 adults descendant from irradiated female parents. Also, the number of laid eggs and percentage of egg hatch were reduced drastically in crosses of F 1 males mated to unirradiated females of male line. Fecundity and fertility of the different mating combinations among F2 generation for both male and female treated lines were significantly decreased than the unirradiated control. Also, the number of adults resulting from all mating crosses among F2 generation was greatly reduced as compared to control adult progeny. There was a recovery in reproductive potential in moths of third generation for irradiated male line and in the second generation of the irradiated female line

Sensory Biology: How Female Treefrogs Pick Mates at a Noisy Party.

Science.gov (United States)

Taylor, Ryan C

2017-03-06

A recent study has found that, despite strong acoustic masking from background noise, female treefrogs are able to select among individual males advertising for mates by taking advantage of small, periodic decreases in the overall noise structure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Reinforcement shapes clines in female mate discrimination in Drosophila subquinaria

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Bewick, Emily R.; Dyer, Kelly A.

2014-01-01

Reinforcement of species boundaries may alter mate recognition in a way that also affects patterns of mate preference among conspecific populations. In the fly Drosophila subquinaria, females sympatric with the closely related species D. recens reject mating with heterospecific males as well as with conspecific males from allopatric populations. Here, we assess geographic variation in behavioral isolation within and among populations of D. subquinaria and use cline theory to understand patterns of selection on reinforced discrimination and its consequences for sexual isolation within species. We find that selection has fixed rejection of D. recens males in sympatry, while significant genetic variation in this behavior occurs within allopatric populations. In conspecific matings sexual isolation is also asymmetric and stronger in populations that are sympatric with D. recens. The clines in behavioral discrimination within and between species are similar in shape and are maintained by strong selection in the face of gene flow, and we show that some of their genetic basis may be either shared or linked. Thus, while reinforcement can drive extremely strong phenotypic divergence, the long-term consequences for incipient speciation depend on gene flow, genetic linkage of discrimination traits, and the cost of these behaviors in allopatry. PMID:25163510

Endocrinology of human female sexuality, mating, and reproductive behavior.

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Motta-Mena, Natalie V; Puts, David A

2017-05-01

Hormones orchestrate and coordinate human female sexual development, sexuality, and reproduction in relation to three types of phenotypic changes: life history transitions such as puberty and childbirth, responses to contextual factors such as caloric intake and stress, and cyclical patterns such as the ovulatory cycle. Here, we review the endocrinology underlying women's reproductive phenotypes, including sexual orientation and gender identity, mate preferences, competition for mates, sex drive, and maternal behavior. We highlight distinctive aspects of women's sexuality such as the possession of sexual ornaments, relatively cryptic fertile windows, extended sexual behavior across the ovulatory cycle, and a period of midlife reproductive senescence-and we focus on how hormonal mechanisms were shaped by selection to produce adaptive outcomes. We conclude with suggestions for future research to elucidate how hormonal mechanisms subserve women's reproductive phenotypes. Copyright © 2016 Elsevier Inc. All rights reserved.

Cryptic forcible insemination: male snakes exploit female physiology, anatomy, and behavior to obtain coercive matings.

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Shine, Richard; Langkilde, Tracy; Mason, Robert T

2003-11-01

Whether males can inseminate uncooperative females is a central determinant of mating system evolution that profoundly affects the interpretation of phenomena such as multiple mating by females, mate choice, reproductive seasonality, and courtship tactics. Forcible insemination is usually inferred from direct physical battles between the sexes and has been dismissed on intuitive grounds for many kinds of animals. For example, snakes have elongate flexible bodies (making it difficult for a male to restrain a female physically), males are typically smaller than females, and copulation requires female cloacal gaping to enable intromission. Male garter snakes (Thamnophis sirtalis) do not display any overt aggression during courtship and simply lie over the female and exhibit rhythmic pulsating caudocephalic waves of muscular contraction; previous studies have interpreted this behavior as a mechanism for eliciting female receptivity. In contrast, we show that male garter snakes forcibly inseminate females. They do so by taking advantage of specific features of snake physiology, respiratory anatomy, and antipredator behavior. The snake lung extends along most of the body, with the large posterior section (the saccular lung) lacking any respiratory exchange surface. Rhythmic caudocephalic waves by courting male garter snakes push anoxic air from the saccular lung forward and across the respiratory surfaces such that females cannot obtain oxygen. Their stress response involves cloacal gaping, which functions in other contexts to repel predators by extruding feces and musk but in this situation permits male intromission. Thus, superficially benign courtship behaviors may involve cryptic coercion even in species for which intuition dismisses any possibility of forcible insemination.

An integrative mating system assessment of a nonmodel, economically important Pacific rockfish (Sebastes melanops) reveals nonterritorial polygamy and conservation implications for a large species flock.

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Karageorge, Kurt W; Wilson, Raymond R

2017-12-01

Characterizing the mating systems of long-lived, economically important Pacific rockfishes comprising the viviparous Sebastes species flock is crucial for their conservation. However, direct assignment of mating success to sires is precluded by open, offshore populations and high female fecundity. We addressed this challenge by integrating paternity-assigned mating success of females with the adult sex ratio (ASR) of the population, male evolutionary responses to receptive females, and reproductive life history traits-in the framework of sexual selection theory-to assess the mating system of Sebastes melanops . Microsatellite parentage analysis of 17 pregnant females, 1,256 of their progeny, and 106 adults from the population yielded one to four sires per brood, a mean of two sires, and a female mate frequency distribution with a truncated normal (random) pattern. The 11 multiple paternity broods all contained higher median allele richness than the six single paternity broods (Wilcoxon test: W  = 0, p  distributions that distinguish polygynandry and polyandrogyny mating systems, that is, variations of polygamy, but not polyandry. Inference for polygamy is consistent with weak premating sexual selection on males, expected in mid-water, schooling S. melanops , owing to polyandrous mating, moderately aggregated receptive females, an even ASR, and no territories and nests used for reproduction. Each of these characteristics facilitates more mating males and erodes conspicuous sexual dimorphism. Evaluation of male evolutionary responses of demersal congeners that express reproductively territorial behavior revealed they have more potential mechanisms for producing premating sexual selection, greater variation in reproductive success, and a reduced breeding effective population size of adults and annual effective size of a cohort, compared to S. melanops modeled with two mates per adult. Such divergence in behavior and mating system by territorial species may

Female mating preferences determine system-level evolution in a gene network model.

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Fierst, Janna L

2013-06-01

Environmental patterns of directional, stabilizing and fluctuating selection can influence the evolution of system-level properties like evolvability and mutational robustness. Intersexual selection produces strong phenotypic selection and these dynamics may also affect the response to mutation and the potential for future adaptation. In order to to assess the influence of mating preferences on these evolutionary properties, I modeled a male trait and female preference determined by separate gene regulatory networks. I studied three sexual selection scenarios: sexual conflict, a Gaussian model of the Fisher process described in Lande (in Proc Natl Acad Sci 78(6):3721-3725, 1981) and a good genes model in which the male trait signalled his mutational condition. I measured the effects these mating preferences had on the potential for traits and preferences to evolve towards new states, and mutational robustness of both the phenotype and the individual's overall viability. All types of sexual selection increased male phenotypic robustness relative to a randomly mating population. The Fisher model also reduced male evolvability and mutational robustness for viability. Under good genes sexual selection, males evolved an increased mutational robustness for viability. Females choosing their mates is a scenario that is sufficient to create selective forces that impact genetic evolution and shape the evolutionary response to mutation and environmental selection. These dynamics will inevitably develop in any population where sexual selection is operating, and affect the potential for future adaptation.

Good genes and sexual selection in dung beetles (Onthophagus taurus: genetic variance in egg-to-adult and adult viability.

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Francisco Garcia-Gonzalez

2011-01-01

Full Text Available Whether species exhibit significant heritable variation in fitness is central for sexual selection. According to good genes models there must be genetic variation in males leading to variation in offspring fitness if females are to obtain genetic benefits from exercising mate preferences, or by mating multiply. However, sexual selection based on genetic benefits is controversial, and there is limited unambiguous support for the notion that choosy or polyandrous females can increase the chances of producing offspring with high viability. Here we examine the levels of additive genetic variance in two fitness components in the dung beetle Onthophagus taurus. We found significant sire effects on egg-to-adult viability and on son, but not daughter, survival to sexual maturity, as well as moderate coefficients of additive variance in these traits. Moreover, we do not find evidence for sexual antagonism influencing genetic variation for fitness. Our results are consistent with good genes sexual selection, and suggest that both pre- and postcopulatory mate choice, and male competition could provide indirect benefits to females.

Infants prefer female body phenotypes; infant girls prefer they have an hourglass shape.

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Gerianne M Alexander

2016-06-01

Full Text Available Adolescents and adults show preferences for male and female body shapes consistent with evolutionary theories of reproductive fitness and mate selection. However, when these preferences for females with narrow waists (i.e., 0.7 waist-to-hip ratio and men with broad shoulders (i.e., mesomorphic body shape emerge during the lifespan is largely unknown. To address this knowledge gap, eye-movements were tracked in 144 infants (3 to 18 months of age during computer presentation of three-dimensional human figures varying in body features thought relevant for reproductive success (e.g., secondary sex characteristics, waist-to-hip ratio. When presented with pairs of figures differing in apparent sex, male and female infants looked significantly longer at the female figure compared to the male figure, a new finding that extends previous research showing preferences for female faces in infancy. When presented with same-sex figures differing in characteristics associated with mate value, male and female infants looked longer at a low mate value male (i.e., an endomorphic body type compared to a high mate value male (i.e., a mesomorphic body type, a finding that replicates the results of previous research. In addition, the novel use of high and low mate value female figures showed a sex difference in visual attention, such that female infants looked longer at the high mate value female figure compared to the low mate female figure whereas male infants showed the opposite pattern of results. In sum, these findings suggest that infants generally do not possess preferences for adult-defined attractive male body shapes. However, infant girls’ greater attention to a female figure with an adult-preferred waist-to-hip ratio raises the possibility that evolved preferences for 0.7 waist-to-hip ratio influence girls’ later preference for toys representing females with an hourglass shape, perhaps supporting elaboration of adult social behaviors that enhance

Infants Prefer Female Body Phenotypes; Infant Girls Prefer They Have an Hourglass Shape.

Science.gov (United States)

Alexander, Gerianne M; Hawkins, Laura B; Wilcox, Teresa; Hirshkowitz, Amy

2016-01-01

Adolescents and adults show preferences for male and female body shapes consistent with evolutionary theories of reproductive fitness and mate selection. However, when these preferences for females with narrow waists (i.e., 0.7 waist-to-hip ratio) and men with broad shoulders (i.e., mesomorphic body shape) emerge during the lifespan is largely unknown. To address this knowledge gap, eye-movements were tracked in 146 infants (3-18 months of age) during computer presentation of three-dimensional human figures varying in body features thought relevant for reproductive success (e.g., secondary sex characteristics, waist-to-hip ratio). When presented with pairs of figures differing in apparent sex, male and female infants looked significantly longer at the female figure compared to the male figure, a new finding that extends previous research showing preferences for female faces in infancy. When presented with same-sex figures differing in characteristics associated with mate value, male and female infants looked longer at a low mate value male (i.e., an endomorphic body type) compared to a high mate value male (i.e., a mesomorphic body type), a finding that replicates the results of previous research. In addition, the novel use of high and low mate value female figures showed a sex difference in visual attention, such that female infants looked longer at the high mate value female figure compared to the low mate female figure whereas male infants showed the opposite pattern of results. In sum, these findings suggest that infants generally do not possess preferences for adult-defined attractive male body shapes. However, infant girls' greater attention to a female figure with an adult-preferred waist-to-hip ratio raises the possibility that evolved preferences for 0.7 waist-to-hip ratio influence girls' later preference for toys representing females with an hourglass shape, perhaps supporting elaboration of adult social behaviors that enhance reproductive success (e

Effect of irradiation sterilizing dose on the mating competitiveness of Trogoderma Granarium Everts treated as adults at different ages

International Nuclear Information System (INIS)

Gharieb, O.H.

2002-01-01

Males of Trogoderma Granarium at ages of 1, 3, 5 and 7 days were irradiated with 200 GY (sterilizing dose) and combined with the same ages of the normal males mated with 1-d-old females. (I male : u male : U ) in the fohowing ratios of (1:1:1), (5:1:1), (10:1:1) and (15:1:1). At 15 irradiated males per pair, egg hatch was reduced to 4.5 and 2.2% at male ages of 1 and 3 d-old, respectively, but, it was 4.9 and 7.5 at male ages of 5 and 7 d-old, respectively. The calculated degree of mating competitiveness at this ratio was 1.10, 1.03, 0.97 and 0.94 for the corresponding ages. Females at the aformentioned ages irradiated with 60 GY (sterilizing dose) and competed with normal females for normal males. At 15 irradiated females per pair, the egg hatch was reduced to 5.4, 2.1, 1.8 and 1.4 % for the corresponding ages tested. Therefore, (I) females showed good competitiveness at most release ratios, but (I) females were fully competitive (1.00) at the higher release ratio I:U females (15:1). In general, (I) females were more competitive (based on number of eggs per female and percent infertility) than the corresponding (I) males especially at later ages (5 and 7 d-old adults) even, at the higher release ratios. =

Age Variation in Mating Strategies and Mate Preferences: Beliefs versus Reality

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April Bleske-Rechek

2009-04-01

Full Text Available We conducted three studies to (1 investigate individuals' beliefs about change in mating desires over the course of emerging adulthood and (2 determine whether those beliefs reflect actual variation in mating desires among emerging adults of varied ages (late teens through twenties. In Study 1, 103 men and women gave their thoughts on how college students change, if at all, in what they most desire in a relationship and relationship partner as they move from being incoming freshmen to graduating seniors. In Studies 2 and 3, using a college sample and then an internet sample (n s = 288 and 307, men and women between the ages of 18 and 26 completed mating strategies inventories and allotted a limited number of “mate dollars” to 10 mate characteristics. Findings suggest that although emerging adults believe that their peers' mating desires change systematically over time, emerging adults' self-reported mating desires vary little with age.

Reproductive behavior and physiology of Dacus oleae: egg hatch in females mated successively with normal and gamma sterilized males and vice versa

International Nuclear Information System (INIS)

Economopoulos, A.P.; Giannakakis, A.; Voyadjoglou, A.V.

1976-01-01

In Dacus oleae (Gmelin), a 2nd mating by an 8-krad gamma ray-sterilized male reduced egg hatch immediately to zero or near-zero in ca. 40-55 percent of individually-tested females. In another 50 percent of females, egg hatch was reduced to between 5 to 70 percent, while in fewer than 10 percent of females, egg hatch showed no change. The above was true for females reared on artificial diet for more than 50 generations and mated with same type males, as well as females reared on olives for 6 to 8 generations and mated first with same type males and 2nd with artificially-reared sterilized males. When the 2nd males were treated at 15 krad the effect on egg hatch was smaller. When the 2nd males were treated at 8 krad and had depleted their sperm, by repeated matings, they produced small or no-effect on egg hatch. When artificially-reared females mated first with a sterilized and second with a normal same type male, egg hatch increased from 0 to 5 percent to 70 to 100 percent in 50 to 55 percent of the cases. In another 43 percent of cases, egg hatch increased to levels between 5 to 70 percent. The combined findings from the 2 mating sequence types are as follows. After females mated first with normal males, egg hatch was above 80 percent in the population; a 2nd mating with 8-krad-sterilized males produced an immediate decrease of egg hatch to ca. 25 percent, decreasing slowly thereafter. When the 1st male was sterilized and the 2nd normal, egg hatch increased to ca. 70 percent, decreasing slowly thereafter

Differences in Mating Propensity Between Immature Female Color Morphs in the Damselfly Ischnura elegans (Insecta : Odonata)

NARCIS (Netherlands)

Hammers, Martijn; Ana Sanchez-Guillen, Rosa; Van Gossum, Hans

Female-limited color polymorphisms occur in a variety of animal taxa where excessive male sexual harassment may explain the coexistence of multiple female color morphs. In the color polymorphic damselfly Ischnura elegans, mature and immature female color morphs coexist at the mating site where males

Drosophila male sex peptide inhibits siesta sleep and promotes locomotor activity in the post-mated female.

Science.gov (United States)

Isaac, R Elwyn; Li, Chenxi; Leedale, Amy E; Shirras, Alan D

2010-01-07

Quiescence, or a sleep-like state, is a common and important feature of the daily lives of animals from both invertebrate and vertebrate taxa, suggesting that sleep appeared early in animal evolution. Recently, Drosophila melanogaster has been shown to be a relevant and powerful model for the genetic analysis of sleep behaviour. The sleep architecture of D. melanogaster is sexually dimorphic, with females sleeping much less than males during day-time, presumably because reproductive success requires greater foraging activity by the female as well as the search for egg-laying sites. However, this loss of sleep and increase in locomotor activity will heighten the risk for the female from environmental and predator hazards. In this study, we show that virgin females can minimize this risk by behaving like males, with an extended afternoon 'siesta'. Copulation results in the female losing 70 per cent of day-time sleep and becoming more active. This behaviour lasts for at least 8 days after copulation and is abolished if the mating males lack sex peptide (SP), normally present in the seminal fluid. Our results suggest that SP is the molecular switch that promotes wakefulness in the post-mated female, a change of behaviour compatible with increased foraging and egg-laying activity. The stress resulting from SP-dependent sleep deprivation might be an important contribution to the toxic side-effects of male accessory gland products that are known to reduce lifespan in post-mated females.

Female sticklebacks use male coloration in mate choice and hence avoid parasitized males

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Milinski, Manfred; Bakker, Theo C. M.

1990-03-01

AN important problem in evolutionary biology since the time of Darwin has been to understand why females preferentially mate with males handicapped by secondary sexual ornaments1-3. One hypothesis of sexual selection theory is that these ornaments reliably reveal the male's condition4-6, which can be affected for example by parasites4,7-13. Here we show that in the three-spined stickleback (Gasterosteus aculeatus) the intensity of male red breeding coloration positively correlates with physical condition. Gravid females base their active mate choice on the intensity of the male's red coloration. Choice experiments under green light prevent the use of red colour cues by females, and males that were previously preferred are now chosen no more than randomly, although the courtship behaviour of the males remains unchanged. Parasitieation causes a deterioration in the males' condition and a decrease in the intensity of their red coloration. Tests under both lighting conditions reveal that the females recognize the formerly parasitized males by the lower intensity of their breeding coloration. Female sticklebacks possibly select a male with a good capacity for paternal care14 but if there is additive genetic variation for parasite resistance, then they might also select for resistance genes, as proposed by Hamilton and Zuk4.

Female detection of the synthetic sex pheromone contributes to the efficacy of mating disruption of the European grapevine moth, Lobesia botrana.

Science.gov (United States)

Harari, Ally R; Zahavi, Tirtza; Steinitz, Hadass

2015-02-01

Studies of the mechanisms by which mating-disruption techniques control insect pest populations have traditionally focused on the effects of the species-specific sex pheromone on the male moths, while neglecting possible direct effects of the pheromone on females. Here, the effects of exposure to synthetic species-specific sex-pheromone on Lobesia botrana (European grapevine moth) females were tested. Females in vineyards that were treated with mating-disruption pheromone burst into short bouts of flying more frequently, but called significantly less frequently than females in untreated plots. Reduced calling caused by exposure to the species-specific sex-pheromone may increase the age at which females mate and thereby reduce female fecundity. Females that called in a pheromone-saturated environment experienced a decrease in number of oviposited eggs. A further decrease in reproductive success may occur if females delay oviposition when exposed to access of the synthetic pheromone. In addition to reducing the ability of males to locate females, the mating-disruption technique can suppress pest numbers as a consequence of its direct effects on females. The two mechanisms probably act synergistically. © 2014 Society of Chemical Industry.

Male foraging efficiency, but not male problem-solving performance, influences female mating preferences in zebra finches

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Véronique Chantal

2016-08-01

Full Text Available Experimental evidence suggests that females would prefer males with better cognitive abilities as mates. However, little is known about the traits reflecting enhanced cognitive skills on which females might base their mate-choice decisions. In particular, it has been suggested that male foraging performance could be used as an indicator of cognitive capacity, but convincing evidence for this hypothesis is still lacking. In the present study, we investigated whether female zebra finches (Taeniopygia guttata modify their mating preferences after having observed the performance of males on a problem-solving task. Specifically, we measured the females’ preferences between two males once before and once after an observation period, during which their initially preferred male was incapable of solving the task contrary to their initially less-preferred male. We also conducted a control treatment to test whether the shift in female preferences was attributable to differences between the two stimulus males in their foraging efficiency. Finally, we assessed each bird’s performance in a color associative task to check whether females can discriminate among males based on their learning speed. We found that females significantly increased their preference toward the most efficient male in both treatments. Yet, there was no difference between the two treatments and we found no evidence that females assess male cognitive ability indirectly via morphological traits. Thus, our results suggest that females would not use the males’ problem-solving performance as an indicator of general cognitive ability to gain indirect fitness benefits (i.e., good genes but rather to assess their foraging efficiency and gain direct benefits.

Evaluation of radiation sensitivity and mating performance of Glossina brevipalpis males.

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Chantel J de Beer

2017-03-01

Full Text Available Area-wide integrated pest management strategies that include a sterile insect technique component have been successfully used to eradicate tsetse fly populations in the past. To ensure the success of the sterile insect technique, the released males must be adequately sterile and be able to compete with their native counterparts in the wild.In the present study the radiation sensitivity of colonised Glossina brevipalpis Newstead (Diptera; Glossinidae males, treated either as adults or pupae, was assessed. The mating performance of the irradiated G. brevipalpis males was assessed in walk-in field cages. Glossina brevipalpis adults and pupae were highly sensitive to irradiation, and a dose of 40 Gy and 80 Gy induced 93% and 99% sterility respectively in untreated females that mated with males irradiated as adults. When 37 to 41 day old pupae were exposed to a dose of 40 Gy, more than 97% sterility was induced in untreated females that mated with males derived from irradiated pupae. Males treated as adults with a dose up to 80 Gy were able to compete successfully with untreated fertile males for untreated females in walk-in field cages.The data emanating from this field cage study indicates that, sterile male flies derived from the colony of G. brevipalpis maintained at the Agricultural Research Council-Onderstepoort Veterinary Institute in South Africa are potential good candidates for a campaign that includes a sterile insect technique component. This would need to be confirmed by open field studies.

Comparison of the effects of the mother and an unfamiliar adult female on cortisol and behavioral responses of pre- and postweaning guinea pigs.

Science.gov (United States)

Graves, F C; Hennessy, M B

2000-03-01

In the guinea pig, the presence of the mother, but not littermates, has been found to inhibit hypothalamic-pituitary-adrenal (HPA) responses during brief (30-60 min) exposure to novel surroundings both prior to and several weeks following the completion of weaning. In the present study, we found that an unfamiliar adult female inhibited plasma cortisol and vocalization responses of pre- and postweaning guinea pigs during a 60-min exposure to a novel environment. However, the presence of the mother still had a greater effect on the cortisol levels of the young, at least during the preweaning period. The moderating influence of the unfamiliar adult female on vocalizations and cortisol levels occurred despite behavioral interactions, such as heightened aggression and sexual behavior, not seen during tests with the mother. It is suggested that the unfamiliar adult female's effectiveness in reducing HPA activity during exposure to novelty may facilitate the change in patterns of social interaction occurring in recently weaned animals. Copyright 2000 John Wiley & Sons, Inc.

Social structure affects mating competition in a damselfish

Science.gov (United States)

Wacker, Sebastian; Ness, Miriam Horstad; Östlund-Nilsson, Sara; Amundsen, Trond

2017-12-01

The strength of mating competition and sexual selection varies over space and time in many animals. Such variation is typically driven by ecological and demographic factors, including adult sex ratio and consequent availability of mates. The spatial scale at which demographic factors affect mating competition and sexual selection may vary but is not often investigated. Here, we analyse variation in size and sex ratio of social groups, and how group structure affects mating competition, in the site-attached damselfish Chrysiptera cyanea. Site-attached reef fishes are known to show extensive intraspecific variation in social structure. Previous work has focused on species for which the size and dynamics of social groups are constrained by habitat, whereas species with group structure unconstrained by habitat have received little attention. Chrysiptera cyanea is such a species, with individuals occurring in spatial clusters that varied widely in size and sex ratio. Typically, only one male defended a nest in multi-male groups. Nest-holding males were frequently visited by mate-searching females, with more visits in groups with more females, suggesting that courtship and mating mostly occur within groups and that male mating success depends on the number of females in the group. Male-male aggression was frequent in multi-male groups but absent in single-male groups. These findings demonstrate that groups are distinct social units. In consequence, the dynamics of mating and reproduction are mainly a result of group structure, largely unaffected short term by overall population demography which would be important in open social systems. Future studies of the C. cyanea model system should analyse longer-term dynamics, including how groups are formed, how they vary in relation to density and time of season and how social structure affects sexual selection.

Age-dependent male mating investment in Drosophila pseudoobscura.

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Sumit Dhole

Full Text Available Male mating investment can strongly influence fitness gained from a mating. Yet, male mating investment often changes with age. Life history theory predicts that mating investment should increase with age, and males should become less discriminatory about their mate as they age. Understanding age-dependent changes in male behavior and their effects on fitness is important for understanding how selection acts in age-structured populations. Although the independent effects of male or female age have been studied in many species, how these interact to influence male mating investment and fitness is less well understood. We mated Drosophila pseudoobscura males of five different age classes (4-, 8-, 11-, 15-, 19-day old to either young (4-day or old (11-day females, and measured copulation duration and early post-mating fecundity. Along with their independent effects, we found a strong interaction between the effects of male and female ages on male mating investment and fitness from individual matings. Male mating investment increased with male age, but this increase was more prominent in matings with young females. Male D. pseudoobscura made smaller investments when mating with old females. The level of such discrimination based on female age, however, also changed with male age. Intermediate aged males were most discriminatory, while the youngest and the oldest males did not discriminate between females of different ages. We also found that larger male mating investments resulted in higher fitness payoffs. Our results show that male and female ages interact to form a complex pattern of age-specific male mating investment and fitness.

Postnatal nutrition influences male attractiveness and promotes plasticity in male mating preferences

Science.gov (United States)

Noguera, José C.; Metcalfe, Neil B.; Monaghan, Pat

2017-12-01

Poor early-life nutrition could reduce adult reproductive success by negatively affecting traits linked to sexual attractiveness such as song complexity. If so, this might favor strategic mate choice, allowing males with less complex songs to tailor their mating tactics to maximize the reproductive benefits. However, this possibility has been ignored in theoretical and empirical studies. By manipulating the micronutrient content of the diet (e.g., low or high) during the postnatal period of male zebra finches, we show for the first time (1) that males reared on a poor (low) micronutrient diet had less complex songs as adults; (2) that these males, in contrast to the high micronutrient diet group, were more selective in their mating strategies, discriminating against those females most likely to reduce their clutch size when paired with males having less complex songs; and (3) that by following different mating strategies, males reared on the contrasting diets obtained similar reproductive benefits. These results suggest that early-life dietary conditions can induce multiple and long-lasting effects on male and female reproductive traits. Moreover, the results seem to reflect a previously unreported case of adaptive plasticity in mate choice in response to a nutritionally mediated reduction in sexual attractiveness.

Ontogenetic shifts in male mating preference and morph-specific polyandry in a female colour polymorphic insect

NARCIS (Netherlands)

Sanchez-Guillen, Rosa Ana; Hammers, Martijn; Hansson, Bengt; Van Gossum, Hans; Cordero-Rivera, Adolfo; Galicia Mendoza, Dalia Ivette; Wellenreuther, Maren

2013-01-01

Background: Sexual conflict over mating rates may favour the origin and maintenance of phenotypes with contrasting reproductive strategies. The damselfly Ischnura elegans is characterised by a female colour polymorphism that consists of one androchrome and two gynochrome female morphs. Previous

A noninvasive method for in situ determination of mating success in female American lobsters (Homarus americanus).

Science.gov (United States)

Goldstein, Jason S; Pugh, Tracy L; Dubofsky, Elizabeth A; Lavalli, Kari L; Clancy, Michael; Watson, Winsor H

2014-02-07

Despite being one of the most productive fisheries in the Northwest Atlantic, much remains unknown about the natural reproductive dynamics of American lobsters. Recent work in exploited crustacean populations (crabs and lobsters) suggests that there are circumstances where mature females are unable to achieve their full reproductive potential due to sperm limitation. To examine this possibility in different regions of the American lobster fishery, a reliable and noninvasive method was developed for sampling large numbers of female lobsters at sea. This method involves inserting a blunt-tipped needle into the female's seminal receptacle to determine the presence or absence of a sperm plug and to withdraw a sample that can be examined for the presence of sperm. A series of control studies were conducted at the dock and in the laboratory to test the reliability of this technique. These efforts entailed sampling 294 female lobsters to confirm that the presence of a sperm plug was a reliable indicator of sperm within the receptacle and thus, mating. This paper details the methodology and the results obtained from a subset of the total females sampled. Of the 230 female lobsters sampled from George's Bank and Cape Ann, MA (size range = 71-145 mm in carapace length), 90.3% were positive for sperm. Potential explanations for the absence of sperm in some females include: immaturity (lack of physiological maturity), breakdown of the sperm plug after being used to fertilize a clutch of eggs, and lack of mating activity. The surveys indicate that this technique for examining the mating success of female lobsters is a reliable proxy that can be used in the field to document reproductive activity in natural populations.

Evasive mating behaviour by female nurse sharks, Ginglymostoma cirratum (Bonnaterre, 1788, in an equatorial insular breeding ground

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André S. Afonso

Full Text Available ABSTRACT Mating events and aggregations of vulnerable nurse sharks Ginglymostoma cirratum were recorded in the insular protected area of Fernando de Noronha (FEN, Brazil, between April and August 2015. Female sharks were observed clustering in groups of up to 14 individuals in shallow water adjacent to the shore. Several evasive mating behaviours in the presence of males were noticed, including shoreward movement, positioning ventral side up at the sea surface with emerged pectoral and pelvic fins, body rolling and caudal fin thrashing. Fresh bite marks indicative of male courtship and coupling attempts were visible in female's pectoral and caudal fins. Altogether, the observed behaviours match previous reports of non-cooperative female nurse sharks during mating opportunities. An extended mating season coupled with a persistent use of inshore habitats result in nurse sharks being particularly vulnerable to human pressure during a most sensitive stage of their life cycle. The effective conservation of nurse shark populations from the western South Atlantic may thus depend on the protection of critical habitats where this species aggregates to reproduce. Explicitly addressing environmental requirements by vulnerable species in local management strategies is indispensable to ensure that human pressure, including ecotourism development, does not collide with stipulated conservation aims.

Divorce in the barn owl: securing a compatible or better mate entails the cost of re-pairing with a less ornamented female mate.

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Dreiss, A N; Roulin, A

2014-06-01

Two nonmutually exclusive hypotheses can explain why divorce is an adaptive strategy to improve reproductive success. Under the 'better option hypothesis', only one of the two partners initiates divorce to secure a higher-quality partner and increases reproductive success after divorce. Under the 'incompatibility hypothesis', partners are incompatible and hence they may both increase reproductive success after divorce. In a long-term study of the barn owl (Tyto alba), we address the question of whether one or the two partners derive fitness benefits by divorcing. Our results support the hypothesis that divorce is adaptive: after a poor reproductive season, at least one of the two divorcees increase breeding success up to the level of faithful pairs. By breeding more often together, faithful pairs improve coordination and thereby gain in their efficiency to produce successful fledglings. Males would divorce to obtain a compatible mate rather than a mate of higher quality: a heritable melanin-based signal of female quality did not predict divorce (indicating that female absolute quality may not be the cause of divorce), but the new mate of divorced males was less melanic than their previous mate. This suggests that, at least for males, a cost of divorce may be to secure a lower-quality but compatible mate. The better option hypothesis could not be formally rejected, as only one of the two divorcing partners commonly succeeded in obtaining a higher reproductive success after divorce. In conclusion, incompatible partners divorce to restore reproductive success, and by breeding more often together, faithful partners improve coordination. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

A test of genetic association among male nuptial coloration, female mating preference, and male aggression bias within a polymorphic population of cichlid fish

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Inke van der SLUIJS, Peter D. DIJKSTRA, Charlotte M. LINDEYER et al.

2013-04-01

Full Text Available Both inter- and intrasexual selection have been implicated in the origin and maintenance of species-rich taxa with diverse sexual traits. Simultaneous disruptive selection by female mate choice and male-male competition can, in theory, lead to speciation without geographical isolation if both act on the same male trait. Female mate choice can generate discontinuities in gene flow, while male-male competition can generate negative frequency-dependent selection stabilizing the male trait polymorphism. Speciation may be facilitated when mating preference and/or aggression bias are physically linked to the trait they operate on. We tested for genetic associations among female mating preference, male aggression bias and male coloration in the Lake Victoria cichlid Pundamilia. We crossed females from a phenotypically variable population with males from both extreme ends of the phenotype distribution in the same population (blue or red. Male offspring of a red sire were significantly redder than males of a blue sire, indicating that intra-population variation in male coloration is heritable. We tested mating preferences of female offspring and aggression biases of male offspring using binary choice tests. There was no evidence for associations at the family level between female mating preferences and coloration of sires, but dam identity had a significant effect on female mate preference. Sons of the red sire directed significantly more aggression to red than blue males, whereas sons of the blue sire did not show any bias. There was a positive correlation among individuals between male aggression bias and body coloration, possibly due to pleiotropy or physical linkage, which could facilitate the maintenance of color polymorphism [Current Zoology 59 (2: 221-229, 2013].

An integrative mating system assessment of a nonmodel, economically important Pacific rockfish (Sebastes melanops) reveals nonterritorial polygamy and conservation implications for a large species flock

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Karageorge, Kurt W.; Wilson, Raymond R.

2017-01-01

Abstract Characterizing the mating systems of long‐lived, economically important Pacific rockfishes comprising the viviparous Sebastes species flock is crucial for their conservation. However, direct assignment of mating success to sires is precluded by open, offshore populations and high female fecundity. We addressed this challenge by integrating paternity‐assigned mating success of females with the adult sex ratio (ASR) of the population, male evolutionary responses to receptive females, a...

Mate-Choice Copying in Single and Coupled Women: The Influence of Mate Acceptance and Mate Rejection Decisions of other Women

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Yan Deng

2015-01-01

Full Text Available Studies of humans and non-human animals indicate that females tend to change the likelihood of choosing a potential mate based on the decisions of other females; this is known as mate-choice copying. In a sample of both single and coupled women, we examined the influence of other women's (model mate-choice decisions, including mate acceptance and mate rejection, on participants' attractiveness ratings of men (target and willingness of mate selection. We also examined whether different types of relationships between the target men and the model women affected mate-choice copying. We found that both the single and coupled women showed mate-choice copying, but their response patterns differed. The significant effects for single women were dependent on a decrease in attractiveness ratings when they perceived the models' mate rejection. However, the significant findings for coupled women relied on an increase in attractiveness ratings when they observed the models' mate acceptance. Furthermore, the relationship status between the target men and the model women affected the magnitude of mate-choice copying effects for the single women. Specifically, they showed less mate-choice copying when the targets and models were in a committed romantic relationship than when in a temporary relationship.

Sex-role reversal of a monogamous pipefish without higher potential reproductive rate in females.

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Sogabe, Atsushi; Yanagisawa, Yasunobu

2007-12-07

In monogamous animals, males are usually the predominant competitors for mates. However, a strictly monogamous pipefish Corythoichthys haematopterus exceptionally exhibits a reversed sex role. To understand why its sex role is reversed, we measured the adult sex ratio and the potential reproductive rate (PRR), two principal factors influencing the operational sex ratio (OSR), in a natural population of southern Japan. The adult sex ratio was biased towards females throughout the breeding season, but the PRR, which increased with water temperature, did not show sexual difference. We found that an alternative index of the OSR (Sf/Sm: sex ratio of 'time in') calculated from the monthly data was consistently biased towards females. The female-biased OSR associated with sex-role reversal has been reported in some polyandrous or promiscuous pipefish, but factors biasing the OSR differed between these pipefish and C. haematopterus. We concluded that the similar PRR between the sexes in C. haematopterus does not confer reproductive benefit of polygamous mating on either sex, resulting in strict monogamous mating, and its female-biased adult sex ratio promotes female-female competition for a mate, resulting in sex-role reversal.

Description of immatures and mating behavior of Liogenys bidenticeps Moser, 1919 (Coleoptera: Melolonthidae: Melolonthinae

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Sérgio Roberto Rodrigues

Full Text Available Abstract Description of immatures and mating behavior of Liogenys bidenticeps Moser, 1919 (Coleoptera: Melolonthidae: Melolonthinae. Some species of Melolonthinae are associated with several species of cropped plants, with larvae consuming roots and, in some cases, are considered as crop pests. In some agricultural regions of Brazil, larvae of L. bidenticeps are found associated with cultivated plants, and little information is available about this taxon. This study, aiming at expanding the knowledge about the morphology and behavior of this species, provides the description of immatures and mating behavior of adults. The studies were conducted at the experimental farm of the Universidade Estadual de Mato Grosso do Sul in Aquidauana, Mato Grosso do Sul state, Brazil, and the adults were collected with light trap and raised in the laboratory. Mating behavior was documented on video both in the field and under laboratory conditions. Descriptions and illustrations of the third instar larva and pupa are presented. Adults have crepuscular flight activity and their copulation lasts an average of 20.25 min, occurring from 19:00 to 22:00 h. On some occasions, females did not accept males for copulation, indicating an active selection of males by females. Field observations demonstrated that adults feed on Brazilian pepper leaves (Schinus terebinthifolius, Anacardiaceae and cashew flowers (Anacardium occidentale, Anacardiaceae, where male and female meet each other and copulation occurs.

Sexually selected females in the monogamous Western Australian seahorse.

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Kvarnemo, Charlotta; Moore, Glenn I; Jones, Adam G

2007-02-22

Studies of sexual selection in monogamous species have hitherto focused on sexual selection among males. Here, we provide empirical documentation that sexual selection can also act strongly on females in a natural population with a monogamous mating system. In our field-based genetic study of the monogamous Western Australian seahorse, Hippocampus subelongatus, sexual selection differentials and gradients show that females are under stronger sexual selection than males: mated females are larger than unmated ones, whereas mated and unmated males do not differ in size. In addition, the opportunity for sexual selection (variance in mating success divided by its mean squared) for females is almost three times that for males. These results, which seem to be generated by a combination of a male preference for larger females and a female-biased adult sex ratio, indicate that substantial sexual selection on females is a potentially important but under-appreciated evolutionary phenomenon in monogamous species.

Reproductive traits and number of matings in males and females of Cerambyx welensii (Coleoptera: Cerambycidae) an emergent pest of oaks.

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Torres-Vila, L M; Mendiola-Diaz, F J; Conejo-Rodríguez, Y; Sánchez-González, Á

2016-06-01

The longhorn beetle Cerambyx welensii is an emerging pest involved in oak decline episodes, whose damage is increasingly reported in dehesa open woodlands. Knowledge of the reproductive biology of C. welensii is a crucial goal due to its new pest status. In this study, we assess the reproductive traits of both sexes in the laboratory (25°C and 60% relative humidity ). In females, body length was 44.9 ± 0.9 mm (mean ± SE), fecundity 132 ± 12 eggs, fertility 70 ± 1 %, longevity 70 ± 3 days, preoviposition period 2 ± 0.2 days, oviposition period 44 ± 3 days and postoviposition period 19 ± 3 days. Fecundity was positively correlated with female size, longevity and oviposition period. Daily fecundity was 3.0 ± 0.2 eggs/day and showed a fluctuating synovigenic pattern with a slight decreasing trend over time. Egg length was 4.24 ± 0.01 mm and egg volume 8.14 ± 0.04 mm3. Egg size was correlated with female size but the relative size of eggs was larger in smaller females. Incubation time was 13.9 ± 0.1 days and hatching did not depend on egg size. Neonate size was positively correlated with egg length. Females were polyandrous (more than 20 lifetime matings) but multiple mating did not increase fecundity, fertility or longevity. In males, body length was 43.7 ± 0.6 mm and longevity 52 ± 3 days. Unlike with females, longevity was positively correlated with male size. Males were polygynous (up to 30 lifetime matings) but mating history did not affect male longevity. Rather to the contrary, long-lived males mated more times because they had more mating chances. Lastly, C. welensii reproductive traits were compared with those other Cerambycidae species and discussed from an adaptive perspective. Our data will be useful to improve management of C. welensii in order to prevent or mitigate its impact in dehesa woodlands and other oak forests.

Genetic analysis of female mating recognition between Drosophila ananassae and Drosophila pallidosa: application of interspecific mosaic genome lines.

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Sawamura, Kyoichi; Zhi, Hua; Setoguchi, Koji; Yamada, Hirokazu; Miyo, Takahiro; Matsuda, Muneo; Oguma, Yuzuru

2008-06-01

Drosophila ananassae and Drosophila pallidosa are closely related species that can produce viable and fertile hybrids of both sexes, although strong sexual isolation exists between the two species. Females are thought to discriminate conspecific from heterospecific males based on their courtship songs. The genetic basis of female discrimination behavior was analyzed using isogenic females from interspecific mosaic genome lines that carry homozygous recombinant chromosomes. Multiple regression analysis indicated a highly significant effect of the left arm of chromosome 2 (2L) on the willingness of females to mate with D. ananassae males. Not only 2L but also the left arm of chromosome X (XL) and the right arm of chromosome 3 (3R) had significant effects on the females' willingness to mate with D. pallidosa males. All regions with strong effects on mate choice have chromosome arrangements characterized by species-specific inversions. Heterospecific combinations of 2L and 3R have previously been suggested to cause postzygotic reproductive isolation. Thus, genes involved in premating as well as postmating isolation are located in or near chromosomal inversions. This conclusion is consistent with the recently proposed hypothesis that "speciation genes" accumulate at a higher rate in non-recombining genome regions when species divergence occurs in the presence of gene flow.

Effect of gamma radiation on reproduction and mating competitiveness in the spiny bollworm, Enrias Insulana, (BOISD). Vol. 4

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Sallam, N A; Mohamed, H F [Biological Applications Department, Nuclear Research Center, Atomic Energy Authority, Cairo (Egypt); El-Dessouki, S A; El-Saedy, A A [Plant Protection Department, Faculty of Agriculture, Al-Azhar University, Cairo (Egypt)

1996-03-01

Adult moths less than 24 hours of the spiny bell worm, E. Insulana were exposed to 100, 200, 300, 400, 500, and 600 Gy of gamma radiation. The irradiated adults were paired with the untreated opposite sex. Fecundity of females decreased, almost proportionally with the increase in dose. The effect on fecundity was more pronounced in the case of irradiated females being paired with normal males than when normal were mated to irradiated males. Egg hatch was also dose dependent, as it decreased gradually with the increase in the radiation dose applied to adult males or females. however, both irradiated males and females have almost the same sensitivity and respondency to gamma radiation as reduction in hatch ability was concerned. Adult males irradiated with sub sterilizing doses of 100 or 300 Gy were more competitive than males irradiated with sterilizing dose of 600 Gy against untreated males in mating with normal females. Increasing the ratio of irradiated males to normal males from 1:1 to 5:1 decreased the rate of egg viability. 3 tabs.

Effect of gamma radiation on reproduction and mating competitiveness in the spiny bollworm, Enrias Insulana, (BOISD). Vol. 4

International Nuclear Information System (INIS)

Sallam, N.A.; Mohamed, H.F.; El-Dessouki, S.A.; El-Saedy, A.A.

1996-01-01

Adult moths less than 24 hours of the spiny bell worm, E. Insulana were exposed to 100, 200, 300, 400, 500, and 600 Gy of gamma radiation. The irradiated adults were paired with the untreated opposite sex. Fecundity of females decreased, almost proportionally with the increase in dose. The effect on fecundity was more pronounced in the case of irradiated females being paired with normal males than when normal were mated to irradiated males. Egg hatch was also dose dependent, as it decreased gradually with the increase in the radiation dose applied to adult males or females. however, both irradiated males and females have almost the same sensitivity and respondency to gamma radiation as reduction in hatch ability was concerned. Adult males irradiated with sub sterilizing doses of 100 or 300 Gy were more competitive than males irradiated with sterilizing dose of 600 Gy against untreated males in mating with normal females. Increasing the ratio of irradiated males to normal males from 1:1 to 5:1 decreased the rate of egg viability. 3 tabs

Honey bee queens do not count mates to assess their mating success

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The mating system of honey bees (genus Apis) is extremely polyandrous, where reproductive females (queens) typically mate with 12 or more males (drones) during their mating flight(s). The evolutionary implications for hyperpolyandry have been subject to considerable debate and empirical testing beca...

Female mate choice and the potential for ornament evolution in túngara frogs Physalaemus pustulosus

OpenAIRE

Michael J. RYAN, Ximena E. BERNA, A. Stanley RAND

2010-01-01

The potential for ornament evolution in response to sexual selection rests on the interaction between the permissiveness or selectivity of female preferences and the constraints on male development of signaling related traits. We investigate the former by determining how latent female preferences either exaggerate the magnitude of current traits (i.e. elaborations) or favor novel traits (i.e. innovations). In túngara frogs, females prefer complex mating calls (whine-chucks) to simple calls (...

Visual exposure to obesity: Experimental effects on attraction toward overweight men and mate choice in females.

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Robinson, E; Christiansen, P

2015-09-01

Cultural differences in ideal body weight are well established, but less research has examined attraction toward potential mates of heavier body weights. We examined whether exposure to obesity increases physical attraction toward overweight men. In Studies 1 and 2, we examined the effect that exposure to obese vs healthy weight men had on female attraction toward an overweight man. Study 3 examined whether females who are regularly exposed to males of heavier body weights reported a greater attraction toward overweight men. Study 4 tested whether females in an online dating study were more likely to choose to date an overweight man, after having been exposed to obesity. Exposure to obesity altered visual perceptions of what normal and therefore healthy body weights were and this resulted in greater attraction toward an overweight man (Studies 1 and 2). Females regularly exposed to men of heavier body weight reported a greater attraction toward overweight men (Study 3). After exposure to obesity, females in an online dating study were more likely to choose to date an overweight man ahead of a healthy weight man (Study 4). Exposure to male obesity increases female attraction toward overweight men and may affect mate choice.

Effects of social information on life history and mating tactics of males in the orb-web spider Argiope bruennichi.

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Cory, Anna-Lena; Schneider, Jutta M

2018-01-01

Informed mating decisions are often based on social cues providing information about prospective mating opportunities. Social information early in life can trigger developmental modifications and influence later mating decisions. A high adaptive value of such adjustments is particularly obvious in systems where potential mating rates are extremely limited and have to be carried out in a short time window. Males of the sexually cannibalistic spider Argiope bruennichi can achieve maximally two copulations which they can use for one (monogyny) or two females (bigyny). The choice between these male mating tactics should rely on female availability that males might assess through volatile sex pheromones emitted by virgin females. We predict that in response to those female cues, males of A. bruennichi should mature earlier and at a smaller body size and favor a bigynous mating tactic in comparison with controls. We sampled spiders from two areas close to the Southern and Northern species range to account for differences in mate quality and seasonality. In a fully factorial design, half of the subadult males from both areas obtained silk cues of females, while the other half remained without female exposure. Adult males were subjected to no-choice mating tests and could either monopolize the female or leave her (bigyny). We found that Southern males matured later and at a larger size than Northern males. Regardless of their origin, males also shortened the subadult stage in response to female cues, which, however, had no effects on male body mass. Contrary to our prediction, the frequencies of mating tactics were unaffected by the treatment. We conclude that while social cues during late development elicit adaptive life history adjustments, they are less important for the adjustment of mating decisions. We suggest that male tactics mostly rely on local information at the time of mate search.

Neurogenetics of female reproductive behaviors in Drosophila melanogaster.

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Laturney, Meghan; Billeter, Jean-Christophe

2014-01-01

We follow an adult Drosophila melanogaster female through the major reproductive decisions she makes during her lifetime, including habitat selection, precopulatory mate choice, postcopulatory physiological changes, polyandry, and egg-laying site selection. In the process, we review the molecular and neuronal mechanisms allowing females to integrate signals from both environmental and social sources to produce those behavioral outputs. We pay attention to how an understanding of D. melanogaster female reproductive behaviors contributes to a wider understanding of evolutionary processes such as pre- and postcopulatory sexual selection as well as sexual conflict. Within each section, we attempt to connect the theories that pertain to the evolution of female reproductive behaviors with the molecular and neurobiological data that support these theories. We draw attention to the fact that the evolutionary and mechanistic basis of female reproductive behaviors, even in a species as extensively studied as D. melanogaster, remains poorly understood. Copyright © 2014 Elsevier Inc. All rights reserved.

A comparison of two methods to assess audience-induced changes in male mate choice

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Madlen ZIEGE; Carmen HENNIGE-SCHULZ; Frauke MUECKSCH; David BIERBACH; Ralph TIEDEMANN; Bruno STREIT; Martin PLATH

2012-01-01

Multidirectional communicative interactions in social networks can have a profound effect on mate choice behavior.Male Atlantic molly Poecilia mexicana exhibit weaker mating preferences when an audience male is presented.This could be a male strategy to reduce sperm competition risk:interacting more equally with different females may be advantageous because rivals might copy mate choice decisions.In line with this hypothesis,a previous study found males to show a strong audience effect when being observed while exercising mate choice,but not when the rival was presented only before the choice tests.Audience effects on mate choice decisions have been quantified in poeciliid fishes using association preference designs,but it remains unknown if patterns found from measuring association times translate into actual mating behavior.Thus,we createl five audience treatments simulating different forms of perceived sperm competition risk and determined focal males' mating preferences by scoring pre-mating (nipping) and mating behavior (gonopodial thrusting).Nipping did not reflect the pattern that was found when association preferences were measured,while a very similar pattern was uncovered in thrusting behavior.The strongest response was observed when the audience could eavesdrop on the focal male's behavior.A reduction in the strength of focal males' preferences was also seen after the rival male had an opportunity to mate with the focal male's preferred mate.In comparison,the reduction of mating preferences in response to an audience was greater when measuring association times than actual mating behavior.While measuring direct sexual interactions between the focal male and both stimulus females not only the male's motivational state is reflected but also females' behavior such as avoidance of male sexual harassment [Current Zoology 58 (1):84-94,2012].

A novel disease affecting the predatory mite Phytoseiulus persimilis (Acari, Phytoseiidae): 2. Disease transmission by adult females.

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Schütte, Conny; Poitevin, Olivier; Negash, Tesfaye; Dicke, Marcel

2006-01-01

Adult female Phytoseiulus persimilis Athias-Henriot (Acari, Phytoseiidae) of one of our laboratory populations (=NR-population), show the following set of symptoms: predators shrink several days after mating, cease egg production and die several days after shrinking, show a lower degree of attraction to herbivore-induced plant volatiles and a shorter choice time in olfactometer tests, have the tendency to leave a prey patch with ample food, may carry excretory crystals in the legs, may cease prey consumption, and have a lower excretion rate. We hypothesized earlier that this characteristic syndrome, called non-responding (=NR-) syndrome, is caused by a pathogen infecting P. persimilis. To further support this hypothesis we here study several transmission modes of the factor causing the NR-syndrome. In all tests we measured size, short-term fecundity, mortality, predator position, response to plant odors and crystal location, thus including 6 of the 9 symptoms known yet. No evidence was found for vertical transmission from parent to offspring. Eggs from symptomatic females of the NR-population mated by males of the NR-population gave rise to normal-sized, well performing predators, when they had been surface sterilized or transferred to a new leaf. However, such eggs gave rise to shrunken females (17%) when left on the leaf where they had been laid. In the latter case transmission via products deposited on the leaf by the mothers was possible. We therefore tested several modes of horizontal transmission by exposing females of a commercial population that never showed the NR-syndrome (=R1-population) to products related to the symptomatic NR-population. No evidence was found for transmission via food or via squashed adult females. However, symptoms were induced in adult females of the R1-population after a 3-day exposure to a live adult female of the NR-population (incubation period=3-7 days, fraction shrunken females=53%) and after a 1-day exposure to feces and

Negative Assortative Mating Based on Body Coloration in the Freshwater Platyfish (Poecillidae: Xiphophorus maculatus

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Tyler E. Frankel

2017-04-01

Full Text Available The ability of individuals within a population to survive and thrive is highly dependent upon the maintenance of genetic variation and phenotypic diversity, thereby ensuring adaptation to dynamic environments. A fundamental method of maintaining such variation is through a negative assortative mating strategy, in which individuals would be expected to reproductively select members of the opposite sex that exhibit dissimilar phenotypes. Employing three uniform body color morphs, red, yellow and blue, of the platyfish (Xiphophorus maculatus, this study was designed to investigate whether X. maculatus females would preferentially be attracted to males exhibiting an alternative color, thereby enabling an examination of the effect of male body coloration on mate choice by adult females. Mate choice was determined based on the initial preference of each female, as well as the amount of time females spent associating with each male. Initial preferences were analyzed using a binomial distribution test, and overall preference data using Wilcoxon signed rank tests. Red females initially selected for dissimilar colored males, and spent a significantly larger amount of time associating with blue and yellow males, as did yellow females with red and blue males. Blue females initially selected and spent a significantly larger amount of time associating with red males but, interestingly, showed no selective preference between blue and yellow males. In these experimental trials, the overall strong mate selection exhibited by female platyfish for males of dissimilar coloration is suggestive of a negative assortative mating strategy and provides evidence for the maintenance of color polymorphism in nature populations.

The relevance of age and nutritional status on the mating competitiveness of medfly males (Diptera: Teprhitidae

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Alzira Kelly Passos Roriz

2013-10-01

Full Text Available Results of previous investigations trying to ascertain which physiological factors are more important to the mating success of medfly males are controversial. In part, this controversy owes to the fact that each factor was evaluated by an independent study using different experimental designs and populations. In the present study we compare the roles of age and nutritional status (immature and adult phases on the mating competitiveness of Ceratitis capitata (Wiedemann, 1824 males. Three parameters were used to evaluate the male mating success: calling behavior (pheromone emission, lek participation and copulation (ability to be chosen by a female. Females gave preference to the males that were given a high protein diet in the larval phase. By contrast, females did not give preference to males that had been well-nourished in the adult phase only. The other parameters evaluated followed the same pattern: young males and males that had been fed a high protein diet during their immature phase had a greater participation in leks and called more often than older males and males that had been fed a diet poor in protein during their larval phase. Therefore, we conclude that the mating success of C. capitata males is determined both by age and nourishment during the immature stage.

A novel disease affecting the predatory mite Phytoseiulus persimilis (Acari, Phytoseiidae): 1. Symptoms in adult females.

Science.gov (United States)

Schütte, Conny; Kleijn, Prisca W; Dicke, Marcel

2006-01-01

Adult female Phytoseiulus persimilis Athias-Henriot (Acari, Phytoseiidae) of one of our laboratory populations showed a lower degree of attraction to herbivore-induced plant volatiles than other laboratory populations. We hypothesized earlier that this consistent change in foraging behavior is a symptom of a disease, as it is a contagious phenomenon. Here we describe more symptoms by comparing mated females of this population (non-responding (NR) population) with mated females of other populations that are strongly attracted to herbivore-induced plant volatiles (responding populations). The most apparent characteristic of the NR population was the presence of numerous dorso-ventrally flattened females (76% of all females). These females had a normal size after mating but shrank during adulthood. Independent of their age, shrunken females did not reproduce and died a few days after shrinking. In addition to these profound differences in short term performance, females from the NR-population showed behavioral changes, including a lower degree of attraction to herbivore-induced plant volatiles, a higher tendency to leave a prey-patch and a lower predation rate. Moreover, about half of the live females of the NR-population carried birefringent dumbbell-shaped crystals in the legs whereas live females of a responding population carried crystals only in the lumen of the Malpighian tubules and the rectum. The symptom 'crystals in the legs' was correlated with low reproduction. Energy dispersive X-ray diffraction of these crystals revealed that they contain calcium and phosphorus along with carbon and oxygen. Crystals with comparable elemental compositions and the same characteristic concentric layering are well known in insects, where they are thought to play a major role in detoxification of calcium and heavy metals, and in storage of phosphorus. The fraction of predators carrying a white spot in the distal part of the opisthosoma, due to accumulation of excretory

Mating choice of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae): influence of male ageing on mating success

International Nuclear Information System (INIS)

Silva Neto, Alberto M. da; Dias, Vanessa S.; Joachim-Bravo, Iara S.

2009-01-01

The objective of this study was to evaluate the effect of male ageing on male pheromone release and mating success of Ceratitis capitata (Wiedemann). The effects of male ageing on mating were evaluated on fi ve and 21 d-old males by assessing their mating success (males chosen by a female for copulation) and the amount of males releasing the sex pheromone. The mating success was evaluated by using several ratios of young to older males by increasing the number of older males:young males from 1:1 to 5:1. The mating success of the 1:1 ratio was also evaluated in fi eld cages. The evaluation of the mating success (in the 1:1 ratio) showed a clear preference of the females for young males. Sex pheromone emission was much more common on young than older males. Even in cases were older males were more abundant (ratios 2:1 and 3:1), females still chose the young males. However, females could not distinguish young from older males in ratios of 4:1 or 5:1. Our data indicate that the ageing of C. capitata males has a considerable negative effect on their reproductive success, especially if they are found in a proportion any lower than 3:1. (author)

Influence of mating disruption on the reproductive biology of the vine mealybug, Planococcus ficus (Hemiptera: Pseudococcidae), under field conditions.

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Cocco, Arturo; Muscas, Enrico; Mura, Alessandra; Iodice, Andrea; Savino, Francesco; Lentini, Andrea

2018-05-08

Although mating disruption is increasingly being used to control the worldwide grapevine pest vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), its mode of action remains unclear. A three-year field experiment was carried out to investigate the effects of mating disruption on the development and reproduction of the vine mealybug. The influence of mating disruption applied over consecutive years on the pest population density was also evaluated. The percentage of ovipositing females was significantly reduced in disrupted plots by 18.8-66.2%, depending on the year. The absence of ovipositing females in disrupted plots in the autumn of the second and third year indicates the effectiveness of mating disruption throughout the whole growing season. Mating disruption consistently prolonged the pre-oviposition period in all years by up to 12.5 days. Our findings provide new insights into the mechanisms underlying the pheromone-based control of the vine mealybug and indicate that the reduction of the pest population density is due to both a decrease and delay in female mating. In addition, the population density of vine mealybugs under mating disruption decreased over years, indicating that consecutive applications of this control strategy would significantly increase the effectiveness of controlling the vine mealybug by mating disruption. This article is protected by copyright. All rights reserved.

Female genitalia concealment promotes intimate male courtship in a water strider.

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Chang S Han

2009-06-01

Full Text Available Violent coercive mating initiation is typical for animals with sexual conflict over mating. In these species, the coevolutionary arms-race between female defenses against coercive mating and male counter-adaptations for increased mating success leads to coevolutionary chases of male and female traits that influence the mating. It has been controversial whether one of the sexes can evolve traits that allow them to "win" this arms race. Here, we use morphological analysis (traditional and scanning electron micrographs, laboratory experiments and comparative methods to show how females of a species characterized by typical coercive mating initiation appear to "win" a particular stage of the sexual conflict by evolving morphology to hide their genitalia from direct, forceful access by males. In an apparent response to the female morphological adaptation, males of this species added to their typically violent coercive mounting of the female new post-mounting, pre-copulatory courtship signals produced by tapping the water's surface with the mid-legs. These courtship signals are intimate in the sense that they are aimed at the female, on whom the male is already mounted. Females respond to the signals by exposing their hidden genitalia for copulatory intromission. Our results indicate that the apparent victory of coevolutionary arms race by one sex in terms of morphology may trigger evolution of a behavioral phenotype in the opposite sex.

Estrogens can disrupt amphibian mating behavior.

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Frauke Hoffmann

Full Text Available The main component of classical contraceptives, 17α-ethinylestradiol (EE2, has high estrogenic activity even at environmentally relevant concentrations. Although estrogenic endocrine disrupting compounds are assumed to contribute to the worldwide decline of amphibian populations by adverse effects on sexual differentiation, evidence for EE2 affecting amphibian mating behaviour is lacking. In this study, we demonstrate that EE2 exposure at five different concentrations (0.296 ng/L, 2.96 ng/L, 29.64 ng/L, 2.96 µg/L and 296.4 µg/L can disrupt the mating behavior of adult male Xenopus laevis. EE2 exposure at all concentrations lowered male sexual arousal, indicated by decreased proportions of advertisement calls and increased proportions of the call type rasping, which characterizes a sexually unaroused state of a male. Additionally, EE2 at all tested concentrations affected temporal and spectral parameters of the advertisement calls, respectively. The classical and highly sensitive biomarker vitellogenin, on the other hand, was only induced at concentrations equal or higher than 2.96 µg/L. If kept under control conditions after a 96 h EE2 exposure (2.96 µg/L, alterations of male advertisement calls vanish gradually within 6 weeks and result in a lower sexual attractiveness of EE2 exposed males toward females as demonstrated by female choice experiments. These findings indicate that exposure to environmentally relevant EE2 concentrations can directly disrupt male mate calling behavior of X. laevis and can indirectly affect the mating behavior of females. The results suggest the possibility that EE2 exposure could reduce the reproductive success of EE2 exposed animals and these effects might contribute to the global problem of amphibian decline.

Azadirachtin effects on mating success, gametic abnormalities and progeny survival in Drosophila melanogaster (Diptera).

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Oulhaci, Chemseddine M; Denis, Béatrice; Kilani-Morakchi, Samira; Sandoz, Jean-Christophe; Kaiser, Laure; Joly, Dominique; Aribi, Nadia

2018-01-01

Azadirachtin is a prominent natural pesticide and represents an alternative to conventional insecticides. It has been successfully used against insect pests. However, its effects on reproduction require further analysis. Here we investigated lethal and sublethal effects of azadirachtin, on treated adults in a model insect, Drosophila melanogaster (Meigen). Dose-mortality relationships as well as several parameters of reproduction (mating, spermatogenesis, oogenesis and fertility) were examined. Neem-Azal, a commercial formulation of azadirachtin, applied topically on newly emerged adults, increased mortality with a positive dose-dependent relationship. The LD 50 (0.63 μg) was determined 24 h after treatment using a non-linear regression. Adults surviving this dose had a mating success that was divided by 3 and a progeny production reduced by half when males were treated, and even more when females were treated. When combining probability of survival, of mating and reduced progeny, it appeared that LD 50 induced a 98% reduction in reproductive rates. Reduced progeny was partially explained by the effect of adult treatment on gametes number and abnormalities. The number of cysts and the apical nuclei positions within the cysts decreased by 29.7% and 20%, respectively, in males. In females, the number of oocytes per ovary and the volume of basal oocytes also decreased by 16.1% and 32.4%, respectively. Azadirachtin causes significant toxic effects in both sexes and decreases the fecundity and fertility of D. melanogaster. Females are more sensitive to azadirachtin. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

the effect of heterosexual contact on libido and mating dexterity in ...

African Journals Online (AJOL)

stages of sexual development on adult behaviour are avail- able. Consequently. the present experiment was executed to determine the effects of total isolation as well as that of heterosexual contact during the pre· -and post-puberal phase on libido, mating dexterity and the occurrence of homosexuality in Karakul rams.

How parasitoid females produce sexy sons: a causal link between oviposition preference, dietary lipids and mate choice in Nasonia.

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Blaul, Birgit; Ruther, Joachim

2011-11-07

Sexual selection theory predicts that phenotypic traits used to choose a mate should reflect honestly the quality of the sender and thus, are often costly. Physiological costs arise if a signal depends on limited nutritional resources. Hence, the nutritional condition of an organism should determine both its quality as a potential mate and its ability to advertise this quality to the choosing sex. In insects, the quality of the offspring's nutrition is often determined by the ovipositing female. A causal connection, however, between the oviposition decisions of the mother and the mating chances of her offspring has never been shown. Here, we demonstrate that females of the parasitic wasp Nasonia vitripennis prefer those hosts for oviposition that have been experimentally enriched in linoleic acid (LA). We show by (13)C-labelling that LA from the host diet is a precursor of the male sex pheromone. Consequently, males from LA-rich hosts produce and release higher amounts of the pheromone and attract more virgin females than males from LA-poor hosts. Finally, males from LA-rich hosts possess three times as many spermatozoa as those from LA-poor hosts. Hence, females making the right oviposition decisions may increase both the fertility and the sexual attractiveness of their sons.

Sexual selection is influenced by both developmental and adult environments.

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Gillespie, Stephanie R; Scarlett Tudor, M; Moore, Allen J; Miller, Christine W

2014-12-01

Sexual selection is often assumed to be strong and consistent, yet increasing research shows it can fluctuate over space and time. Few experimental studies have examined changes in sexual selection in response to natural environmental variation. Here, we use a difference in resource quality to test for the influence of past environmental conditions and current environmental conditions on male and female mate choice and resulting selection gradients for leaf-footed cactus bugs, Narnia femorata. We raised juveniles on natural high- and low-quality diets, cactus pads with and without ripe cactus fruits. New adults were again assigned a cactus pad with or without fruit, paired with a potential mate, and observed for mating behaviors. We found developmental and adult encounter environments affected mating decisions and the resulting patterns of sexual selection for both males and females. Males were not choosy in the low-quality encounter environment, cactus without fruit, but they avoided mating with small females in the high-quality encounter environment. Females were choosy in both encounter environments, avoiding mating with small males. However, they were the choosiest when they were in the low-quality encounter environment. Female mate choice was also context dependent by male developmental environment. Females were more likely to mate with males that had developed on cactus with fruit when they were currently in the cactus with fruit environment. This pattern disappeared when females were in the cactus without fruit environment. Altogether, these results experimentally demonstrate context-dependent mate choice by both males and females. Furthermore, we demonstrate that simple, seasonal changes in resources can lead to fluctuations in sexual selection. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

No discrimination against previous mates in a sexually cannibalistic spider

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Fromhage, Lutz; Schneider, Jutta M.

2005-09-01

In several animal species, females discriminate against previous mates in subsequent mating decisions, increasing the potential for multiple paternity. In spiders, female choice may take the form of selective sexual cannibalism, which has been shown to bias paternity in favor of particular males. If cannibalistic attacks function to restrict a male's paternity, females may have little interest to remate with males having survived such an attack. We therefore studied the possibility of female discrimination against previous mates in sexually cannibalistic Argiope bruennichi, where females almost always attack their mate at the onset of copulation. We compared mating latency and copulation duration of males having experienced a previous copulation either with the same or with a different female, but found no evidence for discrimination against previous mates. However, males copulated significantly shorter when inserting into a used, compared to a previously unused, genital pore of the female.

REINFORCEMENT OF STICKLEBACK MATE PREFERENCES: SYMPATRY BREEDS CONTEMPT.

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Rundle, Howard D; Schluter, Dolph

1998-02-01

Detailed studies of reproductive isolation and how it varies among populations can provide valuable insight into the mechanisms of speciation. Here we investigate how the strength of premating isolation varies between sympatric and allopatric populations of threespine sticklebacks to test a prediction of the hypothesis of reinforcement: that interspecific mate discrimination should be stronger in sympatry than in allopatry. In conducting such tests, it is important to control for ecological character displacement between sympatric species because ecological character divergence may strengthen prezygotic isolation as a by-product. We control for ecological character displacement by comparing mate preferences of females from a sympatric population (benthics) with mate preferences of females from two allopatric populations that most closely resemble the sympatric benthic females in ecology and morphology. No-choice mating trials indicate that sympatric benthic females mate less readily with heterospecific (limnetic) than conspecific (benthic) males, whereas two different populations of allopatric females resembling benthics show no such discrimination. These differences demonstrate reproductive character displacement of benthic female mate choice. Previous studies have established that hybridization between sympatric species occurred in the past in the wild and that hybrid offspring have lower fitness than either parental species, thus providing conditions under which natural selection would favor individuals that do not hybridize. Results are therefore consistent with the hypothesis that female mate preferences have evolved as a response to reduced hybrid fitness (reinforcement), although direct effects of sympatry or a biased extinction process could also produce the pattern. Males of the other sympatric species (limnetics) showed a preference for smaller females, in contrast to the inferred ancestral preference for larger females, suggesting reproductive character

Multiple matings among glossina and the sterile male technique

International Nuclear Information System (INIS)

Pinhao, R.C.

1980-01-01

The fact that multiple matings are a common phenomenon among glossina turns the sterile male technique into a competition not between adult insects but between two types of sperm, and the proportion of females inseminated with the one or the other is given by the binomial (p+q)sup(n), where p is the percentage of normal males, q the percentage of sterile males and n the average number of matings per female. However, multiple matings cannot damage the effectiveness of the technique unless two conditions are present either separately or simultaneously: precocious death of the spermatozoa and reduced inseminating potential among the sterile males. Study of the factors which can alter the inseminating potential is thus important for those who wish to use the sterile male technique. These factors are of three kinds: factors connected with quality, with quantity and with availability. The first are associated with the nature and intensity of the alterations brought about in the spermatozoa by the sterilizing agent, the second with possible variations in the amount of sperm reaching the spermotheca, the third with the behaviour of the sterile males in the nature - that is, the question whether sterilization has a favourable or unfavourable influence on their chances of mating with wild females. The author describes his observations of the quantity of sperm produced by Glossina morsitans submorsitans males from the colony reared at the Institute for Tropical Hygiene and Medicine in Lisbon, compares them with the observations of other authors and discusses their practical significance. Specific research is suggested. Advantages from assessing the behaviour of colonies not by female productivity but by male inseminating potential, and appropriate laboratory techniques

Effects of thiamine deficiency on food intake and body weight increment in adult female and growing rats.

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Bâ, Abdoulaye

2012-09-01

The present study compared the effects of thiamine (vitamin B1) deficiency (TD) on the patterns of food intake and body weight in adult female and neonatal Wistar rats. The adults weighed 250-270 g at the start and were fed for 60 days either with a synthetic TD diet (211 B1) or with the same synthetic diet+thiamine (210 B1). TD led to a marked reduction in food intake and the body weight set point, both recovering rapidly to their initial level in only 3 days after dietetic reversion. The effects of TD in developing rats were evaluated by subjecting pregnant rats to thiamine restriction during different time windows: prenatal (3 days before mating to parturition); perinatal (7 days after mating to the 10th postnatal day); and postnatal (from parturition to weaning). The effect of TD on the occurrence of low birth weight and ponderal growth retardation was examined from postnatal days 1 to 45. Only perinatal TD significantly decreased birth weight relative to untreated or pair-fed controls. Moreover, compared with the control treatments, ponderal growth retardation was not induced by prenatal TD, whereas induction of TD from perinatal into postnatal periods did cause ponderal growth retardation, with long-lasting effects persisting in adulthood. The results suggest a major physiological role of thiamine in the homeostasis of body weight programming, increment, and set point regulation in both offspring and adult female rats.

You can't always get what you want: size assortative mating by mutual mate choice as a resolution of sexual conflict

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Thünken Timo

2009-06-01

Full Text Available Abstract Background Assortative mating patterns for mate quality traits like body size are often observed in nature. However, the underlying mechanisms that cause assortative mating patterns are less well known. Sexual selection is one important explanation for assortment, suggesting that i one (usually the female or both sexes could show preferences for mates of similar size or ii mutual mate choice could resolve sexual conflict over quality traits into assortment. We tested these hypotheses experimentally in the socially monogamous cichlid fish Pelvicachromis taeniatus, in which mate choice is mutual. Results In mate choice experiments, both sexes preferred large mates irrespective of own body size suggesting mating preferences are not size-assortative. Especially males were highly selective for large females, probably because female body size signals direct fitness benefits. However, when potential mates were able to interact and assess each other mutually they showed size-assortative mating patterns, i.e. the likelihood to mate was higher in pairs with low size differences between mates. Conclusion Due to variation in body size, general preferences for large mating partners result in a sexual conflict: small, lower quality individuals who prefer themselves large partners are unacceptable for larger individuals. Relative size mismatches between mates translate into a lower likelihood to mate, suggesting that the threshold to accept mates depends on own body size. These results suggest that the underlying mechanism of assortment in P. taeniatus is mutual mate choice resolving the sexual conflict over mates, rather than preference for mates of similar size.

Transgenerational epigenetic effects of the endocrine disruptor vinclozolin on pregnancies and female adult onset disease.

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Nilsson, Eric E; Anway, Matthew D; Stanfield, Jacob; Skinner, Michael K

2008-05-01

Endocrine disruptor exposure during gonadal sex determination was previously found to induce male rat adult onset transgenerational disease (F1-F4 generation), and this was associated with an alteration in the epigenetic (i.e., DNA methylation) programming of the male germ line. The current study was designed to characterize the transgenerational disease phenotypes of the female adult offspring. Pregnant rats (F0 generation) were treated transiently with vinclozolin (i.e., fungicide with anti-androgenic activity) on embryonic (E) days E8-E14 of gestation. F1 control and vinclozolin generation offspring from different litters were mated to produce F2 offspring, and similarly F2 generation animals produced F3 generation offspring. Observations demonstrated that 9 out of 105 pregnant rats (8.6%) from the vinclozolin F1-F3 generations exhibited uterine hemorrhage and/or anemia late in pregnancy. None (0 out of 82) of the control F1-F3 generation females had similar pregnancy problems. Complete blood cell counts and serum chemistry profiles demonstrated that selected vinclozolin generation animals, but not controls, exhibited marked regenerative anemia in late pregnancy. Examination of kidney histology revealed moderate or severe glomerular abnormalities in 67% of the vinclozolin F2 and F3 generation adult females compared with 18% of the controls. Adult female vinclozolin generation animals also developed various types of tumors in 6.5% of the animals (11 out of 170), while 2% of control-line animals (3 out of 151) developed mammary tumors. Observations demonstrate that vinclozolin exposure during gonadal sex determination promotes a transgenerational increase in pregnancy abnormalities and female adult onset disease states.

Genetic evidence for patrilocal mating behavior among Neandertal groups

DEFF Research Database (Denmark)

Lalueza-Fox, Carles; Rosas, Antonio; Estalrrich, Almudena

2011-01-01

The remains of 12 Neandertal individuals have been found at the El Sidrón site (Asturias, Spain), consisting of six adults, three adolescents, two juveniles, and one infant. Archaeological, paleontological, and geological evidence indicates that these individuals represent all or part of a contem...... of the three adult females carried different mtDNA lineages. These findings provide evidence to indicate that Neandertal groups not only were small and characterized by low genetic diversity but also were likely to have practiced patrilocal mating behavior....

Sperm Production and Mating Ability Among F1 males of Heliothis Virescens (F.)

International Nuclear Information System (INIS)

Ibrahim, S.M.; Sallam, H.A.

2000-01-01

Adult males of Heliothis Virescens (F.) less than 12 h-old were irradiated with sub sterilizing doses of 50,100 or 125 Gy then crossed with untreated virgin females. The resulted F 1 males 1-and 4-day-old were dissected to determine the production of eupyrene sperm bundles and its accumulation in the duplex region. In another test, an experiment was conducted to determine the ability of F 1 males to mate and transfer sperm to untreated females. The data show that, eupyrene sperm bundles were not found in the duplex of newly emerged males immediately after emergence Number of eupyrene sperm bundles descended to duplex was significantly affected at 125 Gy during the first dark: light cycle of sperm descended. Accumulation of eupyrene sperm bundles of unmated F 1 males was significantly reduced at 100 and 125 Gy. It is apparent that the first mating is the most important, even in the control, and the rate of females that achieved successful mating with F 1 males after the first ejaculate was markedly reduced. This reduction was directly related to the dose level of irradiation. The proportion of mated females without and sperm, with apyrene sperms only or those with reduced amount of eupyrene sperms was generally increased as the dose applied to P 1 increased

Am I a 6 or a 10? Mate Value Among Young Adult Survivors of Childhood Cancer and Healthy Peers.

Science.gov (United States)

Lehmann, Vicky; Tuinman, Marrit A; Keim, Madelaine C; Hagedoorn, Mariët; Gerhardt, Cynthia A

2018-02-01

This study focused on self-perceived mate value of young adult survivors of childhood cancer relative to healthy peers. Qualitative studies indicate potential problems surrounding romantic relationships among survivors, but systematic studies are missing. One-hundred forty-nine childhood cancer survivors and 149 matched controls completed online questionnaires about their mate value, social comparison strategies (i.e., upward/downward identifying/contrasting strategies), and marital status. Survivors and controls were aged 20-40 (M = 27.8), 55% were female, and survivors had been treated for brain tumors (n = 52; 35%), leukemia (n = 42; 28%), lymphoma (n = 31; 21%), or other solid tumors (n = 24; 16%) at 5-33 years before study participation. Survivors and controls did not differ on overall mate value, but on individual characteristics: Survivors thought they had a better sense of humor (d = 0.36), were more loyal (d = 0.32), had higher social status (d = 0.26), and were more ambitious (d = 0.19), while also considering themselves less sexually adventurous (d = 0.31), less healthy (d = 0.26), having less desire to have children (d = 0.21), and a less attractive face (d = 0.20). Higher mate value was related to being partnered, more upward-identifying, less upward-contrasting, and less downward-identifying strategies. Moreover, less downward-identifying was associated with higher mate value in survivors, but not controls; whereas greater downward-contrasting was associated with higher mate value among controls only (R 2  = 30.8%). Survivors do not generally view themselves as less valuable (potential) romantic partners, but they evaluate different characteristics either more positively or more negatively. Social comparison strategies offer targetable points of interventions to intervene on negative self-evaluations, potentially enhancing well-being.

An Interaction of the Pre- and Post-Weaning Diets Rich in Omega-6 Polyunsaturated Fats Alters Plasma Lipids, Hepatic Gene Expression and Aortic Vascular Reactivity in Adult 057Bl/6 Mice

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Kanta Chechi

2010-01-01

Full Text Available Aim To investigate the effects of diets rich in n-6 polyunsaturated fats (PUFA fed during pre- and post-weaning time periods on the lipid metabolism and vascular reactivity in adult C57Bl/6 mice, in order to assess the impact of maternal nutrition and its interaction with the offspring diet on the metabolism of adult offspring. Methods Female C57Bl/6 mice were fed a high-fat diet enriched with n-6 PUFA (P or control diet (C for 2-weeks before, during mating, gestation and lactation, while their pups received either P or C for 8-weeks post-weaning. Results A significant interaction between the maternal and post-weaning diets was observed for the offspring body weight, food-, caloric-intake, plasma lipids, hepatic mRNA expression of lecithin cholesterol acyltransferase, aortic contractile and relaxation responses ( P < 0.05. Conclusion The overall metabolic and physiological outcome in the offspring is dependent upon the interaction between the pre- and post-weaning dietary environments.

Polygyny, mate-guarding, and posthumous fertilization as alternative male mating strategies.

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Zamudio, K R; Sinervo, B

2000-12-19

Alternative male mating strategies within populations are thought to be evolutionarily stable because different behaviors allow each male type to successfully gain access to females. Although alternative male strategies are widespread among animals, quantitative evidence for the success of discrete male strategies is available for only a few systems. We use nuclear microsatellites to estimate the paternity rates of three male lizard strategies previously modeled as a rock-paper-scissors game. Each strategy has strengths that allow it to outcompete one morph, and weaknesses that leave it vulnerable to the strategy of another. Blue-throated males mate-guard their females and avoid cuckoldry by yellow-throated "sneaker" males, but mate-guarding is ineffective against aggressive orange-throated neighbors. The ultradominant orange-throated males are highly polygynous and maintain large territories; they overpower blue-throated neighbors and cosire offspring with their females, but are often cuckolded by yellow-throated males. Finally, yellow-throated sneaker males sire offspring via secretive copulations and often share paternity of offspring within a female's clutch. Sneaker males sire more offspring posthumously, indicating that sperm competition may be an important component of their strategy.

A comparison of two methods to assess audience-induced changes in male mate choice

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Madlen ZIEGE, Carmen HENNIGE-SCHULZ, Frauke MUECKSCH,David BIERBACH, Ralph TIEDEMANN, Bruno STREIT, Martin PLATH

2012-02-01

Full Text Available Multidirectional communicative interactions in social networks can have a profound effect on mate choice behavior. Male Atlantic molly Poecilia mexicana exhibit weaker mating preferences when an audience male is presented. This could be a male strategy to reduce sperm competition risk: interacting more equally with different females may be advantageous because rivals might copy mate choice decisions. In line with this hypothesis, a previous study found males to show a strong audience effect when being observed while exercising mate choice, but not when the rival was presented only before the choice tests. Audience effects on mate choice decisions have been quantified in poeciliid fishes using association preference designs, but it remains unknown if patterns found from measuring association times translate into actual mating behavior. Thus, we created five audience treatments simulating different forms of perceived sperm competition risk and determined focal males’ mating preferences by scoring pre-mating (nipping and mating behavior (gonopodial thrusting. Nipping did not reflect the pattern that was found when association preferences were measured, while a very similar pattern was uncovered in thrusting behavior. The strongest response was observed when the audience could eavesdrop on the focal male’s behavior. A reduction in the strength of focal males’ preferences was also seen after the rival male had an opportunity to mate with the focal male’s preferred mate. In comparison, the reduction of mating preferences in response to an audience was greater when measuring association times than actual mating behavior. While measuring direct sexual interactions between the focal male and both stimulus females not only the male’s motivational state is reflected but also females’ behavior such as avoidance of male sexual harassment [Current Zoology 58 (1: 84–94, 2012].

Mate loss affects survival but not breeding in black brant geese

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Nicolai, Christopher A.; Sedinger, James S.; Ward, David H.; Boyd, W. Sean

2012-01-01

For birds maintaining long-term monogamous relationships, mate loss might be expected to reduce fitness, either through reduced survival or reduced future reproductive investment. We used harvest of male brant during regular sport hunting seasons as an experimental removal to examine effects of mate loss on fitness of female black brant (Branta bernicla nigricans; hereafter brant). We used the Barker model in program MARK to examine effects of mate loss on annual survival, reporting rate, and permanent emigration. Survival rates decreased from 0.847 ± 0.004 for females who did not lose their mates to 0.690 ± 0.072 for birds who lost mates. Seber ring reporting rate for females that lost their mates were 2 times higher than those that did not lose mates, 0.12 ± 0.086 and 0.06 ± 0.006, respectively, indicating that mate loss increased vulnerability to harvest and possibly other forms of predation. We found little support for effects of mate loss on fidelity to breeding site and consequently on breeding. Our results indicate substantial fitness costs to females associated with mate loss, but that females who survived and were able to form new pair bonds may have been higher quality than the average female in the population.

Influence of mating on ovarian follicle development in Triatoma infestans (Klug, 1834

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S. Asin

1992-09-01

Full Text Available This works examines the influence of mating on ovarian follicle development in Triatoma infestans. The observations were carried out on both virgin and mated females, wich were killed at various times after their emergence. There was no difference in the ovarian development of both experimental groups during the first gonadotrofic cycle. By the 7th day mated females as well as virgn females showed vitellogenic oocytes. The coriogenesis and ovulation process began on the 13th day after imaginal moulting. However we could observe that egg-laying was dependent on mating. Mated females laid eggs whereas virgin females did not lay eggs. However ovarian production was significantly greater in the mated females. It is suggested that in T. infestans mating stimulates egg-laying but it does not influence the oogenesis and ovulation process.

Mate choice screening in captive solitary carnivores

DEFF Research Database (Denmark)

Noer, Christina Lehmkuhl; Balsby, Thorsten Johannes Skovbjerg; Anistoroaei, Razvan

2017-01-01

Mate choice studies suggest that choosy females benefit from increased fecundity, litter size, and offspring survival. Thus, providing females with the opportunity to choose among potential mates, deemed genetically suitable based on studbook data, might improve breeding management in production ...

Stress responsiveness predicts individual variation in mate selectivity.

Science.gov (United States)

Vitousek, Maren N; Romero, L Michael

2013-06-15

Steroid hormones, including glucocorticoids, mediate a variety of behavioral and physiological processes. Circulating hormone concentrations vary substantially within populations, and although hormone titers predict reproductive success in several species, little is known about how individual variation in circulating hormone concentrations is linked with most reproductive behaviors in free-living organisms. Mate choice is an important and often costly component of reproduction that also varies substantially within populations. We examined whether energetically costly mate selection behavior in female Galápagos marine iguanas (Amblyrhynchus cristatus) was associated with individual variation in the concentrations of hormones previously shown to differ between reproductive and non-reproductive females during the breeding season (corticosterone and testosterone). Stress-induced corticosterone levels - which are suppressed in female marine iguanas during reproduction - were individually repeatable throughout the seven-week breeding period. Mate selectivity was strongly predicted by individual variation in stress-induced corticosterone: reproductive females that secreted less corticosterone in response to a standardized stressor assessed more displaying males. Neither baseline corticosterone nor testosterone predicted variation in mate selectivity. Scaled body mass was not significantly associated with mate selectivity, but females that began the breeding period in lower body condition showed a trend towards being less selective about potential mates. These results provide the first evidence that individual variation in the corticosterone stress response is associated with how selective females are in their choice of a mate, an important contributor to fitness in many species. Future research is needed to determine the functional basis of this association, and whether transient acute increases in circulating corticosterone directly mediate mate choice behaviors

Firefly Mating Algorithm for Continuous Optimization Problems

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Amarita Ritthipakdee

2017-01-01

Full Text Available This paper proposes a swarm intelligence algorithm, called firefly mating algorithm (FMA, for solving continuous optimization problems. FMA uses genetic algorithm as the core of the algorithm. The main feature of the algorithm is a novel mating pair selection method which is inspired by the following 2 mating behaviors of fireflies in nature: (i the mutual attraction between males and females causes them to mate and (ii fireflies of both sexes are of the multiple-mating type, mating with multiple opposite sex partners. A female continues mating until her spermatheca becomes full, and, in the same vein, a male can provide sperms for several females until his sperm reservoir is depleted. This new feature enhances the global convergence capability of the algorithm. The performance of FMA was tested with 20 benchmark functions (sixteen 30-dimensional functions and four 2-dimensional ones against FA, ALC-PSO, COA, MCPSO, LWGSODE, MPSODDS, DFOA, SHPSOS, LSA, MPDPGA, DE, and GABC algorithms. The experimental results showed that the success rates of our proposed algorithm with these functions were higher than those of other algorithms and the proposed algorithm also required fewer numbers of iterations to reach the global optima.

Personality may confound common measures of mate-choice.

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Morgan David

Full Text Available The measurement of female mating preferences is central to the study of the evolution of male ornaments. Although several different methods have been developed to assess sexual preference in some standardized way, the most commonly used procedure consists of recording female spatial association with different males presented simultaneously. Sexual preference is then inferred from time spent in front of each male. However, the extent to which the measurement of female mate-choice is related to exploration tendencies has not been addressed so far. In the present study we assessed the influence of variation in exploration tendencies, a trait closely associated to global personality, on the measurement of female mating preference in the zebra finch (Taeniopygia guttata using the widely used four-chamber choice-apparatus. The number of movements performed within both exploration and mate-choice apparatus was consistent within and across the two contexts. In addition, personality explained variation in selectivity, preference strength and consistency. High-exploratory females showed lower selectivity, lower preference scores and displayed more consistent preference scores. Our results suggest that variation in personality may affect the measurement of female mating preference and may contribute to explain existing inconsistencies across studies.

Mating competitiveness and the effect of X-rays and aging on males of Tetranychus urticae (Acarina, Tetranychidae) in relation to genetic control

International Nuclear Information System (INIS)

Feldmann, A.M.

1977-01-01

Males of Tetranychus urticae Koch were irradiated with X-ray doses of 4, 8, 24 and 32 krad (which were applied to 0-1 day-old adult virgin males) and tested in mating competition with one-day-old non-irradiated males. A non-significant excess of parental females were mated to the unirradiated males. This consistent trend in favour of females, mated with unirradiated males was highly significant, when the results of all the experiments were bulked. This indicated that radiation impaired the mating competitiveness of males of T. urticae. Aging of irradiated males resulted in a significant decrease of male-mating competitiveness at least within 2 days after irradiation. When 24 krad X-rays irradiated males were tested in mating competition at different ages, with unirradiated males of equal age, it was demonstrated that the reduction in mating competitiveness of aging irradiated males is caused by accelerated aging due to the irradiation treatment

Mate-sampling costs and sexy sons.

Science.gov (United States)

Kokko, H; Booksmythe, I; Jennions, M D

2015-01-01

Costly female mating preferences for purely Fisherian male traits (i.e. sexual ornaments that are genetically uncorrelated with inherent viability) are not expected to persist at equilibrium. The indirect benefit of producing 'sexy sons' (Fisher process) disappears: in some models, the male trait becomes fixed; in others, a range of male trait values persist, but a larger trait confers no net fitness advantage because it lowers survival. Insufficient indirect selection to counter the direct cost of producing fewer offspring means that preferences are lost. The only well-cited exception assumes biased mutation on male traits. The above findings generally assume constant direct selection against female preferences (i.e. fixed costs). We show that if mate-sampling costs are instead derived based on an explicit account of how females acquire mates, an initially costly mating preference can coevolve with a male trait so that both persist in the presence or absence of biased mutation. Our models predict that empirically detecting selection at equilibrium will be difficult, even if selection was responsible for the location of the current equilibrium. In general, it appears useful to integrate mate sampling theory with models of genetic consequences of mating preferences: being explicit about the process by which individuals select mates can alter equilibria. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Mating Competitiveness of Agrotis ipsilon (Hufn.) Irradiated as Parental Pupae

International Nuclear Information System (INIS)

El-Naggar, S.E.M.; Ibrahim, S.M.; El-Shall, S.S.A.

1999-01-01

Laboratory studied were carried out to evaluate the mating competitiveness of P 1 and F 1 generations of Agrotis ipsilon when irradiated as full grown pupae with 75 and 150 Gy of gamma irradiation. The mating competitiveness values showed that either males or females of P 1 or F 1 generation were full competitive after treatment with 75 or 150 Gy at all released ratios. Mating competitiveness of both irradiated males and females was also studied to avoid problems concerning mass sexing. The results revealed that confining both sexes together gave an excellent results for population suppression in both P 1 and F 1 in both tested doses and ratios. The addition of irradiated females to the release ratio make these females encountered in mating with untreated females, and possessed 78% of all matings occurred in parent generation in the two tested doses at 5:5:1 ratio and increased to reach 88% by F 1 females 75 Gy while it was reduced to only 31% at 150 Gy, but still act in mating

Mate call as reward: Acoustic communication signals can acquire positive reinforcing values during adulthood in female zebra finches (Taeniopygia guttata).

Science.gov (United States)

Hernandez, Alexandra M; Perez, Emilie C; Mulard, Hervé; Mathevon, Nicolas; Vignal, Clémentine

2016-02-01

Social stimuli can have rewarding properties and promote learning. In birds, conspecific vocalizations like song can act as a reinforcer, and specific song variants can acquire particular rewarding values during early life exposure. Here we ask if, during adulthood, an acoustic signal simpler and shorter than song can become a reward for a female songbird because of its particular social value. Using an operant choice apparatus, we showed that female zebra finches display a preferential response toward their mate's calls. This reinforcing value of mate's calls could be involved in the maintenance of the monogamous pair-bond of the zebra finch. (c) 2016 APA, all rights reserved).

Short-term exposure to a synthetic estrogen disrupts mating dynamics in a pipefish.

Science.gov (United States)

Partridge, Charlyn; Boettcher, Anne; Jones, Adam G

2010-11-01

Sexual selection is responsible for the evolution of some of the most elaborate traits occurring in nature, many of which play a vital role in competition over access to mates and individual reproductive fitness. Because expression of these traits is typically regulated by sex-steroids there is a significant potential for their expression to be affected by the presence of certain pollutants, such as endocrine disrupting compounds. Endocrine disruptors have been shown to alter primary sexual traits and impact reproduction, but few studies have investigated how these compounds affect secondary sexual trait expression and how that may, in turn, impact mating dynamics. In this study we examine how short-term exposure to a synthetic estrogen impacts secondary sexual trait expression and mating dynamics in the Gulf pipefish, a species displaying sex-role reversal. Our results show that only 10days of exposure to 17α-ethinylestradiol results in adult male pipefish developing female-like secondary sexual traits. While these males are capable of reproduction, females discriminate against exposed males in mate choice trials. In natural populations, this type of discrimination would reduce male mating opportunities, thus potentially reducing their long-term reproductive success. Importantly, the effects of these compounds on mating dynamics and mating opportunity would not be observed using the current standard methods of assessing environmental contamination. However, disrupting these processes could have profound effects on the viability of exposed populations. Copyright © 2010 Elsevier Inc. All rights reserved.

Nest-mate recognition in Manuelia postica (Apidae: Xylocopinae): an eusocial trait is present in a solitary bee.

Science.gov (United States)

Flores-Prado, Luis; Aguilera-Olivares, Daniel; Niemeyer, Hermann M

2008-02-07

In eusocial Hymenoptera, females are more tolerant towards nest-mate than towards non-nest-mate females. In solitary Hymenoptera, females are generally aggressive towards any conspecific female. Field observations of the nest biology of Manuelia postica suggested nest-mate recognition. Experiments were performed involving two live interacting females or one live female interacting with a dead female. Live females from different nests were more intolerant to each other than females from the same nest. Females were more intolerant towards non-nest-mate than towards nest-mate dead females. When dead females were washed with pentane, no differences in tolerant and intolerant behaviours were detected between non-nest-mate and nest-mate females. Females were more intolerant towards nest-mate female carcasses coated with the cuticular extract from a non-nest-mate than towards non-nest-mate female carcasses coated with the cuticular extract from a nest-mate. The compositions of the cuticular extracts was more similar between females from the same nest than between females from different nests. The results demonstrate for the first time nest-mate recognition mediated by cuticular chemicals in a largely solitary species of Apidae. The position of Manuelia at the base of the Apidae phylogeny suggests that nest-mate recognition in eusocial species apical to Manuelia represents the retention of a primitive capacity in Apidae.

Post-Mating Sexual Behaviors of Oriental Storks (Ciconia boyciana) in Captivity.

Science.gov (United States)

Yoon, Jongmin; Ha, Hae-Sook; Jung, Jung-Shim; Park, Shi-Ryong

2015-08-01

Parental behaviors that vary by sex and breeding stage facilitate the survival of offspring in birds. Females invest in reproducing according to the level of direct and/or indirect benefits provided by males. Males face trade-offs from defending territories or nests, providing for the young, and seeking additional mating opportunities. We examined whether post-mating sexual behaviors such as courtship display and nest-building were associated with reproductive investments made by males and females in the current study. The oriental stork (Ciconia boyciana) is known as a solitary breeder that nests in tall trees and provides biparental care with long post-hatching development. We filmed parental behaviors in seven stork pairs in captivity for 655 hours (245 hours during nest-building, 218 hours during incubation, 328 hours during nestling, and 192 hours during the fledgling period). We found that paired mating behaviors such as synchronous allopreening and bill-clattering were highly skewed to the pre-incubation period. Males participated in nest-building more than females although both sexes shared similar parental care during the incubation and nestling period. Male nest-building was negatively correlated with male nest attentiveness only during the nestling period. Our results suggest that male oriental storks with higher nest-building effort might spend more time taking precautions against conspecific intruders or nest predators near the nests with chicks while the females were attending the nests in the form of biparental care.

Mate choice in fruit flies is rational and adaptive.

Science.gov (United States)

Arbuthnott, Devin; Fedina, Tatyana Y; Pletcher, Scott D; Promislow, Daniel E L

2017-01-17

According to rational choice theory, beneficial preferences should lead individuals to sort available options into linear, transitive hierarchies, although the extent to which non-human animals behave rationally is unclear. Here we demonstrate that mate choice in the fruit fly Drosophila melanogaster results in the linear sorting of a set of diverse isogenic female lines, unambiguously demonstrating the hallmark of rational behaviour, transitivity. These rational choices are associated with direct benefits, enabling males to maximize offspring production. Furthermore, we demonstrate that female behaviours and cues act redundantly in mate detection and assessment, as rational mate choice largely persists when visual or chemical sensory modalities are impaired, but not when both are impaired. Transitivity in mate choice demonstrates that the quality of potential mates varies significantly among genotypes, and that males and females behave in such a way as to facilitate adaptive mate choice.

Disrupting Mating Behavior of Diaphorina citri (Liviidae).

Science.gov (United States)

Lujo, S; Hartman, E; Norton, K; Pregmon, E A; Rohde, B B; Mankin, R W

2016-12-01

Severe economic damage from citrus greening disease, caused by 'Candidatus Liberibacter asiaticus' bacteria, has stimulated development of methods to reduce mating and reproduction in populations of its insect vector, Diaphorina citri (Hemiptera: Liviidae). Male D. citri find mating partners by walking on host plants, intermittently producing vibrational calls that stimulate duetting replies by receptive females. The replies provide orientational feedback, assisting the search process. To test a hypothesis that D. citri mating can be disrupted using vibrational signals that compete with and/or mask female replies, courtship bioassays were conducted in citrus trees with or without interference from female reply mimics produced by a vibrating buzzer. Statistically significant reductions occurred in the rates and proportions of mating when the buzzer produced reply mimics within 0.4 s after male courtship calls compared with undisturbed controls. Observations of courtship behaviors in the two bioassays revealed activity patterns that likely contributed to the reductions. In both disruption and control tests, males reciprocated frequently between structural bifurcations and other transition points where signal amplitudes changed. Males in the disruption bioassay had to select among vibrational signals combined from the buzzer and the female at each transition point. They often turned towards the buzzer instead of the female. There was a statistically significant reduction in the proportion of males mating if they contacted the buzzer, possibly due to its higher vibration amplitude and duration in comparison with female replies. Potential applications of D. citri mating disruption technology in citrus groves are discussed. Published by Oxford University Press on behalf of Entomological Society of America 2016. This work is written by US Government employees and is in the public domain in the US.

Adult female acne: a new paradigm.

Science.gov (United States)

Dréno, B; Layton, A; Zouboulis, C C; López-Estebaranz, J L; Zalewska-Janowska, A; Bagatin, E; Zampeli, V A; Yutskovskaya, Y; Harper, J C

2013-09-01

In the adult female, acne is a chronic condition with a substantial negative psychological, social and emotional impact. Based on time of onset, two subtypes of adult female acne are recognized: 'persistent acne' is a continuation of the disease from adolescence, while 'late-onset acne' first presents in adulthood. The morphological characteristics of adult female acne are often distinct from adolescent acne. In adults, inflammatory lesions (particularly papules, pustules and nodules) are generally more prominent on the lower chin, jawline and neck, and comedones are more often closed comedones (micro cysts). Adult acne is mainly mild-to-moderate in severity and may be refractory to treatment. A holistic approach to acne therapy should be taken in adult females, which combines standard treatments with adjunctive therapy and cosmetic use. A number of factors specific to the adult female influence choice of treatment, including the predisposition of older skin to irritation, a possible slow response to treatment, a high likelihood of good adherence, whether of child-bearing age, and the psychosocial impact of the disease. Adherence to therapy should be encouraged through further patient education and a simplified regimen that is tailored to suit the individual patient's needs and lifestyle. This article reviews the specific characteristics of adult female acne, and provides recommendations for acne therapy in this patient group. © 2013 The Authors. Journal of the European Academy of Dermatology and Venereology © 2013 European Academy of Dermatology and Venereology.

Computational mate choice: theory and empirical evidence.

Science.gov (United States)

Castellano, Sergio; Cadeddu, Giorgia; Cermelli, Paolo

2012-06-01

The present review is based on the thesis that mate choice results from information-processing mechanisms governed by computational rules and that, to understand how females choose their mates, we should identify which are the sources of information and how they are used to make decisions. We describe mate choice as a three-step computational process and for each step we present theories and review empirical evidence. The first step is a perceptual process. It describes the acquisition of evidence, that is, how females use multiple cues and signals to assign an attractiveness value to prospective mates (the preference function hypothesis). The second step is a decisional process. It describes the construction of the decision variable (DV), which integrates evidence (private information by direct assessment), priors (public information), and value (perceived utility) of prospective mates into a quantity that is used by a decision rule (DR) to produce a choice. We make the assumption that females are optimal Bayesian decision makers and we derive a formal model of DV that can explain the effects of preference functions, mate copying, social context, and females' state and condition on the patterns of mate choice. The third step of mating decision is a deliberative process that depends on the DRs. We identify two main categories of DRs (absolute and comparative rules), and review the normative models of mate sampling tactics associated to them. We highlight the limits of the normative approach and present a class of computational models (sequential-sampling models) that are based on the assumption that DVs accumulate noisy evidence over time until a decision threshold is reached. These models force us to rethink the dichotomy between comparative and absolute decision rules, between discrimination and recognition, and even between rational and irrational choice. Since they have a robust biological basis, we think they may represent a useful theoretical tool for

Impact of male condition on his spermatophore and consequences for female reproductive performance in the Glanville fritillary butterfly.

Science.gov (United States)

Duplouy, Anne; Woestmann, Luisa; Gallego Zamorano, Juan; Saastamoinen, Marjo

2018-04-01

In butterflies, male reproductive success is highly related to the quality and the size of the spermatophore transferred to the female. The spermatophore is a capsule produced by the male during copulation, which in many species contains sperm in addition to a nuptial gift, and which is digested by the female after copulation. The nuptial gift may contribute to egg production and offspring quality, and in some cases also to female body maintenance. The production of the spermatophore, however, represents a cost for the male and, in polyandrous species, ejaculates are sometimes allocated adaptively across matings. Nonetheless, although the ecological factors affecting the reproductive success of female butterflies have been the topic of numerous studies, little information exists on the factors affecting males' contribution to reproduction, and the indirect impacts on female fecundity and fitness. We used the Glanville fritillary butterfly, Melitaea cinxia (Linnaeus, 1758) (Nymphalidae), in order to assess variation in male allocation to matings. In this species, smaller males produce smaller spermatophores, but variation in spermatophore size is not correlated with female reproductive success. We show that spermatophore size increases with male age at first mating, decreases with mating frequency and adult food-deprivation, and is not influenced by developmental food-limitation. The length of copulation period does not influence the spermatophore size nor influences the polyandrous mating behavior in this species. Male contribution to his spermatophore size is clearly influenced by his condition and adult-resource at the time of mating. Despite this variation, spermatophore size does not seem to have a direct impact on female reproductive output or mating behavior. © 2016 The Authors Insect Science published by Wiley Publishing Asia Pty Ltd on behalf of Institute of Zoology, Chinese Academy of Sciences.

Habitat change influences mate search behaviour in three-spined sticklebacks

DEFF Research Database (Denmark)

Heuschele, Jan; Salminen, Tiina; Candolin, Ulrika

2012-01-01

Mate choice is one of the main mechanisms of sexual selection, with profound implications for individual fitness. Changes in environmental conditions can cause individuals to alter their mate search behaviour, with consequences for mate choice. Human-induced eutrophication of water bodies...... is a global problem that alters habitat structure and visibility in aquatic ecosystems. We investigated whether changes in habitat complexity and male cue modality, visual or olfactory, influence mate search behaviour of female three-spined sticklebacks, Gasterosteus aculeatus. We allowed gravid females...... evaluation in the absence of visual stimulation. This reduced the rate of mate encounters and probably also the opportunity for choice. Our results show that changes in habitat structure and visibility can alter female mate searching, with potential consequences for the opportunity for sexual selection....

No detectable fertility benefit from a single additional mating in wild stalk-eyed flies.

Directory of Open Access Journals (Sweden)

Elisabeth Harley

2010-12-01

Full Text Available Multiple mating by female insects is widespread, and the explanation(s for repeated mating by females has been the subject of much discussion. Females may profit from mating multiply through direct material benefits that increase their own reproductive output, or indirect genetic benefits that increase offspring fitness. One particular direct benefit that has attracted significant attention is that of fertility assurance, as females often need to mate multiply to achieve high fertility. This hypothesis has never been tested in a wild insect population.Female Malaysian stalk-eyed flies (Teleopsis dalmanni mate repeatedly during their lifetime, and have been shown to be sperm limited under both laboratory and field conditions. Here we ask whether receiving an additional mating alleviates sperm limitation in wild females. In our experiment one group of females received a single additional mating, while a control group received an interrupted, and therefore unsuccessful, mating. Females that received an additional mating did not lay more fertilised eggs in total, nor did they lay proportionately more fertilised eggs. Female fertility declined significantly through time, demonstrating that females were sperm limited. However, receipt of an additional mating did not significantly alter the rate of this decline.Our data suggest that the fertility consequences of a single additional mating were small. We discuss this effect (or lack thereof, and suggest that it is likely to be attributed to small ejaculate size, a high proportion of failed copulations, and the presence of X-linked meiotic drive in this species.

Socio-sexual behavior of female northern muriquis (Brachyteles hypoxanthus).

Science.gov (United States)

Possamai, Carla B; Young, Robert J; Mendes, Sergio L; Strier, Karen B

2007-07-01

Female northern muriquis (Brachyteles hypoxanthus) are known to engage in frequent copulations with multiple partners, a pattern that in other primates has been attributed to various functions such as confusing paternity, reducing male aggression, or ensuring fertilization. However, in some female primates, promiscuity is restricted to times when conceptions are unlikely. We investigated whether female northern muriquis might exhibit a similarly mixed strategy by examining their mating, social, and activity patterns during their conception cycles versus other times. Systematic behavioral data were collected during an 18-month period between August 2001 and February 2003 on 13 adult females in a well-studied group at the RPPN-Feliciano Miguel Abdala, Minas Gerais, Brazil. Females mated on an average of 12.5+/-7.9 days during the study period, and spent significantly less time resting and engaging in non-sexual social behaviors, and significantly more time in sexual behaviors on days that they copulated than on days they did not. Three of the eight females for which sufficient data were available copulated significantly more often with their spatially closest non-kin associates, and four of five females that could be analyzed copulated significantly more often with their most frequent non-kin embrace partners. Comparisons between conception and non-conception periods revealed no differences in female activity budgets or in either the number of copulations or the number of different mating partners per female. Our results suggest that some females mate preferentially with close associates and social partners, but there is no indication that females alter their behavior during the cycles in which they conceive.

The Long and the Short of Mate Attraction in a Psylloid: do Semiochemicals Mediate Mating in Aacanthocnema dobsoni Froggatt?

Science.gov (United States)

Lubanga, Umar K; Drijfhout, Falko P; Farnier, Kevin; Steinbauer, Martin J

2016-02-01

Mating is preceded by a series of interdependent events that can be broadly categorized into searching and courtship. Long-range signals convey species- and sex-specific information during searching, while short-range signals provide information specific to individuals during courtship. Studies have shown that cuticular hydrocarbons (CHCs) can be used for mate recognition in addition to protecting insects from desiccation. In Psylloidea, four species rely on semiochemicals for long-range mate attraction. Psyllid mating research has focused on long-range mate attraction and has largely ignored the potential use of cuticular hydrocarbons (CHCs) as mate recognition cues. This study investigated whether CHCs of Aacanthocnema dobsoni have semiochemical activity for long- and short-range communication prior to mating. Using a solid sampler for solvent-less injection of whole psyllids into coupled gas chromatography/mass spectrometry, we found quantitative, sex- and age-related differences in CHC profiles. Males had higher proportions of 2-MeC28, 11,15-diMeC29, and n-C33 alkanes, while females had higher proportions of 5-MeC27, 3-MeC27, 5,15-diMeC27, n-C29 and n-C30 alkanes. In males and females, 84 and 68 % of CHCs varied with age, respectively. Y-tube olfactometer bioassays provided no evidence that males or females responded to odors emanating from groups of conspecifics of the opposite sex. Tests of male and female psyllids for attraction to branchlets previously occupied by conspecifics showed no evidence of attraction to possible semiochemical residues. Our short-range chemoreception bioassay showed that males were as indifferent to freshly killed individuals of either sex with intact CHC profiles as to those treated with hexane (to remove CHCs). Aacanthocnema dobsoni utilizes substrate-borne vibrations (SBVs) for communication. Therefore, our results indicate that SBVs are probably more important than semiochemicals for long-range mate attraction. Furthermore

Studies on mating competition of irradiated melon flies

International Nuclear Information System (INIS)

Limohpasmanee, W.

1994-01-01

Mating competition is the key factor for fruit flies control by using sterile insect technique project. Mass rearing and irradiation can reduce the mating competition of fruit flies. This experiment has purpose to evaluate the mating competition of the irradiated melon fly. The results show that mating competition values of irradiated melon flies were 0.36 and 0.24 when they mated with normal and irradiated females. Both normal male and female can mate more frequency than irradiated flies. (Z=1.322, P<0.05; Z=1.851, P<0.05). The results show that quality of mass rearing and irradiated melon fly was lower than the normal flies. So that quality of irradiated fly must be improved and the number of released flies as less must be higher than natural flies 6 time

Neurogenetics of female reproductive behaviors in Drosophila melanogaster

NARCIS (Netherlands)

Laturney, Meghan; Billeter, Jean-Christophe; Friedmann, T; Dunlap, JC; Goodwin, SF

2014-01-01

We follow an adult Drosophila melanogaster female through the major reproductive decisions she makes during her lifetime, including habitat selection, precopulatory mate choice, postcopulatory physiological changes, polyandry, and egg-laying site selection. In the process, we review the molecular

The evolution of sex roles in mate searching.

Science.gov (United States)

Fromhage, Lutz; Jennions, Michael; Kokko, Hanna

2016-03-01

Searching for mates is a critical stage in the life cycle of most internally, and many externally, fertilizing species. Males usually invest more in this costly activity than females, but the reasons for this are poorly understood. Previous models have shown that female-biased parental investment, including anisogamy, does not by itself select for male-biased mate searching, so it requires additional explanations. Here, we correct and expand upon earlier models, and present two novel hypotheses that might explain the evolution of male-biased mate searching. The "carry-over hypothesis" states that females benefit less from searching if the associated costs affect other stages of the life cycle, rather than arising only while searching. It is relevant to the evolution of morphological traits that improve searching efficiency but are also expressed in other contexts. The "mating window hypothesis" states that females benefit less from searching if their life cycle includes intervals during which the exact timing of mating does not matter for the appropriate timing of reproduction (e.g., due to sperm storage or delayed embryo implantation). Such intervals are more likely to exist for females given the general pattern of greater female parental investment. Our models shed new light on classic arguments about sex role evolution. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Parent-Offspring Conflict over Mating: The Case of Beauty

Directory of Open Access Journals (Sweden)

Menelaos Apostolou

2008-04-01

Full Text Available In pre-industrial societies parents exercise a strong influence over the mating decisions of their offspring. As modern pre-industrial societies approximate the way of life in ancestral human societies, human mating behavior should be seen as the outcome of a co-evolutionary process between parental and offspring's mating choice. Both parents and offspring have evolved mating preferences, which enable them to select those mates and in-laws who maximize their inclusive fitness. Following Trivers' (1974 theory of parent-offspring conflict, it is hypothesized that in-law and mating preferences substantially overlap, but also differ with respect to the beauty trait of a mating candidate. This hypothesis is tested on a sample of 292 parents. It is found that the two sets of preferences are strongly correlated, while beauty is preferred significantly more in a mating partner than in an in-law.

Receptive females mitigate costs of sexual conflict.

Science.gov (United States)

Harano, T

2015-02-01

Males typically gain fitness from multiple mating, whereas females often lose fitness from numerous mating, potentially leading to sexual conflict over mating. This conflict is expected to favour the evolution of female resistance to mating. However, females may incur male harassment if they refuse to copulate; thus, greater female resistance may increase costs imposed by males. Here, I show that the evolution of resistance to mating raises fitness disadvantages of interacting with males when mating is harmful in female adzuki bean beetles, Callosobruchus chinensis. Females that were artificially selected for higher and lower remating propensity evolved to accept and resist remating, respectively. Compared with females that evolved to accept remating, females that evolved to resist it suffered higher fitness costs from continuous exposure to males. The costs of a single mating measured by the effect on longevity did not differ among selection line females. This study indicates that receptive rather than resistant females mitigate the fitness loss resulting from sexual conflict, suggesting that even though mating is harmful, females can evolve to accept additional mating. © 2014 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Asymmetric dominance and asymmetric mate choice oppose premating isolation after allopatric divergence.

Science.gov (United States)

Sefc, Kristina M; Hermann, Caroline M; Steinwender, Bernd; Brindl, Hanna; Zimmermann, Holger; Mattersdorfer, Karin; Postl, Lisbeth; Makasa, Lawrence; Sturmbauer, Christian; Koblmüller, Stephan

2015-04-01

Assortative mating promotes reproductive isolation and allows allopatric speciation processes to continue in secondary contact. As mating patterns are determined by mate preferences and intrasexual competition, we investigated male-male competition and behavioral isolation in simulated secondary contact among allopatric populations. Three allopatric color morphs of the cichlid fish Tropheus were tested against each other. Dyadic male-male contests revealed dominance of red males over bluish and yellow-blotch males. Reproductive isolation in the presence of male-male competition was assessed from genetic parentage in experimental ponds and was highly asymmetric among pairs of color morphs. Red females mated only with red males, whereas the other females performed variable degrees of heteromorphic mating. Discrepancies between mating patterns in ponds and female preferences in a competition-free, two-way choice paradigm suggested that the dominance of red males interfered with positive assortative mating of females of the subordinate morphs and provoked asymmetric hybridization. Between the nonred morphs, a significant excess of negative assortative mating by yellow-blotch females with bluish males did not coincide with asymmetric dominance among males. Hence, both negative assortative mating preferences and interference of male-male competition with positive assortative preferences forestall premating isolation, the latter especially in environments unsupportive of competition-driven spatial segregation.

Mating behaviour in a slave-making ant, Rossomyrmex minuchae (Hymenoptera, Formicidae).

Science.gov (United States)

Ruano, Francisca; Tinaut, Alberto

2005-07-01

The mating behaviour of the ant Rossomyrmex minuchae, a rare, protected slave-making species in Spain, seems to be significantly affected by its particular life history and patchy habitat. The mating behaviour of the entire genus Rossomyrmex is virtually unknown. We present here the results of a 3-year study of mating behaviour in R. minuchae.Behavioural observations and limited nest excavations revealed that R. minuchae does not produce sexuals every year, the number of sexuals is low, and the sex ratio tends to be female biased. Females typically exhibit two distinct activity periods. The first, the mating period, takes place in early afternoon: the ants "call" near the natal nest, mate and then return to their nest. The second, the dispersal period takes place in late afternoon: the mated females exit their nest and fly in search of a new, non-parasitized Proformica longiseta host nest. Males are highly active during the mating period, but will remain inactive in the dispersal period even if experimentally presented with virgin females. It appears that females are monogamous, while males are polygamous. When males are late arriving at the female calling site, the females will frequently congregate presumably calling in chorus. The low reproductive efficiency exhibited by R. minuchae, coupled with the postulated low genetic variation in the population, as sisters may mate with the same male, could result in a low survival rate and risk of eventual extinction. The observed decrease in nest density we observed during the 2004 season may be indicative of such a process.

Sexual Experience Enhances Drosophila melanogaster Male Mating Behavior and Success

Science.gov (United States)

Saleem, Sehresh; Ruggles, Patrick H.; Abbott, Wiley K.; Carney, Ginger E.

2014-01-01

Competition for mates is a wide-spread phenomenon affecting individual reproductive success. The ability of animals to adjust their behaviors in response to changing social environment is important and well documented. Drosophila melanogaster males compete with one another for matings with females and modify their reproductive behaviors based on prior social interactions. However, it remains to be determined how male social experience that culminates in mating with a female impacts subsequent male reproductive behaviors and mating success. Here we show that sexual experience enhances future mating success. Previously mated D. melanogaster males adjust their courtship behaviors and out-compete sexually inexperienced males for copulations. Interestingly, courtship experience alone is not sufficient in providing this competitive advantage, indicating that copulation plays a role in reinforcing this social learning. We also show that females use their sense of hearing to preferentially mate with experienced males when given a choice. Our results demonstrate the ability of previously mated males to learn from their positive sexual experiences and adjust their behaviors to gain a mating advantage. These experienced-based changes in behavior reveal strategies that animals likely use to increase their fecundity in natural competitive environments. PMID:24805129

Sexual experience enhances Drosophila melanogaster male mating behavior and success.

Directory of Open Access Journals (Sweden)

Sehresh Saleem

Full Text Available Competition for mates is a wide-spread phenomenon affecting individual reproductive success. The ability of animals to adjust their behaviors in response to changing social environment is important and well documented. Drosophila melanogaster males compete with one another for matings with females and modify their reproductive behaviors based on prior social interactions. However, it remains to be determined how male social experience that culminates in mating with a female impacts subsequent male reproductive behaviors and mating success. Here we show that sexual experience enhances future mating success. Previously mated D. melanogaster males adjust their courtship behaviors and out-compete sexually inexperienced males for copulations. Interestingly, courtship experience alone is not sufficient in providing this competitive advantage, indicating that copulation plays a role in reinforcing this social learning. We also show that females use their sense of hearing to preferentially mate with experienced males when given a choice. Our results demonstrate the ability of previously mated males to learn from their positive sexual experiences and adjust their behaviors to gain a mating advantage. These experienced-based changes in behavior reveal strategies that animals likely use to increase their fecundity in natural competitive environments.

Temperature effects on the mating frequency of Anticarsia gemmatalis Huebner and Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae)

International Nuclear Information System (INIS)

Milano, Patricia; Berti Filho, Evoneo; Parra, Jose R.P.; Consoli, Fernando L.

2008-01-01

This paper deals with the influence of temperature on the mating frequency of two lepidopterans, Anticarsia gemmatalis Huebner and Spodoptera frugiperda (J.E. Smith), which use different strategies of allocation, and with the utilization of nutrients for their reproductive activities. The insects were reared on artificial diets at 25 deg C, and the adults were exposed to five temperatures (15, 20, 25, 30, and 35 deg C) to observe the influence of each temperature on their mating frequency, fecundity, fertility and longevity. The temperature affected the mating frequency of both species, being more evident at 15 deg C and 35 deg C, mainly for A. gemmatalis, which presented a drastic reduction on mating activities. The highest number of matings were observed from 20 deg C to 30 deg C, with S. frugiperda presenting mating activity (0-8) much higher than that of A. gemmatalis (0-2), but no correlation was observed among the number of matings and all other biological parameters evaluated (fecundity, fertility and longevity). However, S. frugiperda showed a positive correlation between fecundity and mating activity of females (r = 0.589; P = 0.003) at 25 deg C. The highest fecundities were observed at temperatures from 20 deg C to 30 deg C for S. frugiperda and at 25 deg C for A. gemmatalis. For both species, the longevity of males and females decreased as temperature increased. (author)

Male resource defense mating system in primates? An experimental test in wild capuchin monkeys.

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Barbara Tiddi

Full Text Available Ecological models of mating systems provide a theoretical framework to predict the effect of the defendability of both breeding resources and mating partners on mating patterns. In resource-based mating systems, male control over breeding resources is tightly linked to female mating preference. To date, few field studies have experimentally investigated the relationship between male resource control and female mating preference in mammals due to difficulties in manipulating ecological factors (e.g., food contestability. We tested the within-group male resource defense hypothesis experimentally in a wild population of black capuchin monkeys (Sapajus nigritus in Iguazú National Park, Argentina. Sapajus spp. represent an ideal study model as, in contrast to most primates, they have been previously argued to be characterized by female mate choice and a resource-based mating system in which within-group resource monopolization by high-ranking males drives female mating preference for those males. Here, we examined whether females (N = 12 showed a weaker preference for alpha males during mating seasons in which food distribution was experimentally manipulated to be less defendable relative to those in which it was highly defendable. Results did not support the within-group male resource defense hypothesis, as female sexual preferences for alpha males did not vary based on food defendability. We discuss possible reasons for our results, including the possibility of other direct and indirect benefits females receive in exercising mate choice, the potential lack of tolerance over food directed towards females by alpha males, and phylogenetic constraints.

The evolution of postpairing male mate choice.

Science.gov (United States)

Lyu, Nan; Servedio, Maria R; Lloyd, Huw; Sun, Yue-Hua

2017-06-01

An increasing number of empirical studies in animals have demonstrated male mate choice. However, little is known about the evolution of postpairing male choice, specifically which occurs by differential allocation of male parental care in response to female signals. We use a population genetic model to examine whether such postpairing male mate choice can evolve when males face a trade-off between parental care and extra-pair copulations (EPCs). Specifically, we assume that males allocate more effort to providing parental care when mated to preferred (signaling) females, but they are then unable to allocate additional effort to seek EPCs. We find that both male preference and female signaling can evolve in this situation, under certain conditions. First, this evolution requires a relatively large difference in parental investment between males mated to preferred versus nonpreferred females. Second, whether male choice and female signaling alleles become fixed in a population versus cycle in their frequencies depends on the additional fecundity benefits from EPCs that are gained by choosy males. Third, less costly female signals enable both signaling and choice alleles to evolve under more relaxed conditions. Our results also provide a new insight into the evolution of sexual conflict over parental care. © 2017 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Mate choice in the eye and ear of the beholder? Female multimodal sensory configuration influences her preferences.

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Ronald, Kelly L; Fernández-Juricic, Esteban; Lucas, Jeffrey R

2018-05-16

A common assumption in sexual selection studies is that receivers decode signal information similarly. However, receivers may vary in how they rank signallers if signal perception varies with an individual's sensory configuration. Furthermore, receivers may vary in their weighting of different elements of multimodal signals based on their sensory configuration. This could lead to complex levels of selection on signalling traits. We tested whether multimodal sensory configuration could affect preferences for multimodal signals. We used brown-headed cowbird ( Molothrus ater ) females to examine how auditory sensitivity and auditory filters, which influence auditory spectral and temporal resolution, affect song preferences, and how visual spatial resolution and visual temporal resolution, which influence resolution of a moving visual signal, affect visual display preferences. Our results show that multimodal sensory configuration significantly affects preferences for male displays: females with better auditory temporal resolution preferred songs that were shorter, with lower Wiener entropy, and higher frequency; and females with better visual temporal resolution preferred males with less intense visual displays. Our findings provide new insights into mate-choice decisions and receiver signal processing. Furthermore, our results challenge a long-standing assumption in animal communication which can affect how we address honest signalling, assortative mating and sensory drive. © 2018 The Author(s).

Negative-assortative mating for color in wolves.

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Hedrick, Philip W; Smith, Douglas W; Stahler, Daniel R

2016-04-01

There is strong negative-assortative mating for gray and black pelage color in the iconic wolves in Yellowstone National Park. This is the first documented case of significant negative-assortative mating in mammals and one of only a very few cases in vertebrates. Of 261 matings documented from 1995 to 2015, 63.6% were between gray and black wolves and the correlation between mates for color was -0.266. There was a similar excess of matings of both gray males × black females and black males × gray females. Using the observed frequency of negative-assortative mating in a model with both random and negative-assortative mating, the estimated proportion of negative-assortative mating was 0.430. The estimated frequency of black wolves in the population from 1996 to 2014 was 0.452 and these frequencies appear stable over this 19-year period. Using the estimated level of negative-assortative mating, the predicted equilibrium frequency of the dominant allele was 0.278, very close to the mean value of 0.253 observed. In addition, the patterns of genotype frequencies, that is, the observed proportion of black homozygotes and the observed excess of black heterozygotes, are consistent with negative-assortative mating. Importantly these results demonstrate that negative-assortative mating could be entirely responsible for the maintenance of this well-known color polymorphism. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

Decreased duration of pentobarbital-induced narcosis in immature and adult female rats prenatally exposed to cimetidine

International Nuclear Information System (INIS)

Donnelly, D.A.; Iba, M.M.

1986-01-01

The effect of prenatal cimetidine exposure (PreCM) on the duration of pentobarbital-induced narcosis (DPN) was assessed in immature (14- and 28-day old) and adult (50-60-day old) male and female rats. PreCM exposure was accomplished by treating mothers with cimetidine (CM) (20 mg/kg, ip) daily for the last two days of gestation and then (0.01% in drinking water) throughout lactation. Pregnant mothers of untreated offspring (Con) received saline. PreCM decreased DPN to 505 +/- 33 min (from 611 +/- 23 min in Con) and 393 +/- 190 min (from 686 +/- 44 min in Con) in 14-day old male and female rats, respectively. Similarly, PreCM decreased DPN to 88 +/- 15 min (from 134 +/- 3 min in Con) and 102 +/- 19 min (from 171 +/- 44 min in Con) in 28-day old male and female rats, respectively. At 21 days, PreCM did not alter DPN in either sex. At 50-60 days, however, it decreased DPN to 144 +/- 41 min (from 238 +/- 7 min in Con) in females but had no effect in males; PreCM also increased the plasma clearance of administered 14 C-pentobarbital more in females than in males. The effects of PreCM, particularly the long-term effects, were most prominent in female rats and were the opposite of those of postnatal treatment with CM. The results together with those of studies with hepatic microsomes suggest that PreCM may have resulted in the induction of hepatic drug-metabolizing enzymes during the perinatal period

Sex differences in adults' relative visual interest in female and male faces, toys, and play styles.

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Alexander, Gerianne M; Charles, Nora

2009-06-01

An individual's reproductive potential appears to influence response to attractive faces of the opposite sex. Otherwise, relatively little is known about the characteristics of the adult observer that may influence his or her affective evaluation of male and female faces. An untested hypothesis (based on the proposed role of attractive faces in mate selection) is that most women would show greater interest in male faces whereas most men would show greater interest in female faces. Further, evidence from individuals with preferences for same-sex sexual partners suggests that response to attractive male and female faces may be influenced by gender-linked play preferences. To test these hypotheses, visual attention directed to sex-linked stimuli (faces, toys, play styles) was measured in 39 men and 44 women using eye tracking technology. Consistent with our predictions, men directed greater visual attention to all male-typical stimuli and visual attention to male and female faces was associated with visual attention to gender conforming or nonconforming stimuli in a manner consistent with previous research on sexual orientation. In contrast, women showed a visual preference for female-typical toys, but no visual preference for male faces or female-typical play styles. These findings indicate that sex differences in visual processing extend beyond stimuli associated with adult sexual behavior. We speculate that sex differences in visual processing are a component of the expression of gender phenotypes across the lifespan that may reflect sex differences in the motivational properties of gender-linked stimuli.

Azadirachtin on Oligonychus yothersi in yerba mate Ilex paraguariensis

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Luis Francisco Angeli Alves

Full Text Available ABSTRACT: The red mite Oligonychus yothersi is one of the main pests of yerba mate in Brazil The damage this mite causes leads to leaf drop and decreased production. There are no registered acaricides for use in yerba mate; thus, laboratory and field experiments were performed to evaluate the effect of azadirachtin (Azamax(r, 250mL 100L-1 for the control of the red mite in yerba mate. In the laboratory, azadirachtin was applied to yerba mate leaf disks before (residual contact and after (direct contact infestation with 15 newly emerged red mite adult females. The effect of azadirachtin on mite behavior was evaluated in arenas with treated and untreated yerba mate leaves, and the number of mites in both areas was recorded. Ovicidal action was evaluated by applying azadirachtin to eggs and recording egg hatching. In the field, two applications of the product were performed (1L spray liquid plant-1 with a 7-day interval. The numbers of living mites were evaluated at 7, 14 and 21 days following the first application on randomly collected leaves. It was observed 86.6 and 91.4% of mortality following 24h of residual and direct contact, respectively. Repellent (62% of individuals leaving the treated area and ovicidal (98.9% decrease in egg hatching effects were also observed. The mite population in the yerba mate crop field had decreased by 59.6% at 14 days after the first application of azadirachtin. The results show the potential of azadirachtin for the control of O. yothersi in yerba mate in Brazil.

Early transfer of mated females into the maternity unit reduces stress and increases maternal care in farm mink

DEFF Research Database (Denmark)

Malmkvist, Jens; Palme, Rupert

2015-01-01

Mated mammals on farms are typically transferred to another housing environment prior to delivery. We investigated whether the timing of this transfer – EARLY (Day −36), INTERMEDIATE (Day −18), or LATE (Day −3) relative to the expected day of birth (Day 0) – affects maternal stress, maternal care...... sized groups (n = 60): (i) ‘EARLY’, transfer to maternity unit immediately after the end of the mating period, March 23; (ii) ‘INTERMEDIATE’, transfer in the middle of the period, April 10; (iii) ‘LATE’, transfer late in the pregnancy period, April 25. Data collection included weekly determination...... of faecal cortisol metabolites (FCM) and evaluation of maternal care: nest building, in-nest temperature, plus kit-retrieval behaviour, kit mortality and growth day 0–7 postpartum. We document that mated mink females build and maintain a nest at least 1 month prior to delivery when transferred...

Mate-choice copying, social information processing, and the roles of oxytocin.

Science.gov (United States)

Kavaliers, Martin; Matta, Richard; Choleris, Elena

2017-01-01

Social and sexual behaviors, including that of mate choice, are dependent on social information. Mate choice can be modified by prior and ongoing social factors and experience. The mate choice decisions of one individual can be influenced by either the actual or potential mate choice of another female or male. Such non-independent mate choice, where individuals gain social information and socially learn about and recognizes potential mates by observing the choices of another female or male, has been termed "mate-choice copying". Here we first briefly review how, why, and under what circumstances individuals engage in mate-choice copying. Secondly, we review the neurobiological mechanisms underlying mate-choice copying. In particular, we consider the roles of the nonapeptide, oxytocin, in the processing of social information and the expression of mate-choice copying. Copyright © 2016 Elsevier Ltd. All rights reserved.

Self-Perceived Mate Value, Facial Attractiveness, and Mate Preferences: Do Desirable Men Want It All?

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Arnocky, Steven

2018-01-01

Ten years ago, Buss and Shackelford demonstrated that high mate value (i.e., physically attractive) women held more discerning mate preferences relative to lower mate value women. Since then, researchers have begun to consider the equally important role of men's sexual selectivity in human mate choice. Yet, little research has focused on whether high mate value men are similarly choosy in their mate preferences. In a sample of 139 undergraduate men, relationships between self-perceived mate value as well as female-rated facial attractiveness were examined in relation to men's expressed mate preferences. Results showed that self-perceived mate value was unrelated to men's facial attractiveness as rated by women. Men who believed they were of high mate value were more likely than lower mate value men to prefer to marry at a younger age; to have a spouse who was younger than them; and to have a partner who was sociable, ambitious, high in social status, with good financial prospects, a desire for children, health, good looks, and mutual attraction. Objective male facial attractiveness was generally unrelated to heightened mate preferences, with the exception of heightened preference for similar religious background and good physical health. Findings suggest that men who perceive themselves as high in overall mate value are selective in their mate choice in a manner similar to high mate value women.

Sex specific molecular responses of quick-to-court protein in Indian malarial vector Anopheles culicifacies: conflict of mating versus blood feeding behaviour

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Tanwee Das De

2017-07-01

Full Text Available Understanding the molecular basis of mosquito behavioural complexity plays a central role in designing novel molecular tools to fight against their vector-borne diseases. Although the olfactory system plays an important role in guiding and managing many behavioural responses including feeding and mating, but the sex-specific regulation of olfactory responses remain poorly investigated. From our ongoing transcriptomic data annotation of olfactory tissue of blood fed adult female An. culicifacies mosquitoes; we have identified a 383 bp long unique transcript encoding a Drosophila homolog of the quick-to-court protein. Previously this was shown to regulate courtship behaviour in adult male Drosophila. A comprehensive in silico analysis of the quick-to-court (qtc gene of An. culicifacies (Ac-qtc predicts a 1536 bp single copy gene encoding 511 amino acid protein, having a high degree of conservation with other insect homologs. The age-dependent increased expression of putative Ac-qtc correlated with the maturation of the olfactory system, necessary to meet the sex-specific conflicting demand of mating (mate finding versus host-seeking behavioural responses. Sixteen to eighteen hours of starvation did not alter Ac-qtc expression in both sexes, however, blood feeding significantly modulated its response in the adult female mosquitoes, confirming that it may not be involved in sugar feeding associated behavioural regulation. Finally, a dual behavioural and molecular assay indicated that natural dysregulation of Ac-qtc in the late evening might promote the mating events for successful insemination. We hypothesize that Ac-qtc may play a unique role to regulate the sex-specific conflicting demand of mosquito courtship behaviour versus blood feeding behaviour in the adult female mosquitoes. Further elucidation of this molecular mechanism may provide further information to evaluate Ac-qtc as a key molecular target for mosquito-borne disease management.

Resolving the conflict of mating versus blood feeding: exploring role of quick-to-court gene in the mosquito Anopheles culicifacies

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Tanwee Das De

2017-10-01

Full Text Available Mosquitoes are the deadliest animal in the world. Mosquitoes transmit several vector borne disease (VBDs such as malaria, dengue, chikungunya, zika fever, yellow fever and responsible for a loss of millions of lives annually. Though, suppression of mosquito population by means of chemical insecticides plays a crucial role in controlling vector population. However, fast emergence of insecticide resistance limits the efforts and demanding to design alternative molecular tools to fight against these VBDs. One of the potential strategies may include interfering complex feeding and/or mating behavioural properties. Compared to female mosquito male mosquito have an indirect effect in disease transmission and thus least studied. Males induce several post-mating behavioural changes in females, including the induction of host seeking and blood feeding behavior. Although, a successful mating events are guided by non-genetic circadian rhythm, but how genetic factors manages the sequential events of swarm formation, suitable mate finding and aerial coupling remains poorly investigated. While understanding the complex feeding behaviour of adult An. culicifacies female mosquito, we identified and analyzed a unique transcript (383 bp from the olfactory system of the blood-fed mosquito, encoding the ‘quick to court’ (QTC protein. It is a homolog of Drosophila coiled-coil QTC (Q9VMU5 protein and shown to play an important role in driving the male courtship behaviour. A comprehensive in silico analysis predicted a 1536 bp long transcript encoding 511 AA long protein in the mosquito genome. Age dependent and sex specific transcriptional profiling revealed that both male female mosquitoes attain the specific age of adulteration on 5-7 days. Circadian clock dependent Ac-qtc profiling indicated that late evening natural dysregulation of Ac-qtc by unknown mechanism may promote the successful insemination event during active copulation. Together, our findings

Sport participation influences perceptions of mate characteristics.

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Schulte-Hostedde, Albrecht I; Eys, Mark A; Emond, Michael; Buzdon, Michael

2012-02-22

Sport provides a context in which mate choice can be facilitated by the display of athletic prowess. Previous work has shown that, for females, team sport athletes are more desirable as mates than individual sport athletes and non-participants. In the present study, the perceptions of males and females were examined regarding potential mates based on sport participation. It was predicted that team sport athletes would be more positively perceived than individual sport athletes and non-participants by both males and females. A questionnaire, a photograph, and manipulated descriptions were used to gauge perceptual differences with respect to team sport athletes, individual sport athletes, and extra-curricular club participants for 125 females and 119 males from a Canadian university. Both team and individual sport athletes were perceived as being less lazy, more competitive, and healthier than non-participants by both males and females. Interestingly, females perceived male athletes as more promiscuous than non-athletes, which upholds predictions based on previous research indicating (a) athletes have more sexual partners than non-athletes, and (b) females find athletes more desirable as partners than non-participants. Surprisingly, only males perceived female team sport athletes as more dependable than non-participants, and both team and individual sport athletes as more ambitious. This raises questions regarding the initial hypothesis that male team athletes would be perceived positively by females because of qualities such as the ability to cooperate, likeability, and the acceptance of responsibilities necessary for group functioning. Future studies should examine similar questions with a larger sample size that encompasses multiple contexts, taking into account the role of the social profile of sport in relation to mate choice and perception.

Infectious speciation revisited: impact of symbiont-depletion on female fitness and mating behavior of Drosophila paulistorum.

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Wolfgang J Miller

2010-12-01

Full Text Available The neotropical Drosophila paulistorum superspecies, consisting of at least six geographically overlapping but reproductively isolated semispecies, has been the object of extensive research since at least 1955, when it was initially trapped mid-evolution in flagrant statu nascendi. In this classic system females express strong premating isolation patterns against mates belonging to any other semispecies, and yet uncharacterized microbial reproductive tract symbionts were described triggering hybrid inviability and male sterility. Based on theoretical models and limited experimental data, prime candidates fostering symbiont-driven speciation in arthropods are intracellular bacteria belonging to the genus Wolbachia. They are maternally inherited symbionts of many arthropods capable of manipulating host reproductive biology for their own benefits. However, it is an ongoing debate as to whether or not reproductive symbionts are capable of driving host speciation in nature and if so, to what extent. Here we have reevaluated this classic case of infectious speciation by means of present day molecular approaches and artificial symbiont depletion experiments. We have isolated the α-proteobacteria Wolbachia as the maternally transmitted core endosymbionts of all D. paulistorum semispecies that have coevolved towards obligate mutualism with their respective native hosts. In hybrids, however, these mutualists transform into pathogens by overreplication causing embryonic inviability and male sterility. We show that experimental reduction in native Wolbachia titer causes alterations in sex ratio, fecundity, and mate discrimination. Our results indicate that formerly designated Mycoplasma-like organisms are most likely Wolbachia that have evolved by becoming essential mutualistic symbionts in their respective natural hosts; they have the potential to trigger pre- and postmating isolation. Furthermore, in light of our new findings, we revisit the concept of

Role of amygdala kisspeptin in pubertal timing in female rats.

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Daniel A Adekunbi

Full Text Available To investigate the mechanism by which maternal obesity disrupts reproductive function in offspring, we examined Kiss1 expression in the hypothalamic arcuate (ARC and anteroventral periventricular (AVPV nuclei, and posterodorsal medial amygdala (MePD of pre-pubertal and young adult offspring. Sprague-Dawley rats were fed either a standard or energy-dense diet for six weeks prior to mating and throughout pregnancy and lactation. Male and female offspring were weaned onto normal diet on postnatal day (pnd 21. Brains were collected on pnd 30 or 100 for qRT-PCR to determine Kiss1 mRNA levels. Maternal obesity increased Kiss1 mRNA expression in the MePD of pre-pubertal male and female offspring, whereas Kiss1 expression was not affected in the ARC or AVPV at this age. Maternal obesity reduced Kiss1 expression in all three brain regions of 3 month old female offspring, but only in MePD of males. The role of MePD kisspeptin on puberty, estrous cyclicity and preovulatory LH surges was assessed directly in a separate group of post-weanling and young adult female rats exposed to a normal diet throughout their life course. Bilateral intra-MePD cannulae connected to osmotic mini-pumps for delivery of kisspeptin receptor antagonist (Peptide 234 for 14 days were chronically implanted on pnd 21 or 100. Antagonism of MePD kisspeptin delayed puberty onset, disrupted estrous cyclicity and reduced the incidence of LH surges. These data show that the MePD plays a key role in pubertal timing and ovulation and that maternal obesity may act via amygdala kisspeptin signaling to influence reproductive function in the offspring.

Determination of mating frequency by radiotracer technique

International Nuclear Information System (INIS)

Hamid Miah, M.A.

1978-01-01

Radioisotope ( 32 P) was used to study the frequency of mating of an insect. The radioactivity counts correlated positively with the number of matings. Radioactivity was also detected from the eggs and excised embryos. This work suggests that radioisotope like ( 32 P) may be conveninently used to detect virginity and mating frequency of female insects without killing them. (author)

Variation in male mate choice in Drosophila melanogaster.

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Dominic A Edward

Full Text Available Male mate choice has been reported in the fruit fly, Drosophila melanogaster, even though males of this species were previously thought to maximise their fitness by mating with all available females. To understand the evolution of male mate choice it is important to understand variation in male mating preferences. Two studies, using different stock populations and different methods, have reported contrasting patterns of variation in male mate choice in D. melanogaster. Two possible explanations are that there are evolved differences in each stock population or that the methods used to measure choice could have biased the results. We investigated these hypotheses here by repeating the methods used in one study in which variable male mate choice was found, using the stock population from the other study in which choice was not variable. The results showed a significant resource-independent male preference for less fecund, smaller females, which contrasts with previous observations of male mate choice. This indicates that different selection pressures between populations have resulted in evolved differences in the expression of male mate choice. It also reveals phenotypic plasticity in male mate choice in response to cues encountered in each choice environment. The results highlight the importance of variation in male mate choice, and of identifying mechanisms in order to understand the evolution of mate choice under varying ecological conditions.

Sexual segregation and flexible mating patterns in temperate bats.

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Ruth L Angell

Full Text Available Social structure evolves from a trade-off between the costs and benefits of group-living, which are in turn dependent upon the distribution of key resources such as food and shelter. Males and females, or juveniles and adults, may have different priorities when selecting habitat due to differences in physiological or behavioural imperatives, leading to complex patterns in group composition. We studied social structure and mating behaviour in the insectivorous bat Myotis daubentonii along an altitudinal gradient, combining field studies with molecular genetics. With increasing altitude the proportion of males in summer roosts increased and only males were present in the highest roosts. With increasing altitude environmental temperature decreased, nightly variation in temperature increased, and bat foraging activity decreased, supporting the hypothesis that the harsher, high elevation sites cannot support breeding females. We found that offspring in female-dominated lowland roosts had a very high probability of being fathered by bats caught during autumn swarming at hibernation sites, in contrast to those in intermediate roosts, which had a high probability of being fathered by males sharing the nursery roost with the females. Whilst females normally appear to exclude males from nursery colonies, for those in marginal habitats, one explanation for the presence of males is that the thermoregulatory benefits to the females may outweigh disadvantages, such as competition for food, and give some males an opportunity to increase their breeding success. We suggest that the environment, and its effects on resource distribution, thus determine social structure, which in turn determines the mating pattern that has evolved.

Sexual Cooperation: Mating Increases Longevity in Ant Queens

DEFF Research Database (Denmark)

Schrempf, Alexandra; Heinze, Jürgen; Cremer, Sylvia

2005-01-01

Divergent reproductive interests of males and females often cause sexual conflict [1] and [2] . Males of many species manipulate females by transferring seminal fluids that boost female short-term fecundity while decreasing their life expectancy and future reproductivity [3] and [4] . The life...... history of ants, however, is expected to reduce sexual conflict; whereas most insect females show repeated phases of mating and reproduction, ant queens mate only during a short period early in life and undergo a lifelong commitment to their mates by storing sperm [5] . Furthermore, sexual offspring can...... sterilized male lived considerably longer and started laying eggs earlier than virgin queens. Only queens that received viable sperm from fertile males showed increased fecundity. The lack of a trade-off between fecundity and longevity is unexpected, given evolutionary theories of aging [6] . Our data...

Heterozygosity-based assortative mating in blue tits (Cyanistes caeruleus): implications for the evolution of mate choice

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García-Navas, Vicente; Ortego, Joaquín; Sanz, Juan José

2009-01-01

The general hypothesis of mate choice based on non-additive genetic traits suggests that individuals would gain important benefits by choosing genetically dissimilar mates (compatible mate hypothesis) and/or more heterozygous mates (heterozygous mate hypothesis). In this study, we test these hypotheses in a socially monogamous bird, the blue tit (Cyanistes caeruleus). We found no evidence for a relatedness-based mating pattern, but heterozygosity was positively correlated between social mates, suggesting that blue tits may base their mating preferences on partner's heterozygosity. We found evidence that the observed heterozygosity-based assortative mating could be maintained by both direct and indirect benefits. Heterozygosity reflected individual quality in both sexes: egg production and quality increased with female heterozygosity while more heterozygous males showed higher feeding rates during the brood-rearing period. Further, estimated offspring heterozygosity correlated with both paternal and maternal heterozygosity, suggesting that mating with heterozygous individuals can increase offspring genetic quality. Finally, plumage crown coloration was associated with male heterozygosity, and this could explain unanimous mate preferences for highly heterozygous and more ornamented individuals. Overall, this study suggests that non-additive genetic traits may play an important role in the evolution of mating preferences and offers empirical support to the resolution of the lek paradox from the perspective of the heterozygous mate hypothesis. PMID:19474042

Sex allocation predicts mating rate in a simultaneous hermaphrodite

OpenAIRE

Janicke, Tim; Schärer, Lukas

2009-01-01

Sexual selection theory for separate-sexed animals predicts that the sexes differ in the benefit they can obtain from multiple mating. Conventional sex roles assume that the relationship between the number of mates and the fitness of an individual is steeper in males compared with females. Under these conditions, males are expected to be more eager to mate, whereas females are expected to be choosier. Here we hypothesize that the sex allocation, i.e. the reproductive investment devoted to the...

Multimodal Advertisement of Pregnancy in Free-Ranging Female Japanese Macaques (Macaca fuscata.

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Lucie Rigaill

Full Text Available The role of multiple sexual signals in indicating the timing of female ovulation, and discrimination of this timing by males, has been particularly well studied among primates. However the exhibition of pregnancy signals, and how such signals might modulate male post-conception mating decisions, is still poorly understood. Here we aimed to determine if Japanese macaque males use changes in female sexual signals (behavioral, visual and auditory to discriminate pregnancy and adjust their socio-sexual behaviors. We combined behavioral observations, digital photography and endocrinological (progestogen and estrogen data, collected systematically during three one-month periods: the pre-conceptive period, the 1st month of pregnancy and the 2nd month of pregnancy. We analyzed variation in the probability of detecting male and female socio-sexual behaviors and estrus calls, as well as changes in female face color parameters, in relation to female reproductive state. Based on our focal observations, we found that males did not copulate during the pregnancy period, and that female socio-sexual behaviors generally decreased from the pre-conceptive to post-conceptive periods. Female face luminance decreased from the pre-conceptive month to the pregnancy period whereas face color only varied between the 1st and 2nd month of gestation. Our results suggest that Japanese macaque females display sexual cues of pregnancy that males might use to reduce energy wasted on non-reproductive copulations with pregnant females. We hypothesize that females advertize their pregnancy through changes in behavioral, visual and potential auditory signals that males can use to adjust their mating behaviors. We finish by discussing implications for male and female post-conception strategies.

Genetic variation in social influence on mate preferences

Science.gov (United States)

Rebar, Darren; Rodríguez, Rafael L.

2013-01-01

Patterns of phenotypic variation arise in part from plasticity owing to social interactions, and these patterns contribute, in turn, to the form of selection that shapes the variation we observe in natural populations. This proximate–ultimate dynamic brings genetic variation in social environments to the forefront of evolutionary theory. However, the extent of this variation remains largely unknown. Here, we use a member of the Enchenopa binotata species complex of treehoppers (Hemiptera: Membracidae) to assess how mate preferences are influenced by genetic variation in the social environment. We used full-sibling split-families as ‘treatment’ social environments, and reared focal females alongside each treatment family, describing the mate preferences of the focal females. With this method, we detected substantial genetic variation in social influence on mate preferences. The mate preferences of focal females varied according to the treatment families along with which they grew up. We discuss the evolutionary implications of the presence of such genetic variation in social influence on mate preferences, including potential contributions to the maintenance of genetic variation, the promotion of divergence, and the adaptive evolution of social effects on fitness-related traits. PMID:23698010

Dispersal, mating events and fine-scale genetic structure in the lesser flat-headed bats.

Science.gov (United States)

Hua, Panyu; Zhang, Libiao; Guo, Tingting; Flanders, Jon; Zhang, Shuyi

2013-01-01

Population genetic structure has important consequences in evolutionary processes and conservation genetics in animals. Fine-scale population genetic structure depends on the pattern of landscape, the permanent movement of individuals, and the dispersal of their genes during temporary mating events. The lesser flat-headed bat (Tylonycteris pachypus) is a nonmigratory Asian bat species that roosts in small groups within the internodes of bamboo stems and the habitats are fragmented. Our previous parentage analyses revealed considerable extra-group mating in this species. To assess the spatial limits and sex-biased nature of gene flow in the same population, we used 20 microsatellite loci and mtDNA sequencing of the ND2 gene to quantify genetic structure among 54 groups of adult flat-headed bats, at nine localities in South China. AMOVA and F(ST) estimates revealed significant genetic differentiation among localities. Alternatively, the pairwise F(ST) values among roosting groups appeared to be related to the incidence of associated extra-group breeding, suggesting the impact of mating events on fine-scale genetic structure. Global spatial autocorrelation analyses showed positive genetic correlation for up to 3 km, indicating the role of fragmented habitat and the specialized social organization as a barrier in the movement of individuals among bamboo forests. The male-biased dispersal pattern resulted in weaker spatial genetic structure between localities among males than among females, and fine-scale analyses supported that relatedness levels within internodes were higher among females than among males. Finally, only females were more related to their same sex roost mates than to individuals from neighbouring roosts, suggestive of natal philopatry in females.

Dispersal, mating events and fine-scale genetic structure in the lesser flat-headed bats.

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Panyu Hua

Full Text Available Population genetic structure has important consequences in evolutionary processes and conservation genetics in animals. Fine-scale population genetic structure depends on the pattern of landscape, the permanent movement of individuals, and the dispersal of their genes during temporary mating events. The lesser flat-headed bat (Tylonycteris pachypus is a nonmigratory Asian bat species that roosts in small groups within the internodes of bamboo stems and the habitats are fragmented. Our previous parentage analyses revealed considerable extra-group mating in this species. To assess the spatial limits and sex-biased nature of gene flow in the same population, we used 20 microsatellite loci and mtDNA sequencing of the ND2 gene to quantify genetic structure among 54 groups of adult flat-headed bats, at nine localities in South China. AMOVA and F(ST estimates revealed significant genetic differentiation among localities. Alternatively, the pairwise F(ST values among roosting groups appeared to be related to the incidence of associated extra-group breeding, suggesting the impact of mating events on fine-scale genetic structure. Global spatial autocorrelation analyses showed positive genetic correlation for up to 3 km, indicating the role of fragmented habitat and the specialized social organization as a barrier in the movement of individuals among bamboo forests. The male-biased dispersal pattern resulted in weaker spatial genetic structure between localities among males than among females, and fine-scale analyses supported that relatedness levels within internodes were higher among females than among males. Finally, only females were more related to their same sex roost mates than to individuals from neighbouring roosts, suggestive of natal philopatry in females.

Mutual mate choice: when it pays both sexes to avoid inbreeding.

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Mathieu Lihoreau

Full Text Available Theoretical models of sexual selection predict that both males and females of many species should benefit by selecting their mating partners. However, empirical evidence testing and validating this prediction is scarce. In particular, whereas inbreeding avoidance is expected to induce sexual conflicts, in some cases both partners could benefit by acting in concert and exerting mutual mate choice for non-assortative pairings. We tested this prediction with the gregarious cockroach Blattella germanica (L.. We demonstrated that males and females base their mate choice on different criteria and that choice occurs at different steps during the mating sequence. Males assess their relatedness to females through antennal contacts before deciding to court preferentially non-siblings. Conversely, females biased their choice towards the most vigorously courting males that happened to be non-siblings. This study is the first to demonstrate mutual mate choice leading to close inbreeding avoidance. The fact that outbred pairs were more fertile than inbred pairs strongly supports the adaptive value of this mating system, which includes no "best phenotype" as the quality of two mating partners is primarily linked to their relatedness. We discuss the implications of our results in the light of inbreeding conflict models.

Another Look at Sex Differences in Preferred Mate Characteristics: The Effects of Endorsing the Traditional Female Gender Role

Science.gov (United States)

Johannesen-Schmidt, Mary C.; Eagly, Alice H.

2002-01-01

This research used an individual differences approach to test Eagly and Wood's (1999) claim that sex differences in the characteristics that people prefer in mates reflect the tendency for men and women to occupy different social roles in a society. The study related the extent to which participants endorsed the traditional female gender role to…

Female monopolization and paternity assurance in South American crickets (Orthoptera, Grylloidea: mating plugs, extra claspers and forced copulation

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Francisco de A.G. de Mello

2007-01-01

Full Text Available This paper describes the first three cases in which male crickets monopolize females by means of mating plugs. The origin of the plugs vary among the cases (i.e., they are not homologous. Female monogamy is assured by the permanent presence of the plug attached to their genitalia after first mating, while males are potentially polygamous. The presence of an additional clasping structure and the occurrence of forced copulation are also described.Este trabalho descreve os primeiros três casos em que grilos machos monopolizam suas fêmeas através de plugues de acasalamento. A origem dessas estruturas varia entre os casos (i.e., não há homologia entre as mesmas. A monogamia feminina é assegurada pela presença permanente do plugue de acasalamento aderido a sua genitália após a primeira cópula, enquanto que os machos são potencialmente poligâmicos. Descrevem-se ainda a presença de clásper adicional e a ocorrência de cópulas forçadas.

Thanatosis as an adaptive male mating strategy in the nuptial gift-giving spider Pisaura mirabilis

DEFF Research Database (Denmark)

Hansen, Line S.; Gonzalez, Sofía F.; Toft, Søren

2008-01-01

Males and females often experience different optima in mating rate, which may cause evolution of female resistance to matings and male counter adaptations to increase mating rate. Males of the spider Pisaura mirabilis display a spectacular mating behavior involving a nuptial gift and thanatosis...

Effects of 5-Gy irradiation on fertility and mating behaviour of Nezara viridula (Heteroptera: Pentatomidae)

International Nuclear Information System (INIS)

Zunic, A.; Cokl, A.; Sersa, G.

2002-01-01

Background. The polyphagous and cosmopolitan species Nezara viridula is one of the most important insect pests. The sterile insect technique (SIT) is a pest control strategy that involves sterilising males by exposing them to ionising radiation. Sterile males, released into wild population, mate with females, but eggs are not fertilised and the population gradually declines. Exposing insects to radiation during their growth stage might require lower sterilising dose. The aim of our study was to test whether 5-Gy irradiation of 5 th instar nymphs significantly affects: (1) moulting and further development of the irradiated nymphs, (2) the male's and female's reproductive system and (3) the mating competitiveness of treated males, with special focus on vibrational communication. Methods: The 5 th instar nymphs were irradiated with 5 Gy using X-ray generator and monitored daily. Results: The observed effects of irradiation were: prolonged moulting, increased mortality during development and during the first day of adult life, decreased males to females ratio, decreased fecundity, egg production, proportion of fertile eggs and progeny survival. The reaction of a male to stimulation with the model female calling song was tested. The irradiated and non-irradiated males responded to stimulation with emission of the courtship song (MCrS). Temporal parameters of MCrS emitted by non-irradiated males differed when compared with those of irradiated ones. Conclusions: The 5-Gy irradiation of 5 th instar nymphs did not affect mating behaviour. However since the irradiation during growth stage decreased the fertility and fecundity of emerged adults, this technique, in combination with certain other suppression techniques, could be a successful control strategy for management of Nezara viridula. On the other hand observed effects on moulting and further development of the irradiated nymphs could decrease the efficiency and application of this strategy. (author)

Evolution of sexes from an ancestral mating-type specification pathway.

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Sa Geng

2014-07-01

Full Text Available Male and female sexes have evolved repeatedly in eukaryotes but the origins of dimorphic sexes and their relationship to mating types in unicellular species are not understood. Volvocine algae include isogamous species such as Chlamydomonas reinhardtii, with two equal-sized mating types, and oogamous multicellular species such as Volvox carteri with sperm-producing males and egg-producing females. Theoretical work predicts genetic linkage of a gamete cell-size regulatory gene(s to an ancestral mating-type locus as a possible step in the evolution of dimorphic gametes, but this idea has not been tested. Here we show that, contrary to predictions, a single conserved mating locus (MT gene in volvocine algae-MID, which encodes a RWP-RK domain transcription factor-evolved from its ancestral role in C. reinhardtii as a mating-type specifier, to become a determinant of sperm and egg development in V. carteri. Transgenic female V. carteri expressing male MID produced functional sperm packets during sexual development. Transgenic male V. carteri with RNA interference (RNAi-mediated knockdowns of VcMID produced functional eggs, or self-fertile hermaphrodites. Post-transcriptional controls were found to regulate cell-type-limited expression and nuclear localization of VcMid protein that restricted its activity to nuclei of developing male germ cells and sperm. Crosses with sex-reversed strains uncoupled sex determination from sex chromosome identity and revealed gender-specific roles for male and female mating locus genes in sexual development, gamete fitness and reproductive success. Our data show genetic continuity between the mating-type specification and sex determination pathways of volvocine algae, and reveal evidence for gender-specific adaptations in the male and female mating locus haplotypes of Volvox. These findings will enable a deeper understanding of how a master regulator of mating-type determination in an ancestral unicellular species was

Investigation on mating habit and sexual competition ability of Helicoverpa armigera sterilized by irradiation

International Nuclear Information System (INIS)

Xia Darong; Yang Rongxin; Gu Weiping; Zhang Yanjun

1999-01-01

Mating habit and sexual competition ability of Helicoverpa armigera irradiated with 300 Gy of γ-rays were observed. The results showed that when reared in laboratory, most adults mated at 4-7 o'clock, a small proportion of adults mated at 2-3 o'clock or at 8-9 o'clock in the morning, meanwhile wild population mated two and a half hours earlier than laboratory populations did. No difference in mating habit and sexual competition ability was found between the irradiation-sterilized and normal adults except that the effective mating rate of the former was 61.6%, one third less than that of the latter ones. Most irradiation-sterilized adults mated one time in their whole lives, only a few could mate 2-3 times and even 5 times, indicating that the multi-mating characteristic of Helicoverpa armigera was not changed by irradiation. It can be concluded that irradiated sterile insect technique is feasible for integrated controlling the cotton bollworm

Sexual transmission of a plant pathogenic bacterium, Candidatus Liberibacter asiaticus, between conspecific insect vectors during mating.

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Rajinder S Mann

Full Text Available Candidatus Liberibacter asiaticus is a fastidious, phloem-inhabiting, gram-negative bacterium transmitted by Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae. The bacterium is the presumed causal agent of huanglongbing (HLB, one of the most destructive and economically important diseases of citrus. We investigated whether Las is transmitted between infected and uninfected D. citri adults during courtship. Our results indicate that Las was sexually transmitted from Las-infected male D. citri to uninfected females at a low rate (<4% during mating. Sexual transmission was not observed following mating of infected females and uninfected males or among adult pairs of the same sex. Las was detected in genitalia of both sexes and also in eggs of infected females. A latent period of 7 days or more was required to detect the bacterium in recipient females. Rod shaped as well as spherical structures resembling Las were observed in ovaries of Las-infected females with transmission electron microscopy, but were absent in ovaries from uninfected D. citri females. The size of the rod shaped structures varied from 0.39 to 0.67 µm in length and 0.19 to 0.39 µm in width. The spherical structures measured from 0.61 to 0.80 µm in diameter. This investigation provides convincing evidence that a plant pathogenic bacterium is sexually transmitted from male to female insects during courtship and established evidence that bacteria persist in reproductive organs. Moreover, these findings provide an alternative sexually horizontal mechanism for the spread of Las within populations of D. citri, even in the absence of infected host trees.

The influence of male takeovers on female dispersal in Colobus vellerosus.

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Sicotte, Pascale; Teichroeb, Julie A; Vayro, Josie V; Fox, Stephanie A; Bădescu, Iulia; Wikberg, Eva C

2017-07-01

Male takeovers affect male tenure, female mate choice and ultimately, individual reproductive success in group-living primates. In social systems with female philopatry and high male reproductive skew, male takeovers largely determine female mate choice, whereas in species with female dispersal, females have the option of deserting a new male. We focused on a species with facultative female dispersal to investigate which factors promote female desertion of males after takeover, using 15 cases (12 for which we have complete data on the takeover process and the female dispersal outcome). These cases took place in nine groups of Colobus vellerosus between 2001 and 2013 at the Boabeng-Fiema Monkey Sanctuary, Ghana. Quick takeovers were usually achieved by single adult males and were never followed by female dispersal. Slow takeovers involved several males, and these takeovers were regularly accompanied by female emigration. Infant attacks and infanticide by males occurred during both kinds of takeovers, but females with dependent offspring never dispersed, regardless of whether their infant was attacked or killed by the new male(s). Subadult females, who were not constrained by the presence of infants, dispersed more often after slow takeovers than after quick takeovers. Whether female dispersal post-takeover is an expression of female mate choice, or occurs to avoid the social upheaval surrounding slow takeovers, remains to be investigated. Am. J. Primatol. 79:e22436, 2017. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Site fidelity, mate fidelity, and breeding dispersal in American kestrels

Science.gov (United States)

Steenhof, K.; Peterson, B.E.

2009-01-01

We assessed mate fidelity, nest-box fidelity, and breeding dispersal distances of American Kestrels (falco sparverius) nesting in boxes in southwestern Idaho from 1990 through 2006. Seventy-seven percent of boxes had different males and 87% had different females where nest-box occupants were identified in consecutive years. High turnover rates were partly a result of box-switching. Forty-eight percent of males and 58% of females that nested within the study area in successive years used different boxes. The probability of changing boxes was unrelated to gender, nesting success in the prior year, or years of nesting experience. Breeding dispersal distances for birds that moved to different boxes averaged 2.2 km for males (max = 22 km) and 3.2 km for females (max = 32 km). Approximately 70% of birds that nested in consecutive years on the study area had a different mate in the second year. Mate fidelity was related to box fidelity but not to prior nesting success or years of nesting experience. Mate changes occurred 32% of the time when the previous mate was known to be alive and nesting in the area. Kestrels that switched mates and boxes did not improve or decrease their subsequent nesting success. Kestrels usually switched to mates with less experience and lower lifetime productivity than their previous mates. The costs of switching boxes and mates were low, and there were no obvious benefits to fidelity. The cost of "waiting" for a previous mate that might have died could be high in species with high annual mortality.

Are high-quality mates always attractive? State-dependent mate preferences in birds and humans

NARCIS (Netherlands)

Riebel, Katharina; Holveck, Marie-Jeanne; Verhulst, Simon; Fawcett, Tim W.

2010-01-01

Sexual selection theory posits that females should choose mates in a way that maximizes their reproductive success. But what exactly is the optimal choice? Most empirical research is based on the assumption that females seek a male of the highest possible quality (in terms of the genes or resources

Studies on the ecology of insects sterilized artificially (gamma radiation), 6. Mating competitiveness between the /sup 137/Cs gamma-substerile males reared artificially and natural ones of the tobacco cutworms

Energy Technology Data Exchange (ETDEWEB)

Kiyoku, M; Tsukuda, R [Okayama Univ. (Japan). Faculty of Agriculture

1973-10-01

Two different inbred lines of tobacco cutworms were used for the present experiments. One was a line reared on an artificial medium during the larval period, and the other was reared on leaves of the taro plants. Male pupae from the former medium were irradiated with 12 kR of gamma rays from /sup 137/Cs to substerilize. Other males and females from the latter were not irradiated. From one to four substerilized adults with one normal male were exposed to one normal female in a fixed mating-oviposition jar or cage for investigating the male mating competitiveness and mating behavior between substerilized and normal. In the experiments using substerilized adults less than two with one normal male were exposed to one female in the jar, the hatch percentages of eggs were more than 41.7%. It might not be fully competitive. When four substerile and one normal males were combined with one normal female, however, the percentage in the egg hatch was 5.6%. The value obtained was significantly lower than the theoretical estimation of hatch percentage, and this indicates that substerilized males had been mated more than normal. The result was considered to be fully competitive based on the percentage of egg hatch. Besides that, number of eggs laid in this combination showed a considerable reduction as compared with the control.

Experimental studies on the sterile male technique of spodoptera litura (F. ) by the gamma radiation from /sup 137/Cs, 3. Experiments of the mating competitiveness between moths irradiated as pupae and unirradiated ones in the field cage

Energy Technology Data Exchange (ETDEWEB)

Tsukuda, R; Kiyoku, M [Okayama Univ. (Japan). Faculty of Agriculture

1973-10-01

Experiments of the mating competitiveness between the substerilized tobacco cutworms and the normal ones were carried out in a field cage (200 x 120 x 180 cm/plot). Pupae of seven days old reared on an artificial medium during the larval stage irradiated with 12 kR of the gamma rays to substerilize. The normal adults were cultured using leaves of cabbages. Cabbages and soybeans were planted in the purpose of egg laying for adult females mated with males in the cage. Substerilized males only or both substerilized males and females were combined with normal males and females. The mating behavior, longevity, egg deposition, percentage of egg hatch and spermatophore in a receptaculum seminis were investigated. When more than ten substerilized and one normal males were exposed to one female, or more than fourteen substerilized and two normal males were combined two normal females, the substerilized males showed high competitiveness with normal males for virgin females. When both five substerilized males and females placed together with one pair of normal male and female in the cage, or each ten substerilized males and females with each two normals, these substerilized males showed full competitiveness. In addition, it was found that offspring obtained from the combination between substerilized males and normal females were sterile.

Resistance evolution to Bt crops: predispersal mating of European corn borers.

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Ambroise Dalecky

2006-06-01

Full Text Available Over the past decade, the high-dose refuge (HDR strategy, aimed at delaying the evolution of pest resistance to Bacillus thuringiensis (Bt toxins produced by transgenic crops, became mandatory in the United States and is being discussed for Europe. However, precopulatory dispersal and the mating rate between resident and immigrant individuals, two features influencing the efficiency of this strategy, have seldom been quantified in pests targeted by these toxins. We combined mark-recapture and biogeochemical marking over three breeding seasons to quantify these features directly in natural populations of Ostrinia nubilalis, a major lepidopteran corn pest. At the local scale, resident females mated regardless of males having dispersed beforehand or not, as assumed in the HDR strategy. Accordingly, 0-67% of resident females mating before dispersal did so with resident males, this percentage depending on the local proportion of resident males (0% to 67.2%. However, resident males rarely mated with immigrant females (which mostly arrived mated, the fraction of females mating before dispersal was variable and sometimes substantial (4.8% to 56.8%, and there was no evidence for male premating dispersal being higher. Hence, O. nubilalis probably mates at a more restricted spatial scale than previously assumed, a feature that may decrease the efficiency of the HDR strategy under certain circumstances, depending for example on crop rotation practices.

Mating-induced sexual inhibition in the jumping spider Servaea incana (Araneae: Salticidae: A fast-acting and long-lasting effect.

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Vivian Mendez

Full Text Available Mating-induced sexual inhibition has been studied extensively as an important facet of many insect mating systems but remains little understood in spiders. Once mated, females of many spider species become unreceptive and aggressive toward males, but the speed of onset and persistence of this effect are not known. Addressing this gap, the present study considers (1 mating tendency of virgins, latency to remating, and lifetime mating frequency and (2 how quickly sexual inhibition is expressed after the first mating in female Servaea incana jumping spiders. Encounters between males and females took place in two contexts that simulated locations where mating occurs in nature: in the light away from nests ('in the open' and in low light within the shelter of silken retreats ('at a retreat'. Virgin females exhibited high receptivity levels in both contexts but sexual inhibition was induced immediately after their first copulation. The most common tendency was for just one mating in a lifetime, and few females mated more than twice. Context also had an effect on female mating tendency, as virgin females in the open rejected more males before accepting their first mate than did virgin females in retreats. Considering only those females that did remate, females in the open tended to reject fewer males before remating. Given low levels of female remating, virgin females appear to be at a premium for male reproductive fitness in S. incana jumping spiders and this is a likely explanation for protandry found in nature.

UV-deprived coloration reduces success in mate acquisition in male sand lizards (Lacerta agilis.

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Mats Olsson

Full Text Available Recent work on animal signals has revealed a wide occurrence of UV signals in tetrapods, in particular birds, but also in lizards (and perhaps other Squamate reptiles. Our previous work on the Swedish sand lizard (Lacerta agilis has verified, both in correlative selection analyses in the wild and with laboratory and field experiments, the importance of the green 'badge' on the body sides of adult males for securing mating opportunities, probably mostly through deterring rival males rather than attracting females. The role of UV in communication has, however, never been examined.Here we show that when measured immediately after spring skin shedding, there is also signaling in the UV. By UV-depriving the signal (reflectance with sun block chemicals fixated with permeable, harmless spray dressing, we show that males in the control group (spray dressing only had significantly higher success in mate acquisition than UV-deprived males.These results suggest that at least two colour traits in sand lizards, badge area and UV, contribute to rival deterrence and/or female choice on UV characters, which elevates success in mate acquisition in UV intact male sand lizards.

Marmosets treated with oxytocin are more socially attractive to their long-term mate

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Jon eCavanaugh

2015-10-01

Full Text Available Adult male-female bonds are partly characterized by initiating and maintaining close proximity with a social partner, as well as engaging in high levels of affiliative and sociosexual behavior. Oxytocin (OXT, a neuromodulatory nonapeptide, plays a critical role in the facilitation of social bonding and prosocial behavior toward a social partner (Feldman, 2012. However, less attention has been given to whether augmentation of OXT levels in an individual alters others’ perceptions and behavior toward an OXT-treated social partner. We examined social dynamics in well-established male-female pairs of marmoset monkeys (Callithrix jacchus in which one member of the pair was administered an intranasal OXT agonist, an OXT antagonist, or saline. OXT treatment did not alter the expression of affiliative toward an untreated partner. However, OXT did significantly influence the expression of proximity and grooming behavior with a treated partner, as a function of OXT treatment and sex. Female interest in initiating and maintaining proximity with a pair-mate was altered by OXT treatment. Untreated female marmosets departed from their saline-treated partner more frequently than they approached them, as indicated by a low proximity index score. However, when males received an intranasal OXT agonist they had a significantly increased proximity index score relative to saline, indicating that their untreated partner approached them more often than they departed from them. Saline-treated females initiated and received equivalent levels of grooming behavior. However, when female marmosets were treated with an OXT agonist their untreated partner groomed them proportionately more often, for a greater total duration, and for more time per bout, than they initiated grooming behavior. These results suggest that intranasal OXT altered male and female marmosets’ stimulus properties in such a way as to increase the amount of grooming behavior that females received from

Sterilization studies on the adult indian meal moth, plodia interpunctella (HUBNER)

International Nuclear Information System (INIS)

Boshra, S.A.; Hasaballa, Z.A.

1993-01-01

The effects of gamma radiation doses ranging between 10 and 65 krad on adult plodia interpunctella (Hubner) were studied. Irradiation of adult affected clearly the egg production and fertility of both sexes at different mating combinations. Females were more sensitive to the sterilizing effects of gamma radiation than males. Complete sterility of females and males was achieved at 50 and 65 krad, respectively. Replacing normal males by sterile ones in the normal population decreased the egg hatch ability when compared with the control population. Newly emerged unmated females laid completely infertile eggs when confined with irradiated (65 krad) males, whether mating occurred on the day of treatment or 2 days after treatment. Sterilized males were able to compete with normal ones in a population at the highest flooding ratios. Adding sterile females to this competing population gave excellent results.5 tab

Nest-mate recognition in Manuelia postica (Apidae: Xylocopinae): an eusocial trait is present in a solitary bee

OpenAIRE

Flores-Prado, Luis; Aguilera-Olivares, Daniel; Niemeyer, Hermann M

2007-01-01

In eusocial Hymenoptera, females are more tolerant towards nest-mate than towards non-nest-mate females. In solitary Hymenoptera, females are generally aggressive towards any conspecific female. Field observations of the nest biology of Manuelia postica suggested nest-mate recognition. Experiments were performed involving two live interacting females or one live female interacting with a dead female. Live females from different nests were more intolerant to each other than females from the sa...

Body size and mating success in Drosophila willistoni are ...

Indian Academy of Sciences (India)

Mating activity and wing length were investigated in the F1 progeny of Drosophila willistoni females collected in the field to examine any possible relationship between body size and mating success. The flies were observed in a mating chamber under laboratory conditions. No significant differences in wing length were ...

Coevolving parasites and population size shape the evolution of mating behaviour

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Kerstes Niels AG

2013-02-01

Full Text Available Abstract Background Coevolution with parasites and population size are both expected to influence the evolution of mating rates. To gain insights into the interaction between these dual selective factors, we used populations from a coevolution experiment with the red flour beetle, Tribolium castaneum, and its microsporidian parasite, Nosema whitei. We maintained each experimental population at two different population sizes. We assayed the mating behaviour of both males and females from coevolved and paired non-coevolved control populations after 24 generations of coevolution with parasites. Results Males from large, coevolved populations (i.e. ancestors were exposed to parasites showed a reduced eagerness to mate compared to males from large, non-coevolved populations. But in small populations, coevolution did not lead to decreased male mating rates. Coevolved females from both large and small populations appeared to be more willing to accept mating than non-coevolved females. Conclusions This study provides unique, experimental insights into the combined roles of coevolving parasites and population size on the evolution of mating rate. Furthermore, we find that males and females respond differently to the same environmental conditions. Our results show that parasites can be key determinants of the sexual behaviour of their hosts.

Mating systems and sexual selection in male-pregnant pipefishes and seahorses: insights from microsatellite-based studies of maternity.

Science.gov (United States)

Jones, A G; Avise, J C

2001-01-01

In pipefishes and seahorses (family Syngnathidae), the males provide all postzygotic care of offspring by brooding embryos on their ventral surfaces. In some species, this phenomenon of male "pregnancy" results in a reversal of the usual direction of sexual selection, such that females compete more than males for access to mates, and secondary sexual characteristics evolve in females. Thus the syngnathids can provide critical tests of theories related to the evolution of sex differences and sexual selection. Microsatellite-based studies of the genetic mating systems of several species of pipefishes and seahorses have provided insights into important aspects of the natural history and evolution of these fishes. First, males of species with completely enclosed pouches have complete confidence of paternity, as might be predicted from parental investment theory for species in which males invest so heavily in offspring. Second, a wide range of genetic mating systems have been documented in nature, including genetic monogamy in a seahorse, polygynandry in two species of pipefish, and polyandry in a third pipefish species. The genetic mating systems appear to be causally related to the intensity of sexual selection, with secondary sex characters evolving most often in females of the more polyandrous species. Third, genetic studies of captive-breeding pipefish suggest that the sexual selection gradient (or Bateman gradient) may be a substantially better method for characterizing the mating system than previously available techniques. Finally, these genetic studies of syngnathid mating systems have led to some general insights into the occurrence of clustered mutations at microsatellite loci, the utility of linked loci in studies of parentage, and the use of parentage data for direct estimation of adult population size.

Boll weevils: field and laboratory assessment of mating ability and sperm content after irradiation with or without diflubenzuron treatment

International Nuclear Information System (INIS)

Villavaso, E.J.; Earle, N.W.; Hollier, D.D.

1977-01-01

Sperm depletion did not occur within the 1st week after irradiated males and females of Anthonomus grandis Boheman were released together into isolated field plots. Also, survival and mating ability did not differ as a result of treatment. The treatments were: irradiation of 4-day-old adults plus diflubenzuron (N-(4-chlorophenyl). N 1 -(2,6-difluorobenzoyl) urea)), fractionated irradiation of pupae, and fractionated irradiation of adults plus diflubenzuron

Quantitative Trait Locus Analysis of Mating Behavior and Male Sex Pheromones in Nasonia Wasps

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Wenwen Diao

2016-06-01

Full Text Available A major focus in speciation genetics is to identify the chromosomal regions and genes that reduce hybridization and gene flow. We investigated the genetic architecture of mating behavior in the parasitoid wasp species pair Nasonia giraulti and Nasonia oneida that exhibit strong prezygotic isolation. Behavioral analysis showed that N. oneida females had consistently higher latency times, and broke off the mating sequence more often in the mounting stage when confronted with N. giraulti males compared with males of their own species. N. oneida males produce a lower quantity of the long-range male sex pheromone (4R,5S-5-hydroxy-4-decanolide (RS-HDL. Crosses between the two species yielded hybrid males with various pheromone quantities, and these males were used in mating trials with females of either species to measure female mate discrimination rates. A quantitative trait locus (QTL analysis involving 475 recombinant hybrid males (F2, 2148 reciprocally backcrossed females (F3, and a linkage map of 52 equally spaced neutral single nucleotide polymorphism (SNP markers plus SNPs in 40 candidate mating behavior genes revealed four QTL for male pheromone amount, depending on partner species. Our results demonstrate that the RS-HDL pheromone plays a role in the mating system of N. giraulti and N. oneida, but also that additional communication cues are involved in mate choice. No QTL were found for female mate discrimination, which points at a polygenic architecture of female choice with strong environmental influences.

Mating competitiveness of irradiated males and females of the indian meal moth (Lepidoptera: Pyralidae)

International Nuclear Information System (INIS)

Brower, J.H.

1978-01-01

One-day-old adults of the Indian meal moth, Plodia interpunctella (Huebner), were irradiated (I) with either 35 krad (a partially sterilizing dose) or 50 krad (a sterilizing dose) and combined with untreated (U) adults at numbers of 1, 5, 10, 15, or 25 treated males or females per pair of untreated adults. At 25 males per pair, egg hatch was reduced to 4.8 and 22.2% at 35 and 50 krad, respectively. The calculated degree of competitiveness showed that both males and females were more competitive after treatment with 35 krad than after treatment with 50 krad and that treated females were more competitive (based on percentage egg hatch) at both doses than corresponding males. Irradiated females were fully competitive at most release ratios, but I males were not fully competitive even at the higher release ratios, although the decreases were not large enough to seriously affect their use for field control. (author)

Sexually transmitted bacteria affect female cloacal assemblages in a wild bird

Science.gov (United States)

White, Joël; Mirleau, Pascal; Danchin, Etienne; Mulard, Hervé; Hatch, Scott A.; Heeb, Phillipp; Wagner, Richard H.

2010-01-01

Sexual transmission is an important mode of disease propagation, yet its mechanisms remain largely unknown in wild populations. Birds comprise an important model for studying sexually transmitted microbes because their cloaca provides a potential for both gastrointestinal pathogens and endosymbionts to become incorporated into ejaculates. We experimentally demonstrate in a wild population of kittiwakes (Rissa tridactyla) that bacteria are transmitted during copulation and affect the composition and diversity of female bacterial communities. We used an anti-insemination device attached to males in combination with a molecular technique (automated ribosomal intergenic spacer analysis) that describes bacterial communities. After inseminations were experimentally blocked, the cloacal communities of mates became increasingly dissimilar. Moreover, female cloacal diversity decreased and the extinction of mate-shared bacteria increased, indicating that female cloacal assemblages revert to their pre-copulatory state and that the cloaca comprises a resilient microbial ecosystem.

Nutritional effects on reproductive performance of captive adult female coyotes (Canis latrans).

Science.gov (United States)

Gese, Eric M; Roberts, Beth M; Knowlton, Frederick F

2016-02-01

Interactions between animals and their environment are fundamental to ecological research. Field studies of coyote (Canis latrans) reproductive performance suggest mean litter size changes in response to prey abundance. However, this relationship has been assessed primarily by using carcasses collected from trappers. The objective of this study was to assess whether nutritional manipulation prior to mating affected reproduction in adult female coyotes. We examined the effects of caloric restriction during the 7 months prior to estrus on the reproductive rates of 11 captive female coyotes and the subsequent initial survival of pups through two reproductive cycles. This was a 2-year study with a cross-over design so each female was monitored for reproductive performance on each of the two diet treatments. We assessed the number of implantation scars, number of pups born, sex ratios of pups, average pup weight at birth and 2- and 6-weeks of age, and the survival rates between implantation and 2-weeks of age for two diet treatments. We found the mean number of implantation sites and pups whelped during a reproductive cycle was influenced by food-intake prior to conception. Additionally, we found evidence suggesting the effects of nutritional stress may persist for additional breeding cycles. We also provided evidence suggesting well-fed females tended to have more male pups. Understanding how environmental factors influence reproductive output may improve model predictions of coyote population dynamics. Published by Elsevier B.V.

Postlarval development of Halicarcinus planatus females (Crustacea, Decapoda, Hymenosomatidae in the estuary of the Deseado River, Argentina

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Julio H. Vinuesa

2008-03-01

Full Text Available This study analyses morphology and morphometric growth changes of Halicarcinus planatus females until their terminal moult, and characterises new juvenile stages. Monthly samples were collected in the estuary of the Deseado River, Santa Cruz Province, Argentina. Crabs were sampled between the mid-intertidal and upper subtidal levels. Intermoult stages were analysed in sub-samples of adolescents and adults, and the presence of epizoic organisms was registered. Juveniles and adults were reared at the laboratory and examined for moult changes. All 3376 crabs caught were females, indicating a clear spatial segregation between sexes. Five juvenile stages (immature 1, 2, 3, 4 and adolescent and a mature one were recognised on the basis of morphology and morphometry. All immature stages differed in cephalothorax width (CW and abdomen width (AW. Positive allometry was observed in some juvenile stages and isometry in an immature stage and in mature females. Adolescents and adults encompassed a wide range of sizes, and the considerable size overlap between them suggests an anomalous growth process. Moult staging analysis indicated that adolescents have a high incidence of pre-moult stages in winter, when the terminal moult occurs. The measurements performed in laboratory-reared females indicated no abnormal increases during the moult. The terminal moult occurs within a wide size range, perhaps in association with mating.

Differential investment in pre- vs. post-copulatory sexual selection reinforces a cross-continental reversal of sexual size dimorphism in Sepsis punctum (Diptera: Sepsidae).

Science.gov (United States)

Puniamoorthy, Nalini; Blanckenhorn, W U; Schäfer, M A

2012-11-01

Theory predicts that males have a limited amount of resources to invest in reproduction, suggesting a trade-off between traits that enhance mate acquisition and those that enhance fertilization success. Here, we investigate the relationship between pre- and post-copulatory investment by comparing the mating behaviour and reproductive morphology of four European and five North American populations of the dung fly Sepsis punctum (Diptera) that display a reversal of sexual size dimorphism (SSD). We show that the geographic reversal in SSD between the continents (male biased in Europe, female biased in North America) is accompanied by differential investment in pre- vs. post-copulatory traits. We find higher remating rates in European populations, where larger males acquire more matings and consequently have evolved relatively larger testes and steeper hyper-allometry with body size. American populations, in sharp contrast, display much reduced, if any, effect of body size on those traits. Instead, North American males demonstrate an increased investment in mate acquisition prior to copulation, with more mounting attempts and a distinctive abdominal courtship display that is completely absent in Europe. When controlling for body size, relative female spermathecal size is similar on both continents, so we find no direct evidence for the co-evolution of male and female internal reproductive morphology. By comparing allopatric populations of the same species that apparently have evolved different mating systems and consequently SSD, we thus indirectly demonstrate differential investment in pre- vs. post-copulatory mechanisms increasing reproductive success. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Mating success and sexual selection in a pelagic copepod, Temora longicornis: Evidence from paternity analyses

DEFF Research Database (Denmark)

Sichlau, Mie Hylstofte; Eg Nielsen, Einar; Thygesen, Uffe Høgsbro

2015-01-01

Knowledge about mating patterns is essential for understanding and explaining rates of reproduction and genetic potential of copepods populations. The aim of this study was to examine (1) the occurrence of multiple paternity in Temora longicornis, (2) the effect of multiple paternity (if present......) on the females reproductive output, and (3) whether mating is random or some individuals have a higher than average chance of fertilizing or being fertilized (super individuals). We show that multiple paternity is common in this copepod species, that females benefit from multiple matings by increased offspring...... production, and that a relatively small fraction of the males and females in a population account for most of the offspring production. In both males and females, mating is nonrandom. Superior individuals with a higher than average matings success were identified both among females and among males....

Evidence of late-summer mating readiness and early sexual maturation in migratory tree-roosting bats found dead at wind turbines

Science.gov (United States)

Cryan, P.M.; Jameson, J.W.; Baerwald, E.F.; Willis, C.K.R.; Barclay, R.M.R.; Snider, E.A.; Crichton, E.G.

2012-01-01

Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans) found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines.

Evidence of late-summer mating readiness and early sexual maturation in migratory tree-roosting bats found dead at wind turbines.

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Paul M Cryan

Full Text Available Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus, eastern red bats (L. borealis, and silver-haired bats (Lasionycteris noctivagans found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines.

Evidence of late-summer mating readiness and early sexual maturation in migratory tree-roosting bats found dead at wind turbines.

Science.gov (United States)

Cryan, Paul M; Jameson, Joel W; Baerwald, Erin F; Willis, Craig K R; Barclay, Robert M R; Snider, E Apple; Crichton, Elizabeth G

2012-01-01

Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans) found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines.

The cost of mating: influences of life history traits and mating strategies on lifespan in two closely related Yponomeuta species

NARCIS (Netherlands)

Bakker, A.C.; Campos Louçã, J.; Roessingh, P.; Menken, S.B.J.

2011-01-01

Theory predicts that in monandrous butterfly species males should not invest in a long lifespan because receptive females quickly disappear from the mating population. In polyandrous species, however, it pays for males to invest in longevity, which increases the number of mating opportunities and

Mating competitiveness of Aedes albopictus radio-sterilized males in large enclosures exposed to natural conditions.

Science.gov (United States)

Bellini, R; Balestrino, F; Medici, A; Gentile, G; Veronesi, R; Carrieri, M

2013-01-01

Mating competitiveness trials have been conducted in large net-screened enclosures (8 by 5 by 2.8 m) built in a natural shaded environment, in the summers of 2006, 2007, 2008, and 2009 in northern Italy. Aedes albopictus (Skuse) males were radio-sterilized by applying gamma radiations at doses in the range 30-60 Gy. Gamma radiation was administered to aged pupae at the rate of 2.3 Gy/min. Reared radiated males (originally collected in Rimini, Forli, Bologna, Matera, Pinerolo) and hybrid radiated males were tested against wild fertile males (originated from eggs collected in Rimini and Cesena) and reared fertile males, in multiple comparisons for mating competitiveness with reared or wild females. The ratio was kept constant at 100-100_100 (fertile males-radiated males_virgin females). Mating competitiveness was estimated through the calculation of the hatching rate of the eggs laid in oviposition traps positioned inside enclosures. No clear effect of the strains tested (reared, wild, or hybrid) was found. Results demonstrated that reducing the radiation dose from 60 to 30 Gy increases males' competitiveness. Laboratory investigations conducted after controversial results in the 2006 preliminary trials, showed that radiation induces precociousness in adult male emergence.

Effect of mate size on maternal reproductive effort in the convict cichlid Amatitlania siquia

Institute of Scientific and Technical Information of China (English)

Ashley R. ROBART

2012-01-01

The differential allocation hypothesis predicts individuals will increase their reproductive investment when mated to a high quality partner.In many species of fish with biparental care females prefer large males due to the males' greater ability to raise more offspring to independence.I examined the relationship between mate quality,parental care and number of offspring in a natural population of convict cichlids Amatitlania siquia.The frequency of frontal displays by females was positively correlated with male standard length.Additionally,as males increased in length relative to their mate,females increased the frequency of chases towards predators,while males decreased the number of displays towards brood predators.This trade-off in parental effort within a pair due to mate quality is a key prediction of differential allocation.The number of offspring was correlated with male,but not female,standard length.These results support the differential allocation hypothesis in that females offered more parental care to offspring of a larger male,while their mates decreased the amount of care they provided.Additionally,females benefited in terms of number of offspring by pairing with higher quality mates.Increased female investment may provide an incentive to ensure male care and maintain pair bonding,which could lead to greater reproductive success through increased offspring survival [Current Zoology 58 (1):66-72,2012].

Effect of mate size on maternal reproductive effort in the convict cichlid Amatitlania siquia

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Ashley R. ROBART

2012-02-01

Full Text Available The differential allocation hypothesis predicts individuals will increase their reproductive investment when mated to a high quality partner. In many species of fish with biparental care females prefer large males due to the males’ greater ability to raise more offspring to independence. I examined the relationship between mate quality, parental care and number of offspring in a natural population of convict cichlids Amatitlania siquia. The frequency of frontal displays by females was positively correlated with male standard length. Additionally, as males increased in length relative to their mate, females increased the frequency of chases towards predators, while males decreased the number of displays towards brood predators. This trade-off in parental effort within a pair due to mate quality is a key prediction of differential allocation. The number of offspring was correlated with male, but not female, standard length. These results support the differential allocation hypothesis in that females offered more parental care to offspring of a larger male, while their mates decreased the amount of care they provided. Additionally, females benefited in terms of number of offspring by pairing with higher quality mates. Increased female investment may provide an incentive to ensure male care and maintain pair bonding, which could lead to greater reproductive success through increased offspring survival [Current Zoology 58 (1: 66–72, 2012].

Molecular assessment of mating strategies in a population of Atlantic spotted dolphins.

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Michelle L Green

Full Text Available Similar to other small cetacean species, Atlantic spotted dolphins (Stenella frontalis have been the object of concentrated behavioral study. Although mating and courtship behaviors occur often and the social structure of the population is well-studied, the genetic mating system of the species is unknown. To assess the genetic mating system, we genotyped females and their progeny at ten microsatellite loci. Genotype analysis provided estimates of the minimum number of male sires necessary to account for the allelic diversity observed among the progeny. Using the estimates of male sires, we determined whether females mated with the same or different males during independent estrus events. Using Gerud2.0, a minimum of two males was necessary to account for the genetic variation seen among progeny arrays of all tested females. ML-Relate assigned the most likely relationship between offspring pairs; half or full sibling. Relationship analysis supported the conservative male estimates of Gerud2.0 but in some cases, half or full sibling relationships between offspring could not be fully resolved. Integrating the results from Gerud2.0, ML-Relate with previous observational and paternity data, we constructed two-, three-, and four-male pedigree models for each genotyped female. Because increased genetic diversity of offspring may explain multi-male mating, we assessed the internal genetic relatedness of each offspring's genotype to determine whether parent pairs of offspring were closely related. We found varying levels of internal relatedness ranging from unrelated to closely related (range -0.136-0.321. Because there are several hypothesized explanations for multi-male mating, we assessed our data to determine the most plausible explanation for multi-male mating in our study system. Our study indicated females may benefit from mating with multiple males by passing genes for long-term viability to their young.

Discrete two-sex models of population dynamics: On modelling the mating function

Science.gov (United States)

Bessa-Gomes, Carmen; Legendre, Stéphane; Clobert, Jean

2010-09-01

Although sexual reproduction has long been a central subject of theoretical ecology, until recently its consequences for population dynamics were largely overlooked. This is now changing, and many studies have addressed this issue, showing that when the mating system is taken into account, the population dynamics depends on the relative abundance of males and females, and is non-linear. Moreover, sexual reproduction increases the extinction risk, namely due to the Allee effect. Nevertheless, different studies have identified diverse potential consequences, depending on the choice of mating function. In this study, we investigate the consequences of three alternative mating functions that are frequently used in discrete population models: the minimum; the harmonic mean; and the modified harmonic mean. We consider their consequences at three levels: on the probability that females will breed; on the presence and intensity of the Allee effect; and on the extinction risk. When we consider the harmonic mean, the number of times the individuals of the least abundant sex mate exceeds their mating potential, which implies that with variable sex-ratios the potential reproductive rate is no longer under the modeller's control. Consequently, the female breeding probability exceeds 1 whenever the sex-ratio is male-biased, which constitutes an obvious problem. The use of the harmonic mean is thus only justified if we think that this parameter should be re-defined in order to represent the females' breeding rate and the fact that females may reproduce more than once per breeding season. This phenomenon buffers the Allee effect, and reduces the extinction risk. However, when we consider birth-pulse populations, such a phenomenon is implausible because the number of times females can reproduce per birth season is limited. In general, the minimum or modified harmonic mean mating functions seem to be more suitable for assessing the impact of mating systems on population dynamics.

Arrhenotoky and oedipal mating in the northern fowl mite (Ornithonyssus sylviarum (Acari: Gamasida: Macronyssidae

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McCulloch John B

2012-12-01

Full Text Available Abstract Background The northern fowl mite (NFM; Ornithonyssus sylviarum is a blood-feeding ectoparasite of birds and a major pest of poultry in the United States. Mite populations spread rapidly in commercial flocks, reach peak burdens of >70,000 mites per bird and have developed resistance to many pesticides. Despite decades as a pest in the United States, the reproductive biology of NFM remains unclear. Based on karyotypes, the NFM has haplodiploid sex determination, which suggests unmated females could produce male offspring (arrhenotoky. Thus, unmated females could disseminate to a new host and initiate an infestation by producing and mating with sons (oedipal mating. Methods We used small capsules to isolate and recover NFM on host chickens. Mites in capsules could blood feed, develop and reproduce, but could not contact other mites. Individual larvae were matured in isolation to produce known, unmated females. We evaluated reproduction of (I previously mated females (i in isolation, or (ii paired with a male, and (II unmated (virgin females in isolation. In each treatment we recorded the number and sexes of offspring produced over time. Results Mated NFM produced female and male offspring in isolation, or when paired with a male. When paired with a male, females produced a female-biased sex ratio of the offspring (F:M ratio ~5:1. Unmated, female NFM produced exclusively male offspring when in isolation. When paired with their sons that had developed to maturity, the "virgin" females were able to mate and subsequently produce female offspring. Conclusions This study found that females with immediate access to sperm produced mostly female offspring. Virgin female NFM initially produced only male offspring and subsequently used oedipal mating to produce female offspring. Using this reproductive system NFM could successfully colonize new hosts as immature, or unmated females. The strong female-biased sex ratio of NFM populations suggests a

Fitness of Mass-Reared Males of Anastrepha obliqua (Diptera: Tephritidae) Resulting From Mating Competition Tests in Field Cages.

Science.gov (United States)

Hernández, Emilio; Liedo, Pablo; Toledo, Jorge; Montoya, Pablo; Perales, Hugo; Ruiz-Montoya, Lorena

2017-12-05

The sterile insect technique uses males that have been mass-reared in a controlled environment. The insects, once released in the field, must compete to mate. However, the mass-rearing condition supposes a loss of fitness that will be noticeable by wild females. To compare the fitness of wild males and mass-reared males, three competition settings were established. In setting 1, wild males, mass-reared males and wild females were released in field cages. In setting 2, wild females and wild males were released without competition, and in setting 3, mass-reared males and mass-reared females were also released without competition. Male fitness was based on their mating success, fecundity, weight and longevity. The fitness of the females was measured based on weight and several demographic parameters. The highest percentage of mating was between wild males and wild females between 0800 and 0900 h in the competition condition, while the mass-reared males started one hour later. The successful wild males weighed more and showed longer mating times, greater longevity and a higher number of matings than the mass-reared males. Although the mass-reared males showed the lowest percentage of matings, their fecundity when mating with wild females indicated a high fitness. Since the survival and fecundity of wild females that mated with mass-reared males decreased to become similar to those of mass-reared females that mated with mass-reared males, females seem to be influenced by the type of male (wild or mass-reared). © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A synthesized mating pheromone component increases adult sea lamprey (Petromyzon marinus) trap capture in management scenarios

Science.gov (United States)

Johnson, Nicholas S.; Siefkes, Michael J.; Wagner, C. Michael; Dawson, Heather; Wang, Huiyong; Steeves, Todd; Twohey, Michael; Li, Weiming

2013-01-01

Application of chemical cues to manipulate adult sea lamprey (Petromyzon marinus) behavior is among the options considered for new sea lamprey control techniques in the Laurentian Great Lakes. A male mating pheromone component, 7a,12a,24-trihydroxy-3-one-5a-cholan-24-sulfate (3kPZS), lures ovulated female sea lamprey upstream into baited traps in experimental contexts with no odorant competition. A critical knowledge gap is whether this single pheromone component influences adult sea lamprey behavior in management contexts containing free-ranging sea lampreys. A solution of 3kPZS to reach a final in-stream concentration of 10-12 mol·L-1 was applied to eight Michigan streams at existing sea lamprey traps over 3 years, and catch rates were compared between paired 3kPZS-baited and unbaited traps. 3kPZS-baited traps captured significantly more sexually immature and mature sea lampreys, and overall yearly trapping efficiency within a stream averaged 10% higher during years when 3kPZS was applied. Video analysis of a trap funnel showed that the likelihood of sea lamprey trap entry after trap encounter was higher when the trap was 3kPZS baited. Our approach serves as a model for the development of similar control tools for sea lamprey and other aquatic invaders.

Experimental studies on the sterile male technique of Spodoptera litura (F.) by the gamma radiation from 137Cs, 4

International Nuclear Information System (INIS)

Tsukuda, Ritsuko; Kiyoku, Masao

1975-01-01

Present studies have been carried out to examine two phenomena by the mating experiment under laboratory conditions. One was the influence of age of adult males or females on the mating behaviour, the number of eggs laid by females and the percentage of egg hatching. The other was the mating capacity of males when a male was confined with three or five females in a mating cage during fixed periods. Younger and middle ages have no influence on the mating. The influence of old age on females was greater than on males. When one day old females were mated with more than eight day old males, the mating was delayed slightly, both the number of eggs laid by females and percentage of egg hatching were decreased, respectively. When one day old males were combined with more than seven day old females, however, the mating was hindered and no viable eggs were laid. One adult male was confined with three adult females in a mating cage. At each mating experiment, one male was able to mate with one from three females during one night, or with two or three females during three nights. One spermatophore was always observed in a female mated already. When one adult male was confined with five adult females, he mated with one female during one night, with two females during three nights, or with three or four females during five nights. (author)

High costs of female choice in a lekking lizard.

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Maren N Vitousek

2007-06-01

Full Text Available Although the cost of mate choice is an essential component of the evolution and maintenance of sexual selection, the energetic cost of female choice has not previously been assessed directly. Here we report that females can incur high energetic costs as a result of discriminating among potential mates. We used heart rate biologging to quantify energetic expenditure in lek-mating female Galápagos marine iguanas (Amblyrhynchus cristatus. Receptive females spent 78.9+/-23.2 kJ of energy on mate choice over a 30-day period, which is equivalent to approximately (3/4 of one day's energy budget. Females that spent more time on the territories of high-quality, high-activity males displayed greater energetic expenditure on mate choice, lost more mass, and showed a trend towards producing smaller follicles. Choosy females also appear to face a reduced probability of survival if El Niño conditions occur in the year following breeding. These findings indicate that female choice can carry significant costs, and suggest that the benefits that lek-mating females gain through mating with a preferred male may be higher than previously predicted.

Commensal Bacteria Aid Mate-selection in the Fruit Fly, Bactrocera dorsalis.

Science.gov (United States)

Damodaram, Kamala Jayanthi Pagadala; Ayyasamy, Arthikirubha; Kempraj, Vivek

2016-10-01

Commensal bacteria influence many aspects of an organism's behaviour. However, studies on the influence of commensal bacteria in insect mate-selection are scarce. Here, we present empirical evidence that commensal bacteria mediate mate-selection in the Oriental fruit fly, Bactrocera dorsalis. Male flies were attracted to female flies, but this attraction was abolished when female flies were fed with antibiotics, suggesting the role of the fly's microbiota in mediating mate-selection. We show that male flies were attracted to and ejaculated more sperm into females harbouring the microbiota. Using culturing and 16S rDNA sequencing, we isolated and identified different commensal bacteria, with Klebsiella oxytoca being the most abundant bacterial species. This preliminary study will enhance our understanding of the influence of commensal bacteria on mate-selection behaviour of B. dorsalis and may find use in devising control operations against this devastating pest.

A study on domestic violence against adult and adolescent females in a rural area of West Bengal

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Sarkar Madhutandra

2010-01-01

Full Text Available Background: Globally, domestic violence against females is common across culture, religion, class and ethnicity. There are various reasons for domestic violence and it might have serious health outcomes. Objectives: The study was undertaken to determine the prevalence, characteristics, reasons and the socio-demographic correlates of domestic violence, if any, and to find out the perceptions of the females to cope with the act of violence and to overcome the situation. Materials and Methods: A cross-sectional observational study was undertaken by interviewing 141 adult and adolescent females residing in a village of West Bengal, with the help of a pre-designed and pre-tested questionnaire. Data were analyzed statistically by simple proportions and tests of significance (Chi-square test. Results: Out of 141 respondents, 33 (23.4% adult and adolescent females in this village were exposed to domestic violence in the past year. Among the demographic characteristics, statistically significant maximum prevalence was observed among 30-39 years age group, illiterate and unmarried females. For most of the females who were exposed to domestic violence, their husbands acted as the perpetrators (72.73% and they reported slapping as the specific act of physical assault (72.73%. Majority of the respondents reported that opportunity of education (31.9%, being economically productive (31.9% and better family income (23.4% would help them to overcome the situation. Conclusion: This study emphasizes the need for justified female empowerment and this calls for multidisciplinary approach to develop public health measures, which would most effectively address the problem of domestic violence.

Intra- and trans-generational costs of reduced female body size caused by food limitation early in life in mites.

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Andreas Walzer

Full Text Available Food limitation early in life may be compensated for by developmental plasticity resulting in accelerated development enhancing survival at the expense of small adult body size. However and especially for females in non-matching maternal and offspring environments, being smaller than the standard may incur considerable intra- and trans-generational costs.Here, we evaluated the costs of small female body size induced by food limitation early in life in the sexually size-dimorphic predatory mite Phytoseiulus persimilis. Females are larger than males. These predators are adapted to exploit ephemeral spider mite prey patches. The intra- and trans-generational effects of small maternal body size manifested in lower maternal survival probabilities, decreased attractiveness for males, and a reduced number and size of eggs compared to standard-sized females. The trans-generational effects of small maternal body size were sex-specific with small mothers producing small daughters but standard-sized sons.Small female body size apparently intensified the well-known costs of sexual activity because mortality of small but not standard-sized females mainly occurred shortly after mating. The disadvantages of small females in mating and egg production may be generally explained by size-associated morphological and physiological constraints. Additionally, size-assortative mate preferences of standard-sized mates may have rendered small females disproportionally unattractive mating partners. We argue that the sex-specific trans-generational effects were due to sexual size dimorphism - females are the larger sex and thus more strongly affected by maternal stress than the smaller males - and to sexually selected lower plasticity of male body size.

Intra- and trans-generational costs of reduced female body size caused by food limitation early in life in mites.

Science.gov (United States)

Walzer, Andreas; Schausberger, Peter

2013-01-01

Food limitation early in life may be compensated for by developmental plasticity resulting in accelerated development enhancing survival at the expense of small adult body size. However and especially for females in non-matching maternal and offspring environments, being smaller than the standard may incur considerable intra- and trans-generational costs. Here, we evaluated the costs of small female body size induced by food limitation early in life in the sexually size-dimorphic predatory mite Phytoseiulus persimilis. Females are larger than males. These predators are adapted to exploit ephemeral spider mite prey patches. The intra- and trans-generational effects of small maternal body size manifested in lower maternal survival probabilities, decreased attractiveness for males, and a reduced number and size of eggs compared to standard-sized females. The trans-generational effects of small maternal body size were sex-specific with small mothers producing small daughters but standard-sized sons. Small female body size apparently intensified the well-known costs of sexual activity because mortality of small but not standard-sized females mainly occurred shortly after mating. The disadvantages of small females in mating and egg production may be generally explained by size-associated morphological and physiological constraints. Additionally, size-assortative mate preferences of standard-sized mates may have rendered small females disproportionally unattractive mating partners. We argue that the sex-specific trans-generational effects were due to sexual size dimorphism - females are the larger sex and thus more strongly affected by maternal stress than the smaller males - and to sexually selected lower plasticity of male body size.

Does the contraceptive pill alter mate choice in humans?

Science.gov (United States)

Alvergne, Alexandra; Lummaa, Virpi

2010-03-01

Female and male mate choice preferences in humans both vary according to the menstrual cycle. Women prefer more masculine, symmetrical and genetically unrelated men during ovulation compared with other phases of their cycle, and recent evidence suggests that men prefer ovulating women to others. Such monthly shifts in mate preference have been suggested to bring evolutionary benefits in terms of reproductive success. New evidence is now emerging that taking the oral contraceptive pill might significantly alter both female and male mate choice by removing the mid-cycle change in preferences. Here, we review support for such conclusions and speculate on the consequences of pill-induced choice of otherwise less-preferred partners for relationship satisfaction, durability and, ultimately, reproductive outcomes.

Modelling the evolution and consequences of mate choice

OpenAIRE

Tazzyman, S. J.

2010-01-01

This thesis considers the evolution and the consequences of mate choice across a variety of taxa, using game theoretic, population genetic, and quantitative genetic modelling techniques. Part I is about the evolution of mate choice. In chapter 2, a population genetic model shows that mate choice is even beneficial in self-fertilising species such as Saccharomyces yeast. In chapter 3, a game theoretic model shows that female choice will be strongly dependent upon whether the benefi...

Multi-Generational Kinship, Multiple Mating, and Flexible Modes of Parental Care in a Breeding Population of the Veery (Catharus fuscescens, a Trans-Hemispheric Migratory Songbird.

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Matthew R Halley

Full Text Available We discovered variable modes of parental care in a breeding population of color-banded Veeries (Catharus fuscescens, a Nearctic-Neotropical migratory songbird, long thought to be socially monogamous, and performed a multi-locus DNA microsatellite analysis to estimate parentage and kinship in a sample of 37 adults and 21 offspring. We detected multiple mating in both sexes, and four modes of parental care that varied in frequency within and between years including multiple male feeders at some nests, and males attending multiple nests in the same season, each with a different female. Unlike other polygynandrous systems, genetic evidence indicates that multi-generational patterns of kinship occur among adult Veeries at our study site, and this was corroborated by the capture of an adult male in 2013 that had been banded as a nestling in 2011 at a nest attended by multiple male feeders. All genotyped adults (n = 37 were related to at least one other bird in the sample at the cousin level or greater (r ≥ 0.125, and 81% were related to at least one other bird at the half-sibling level or greater (r ≥ 0.25, range 0.25-0.60. Although our sample size is small, it appears that the kin structure is maintained by natal philopatry in both sexes, and that Veeries avoid mating with close genetic kin. At nests where all adult feeders were genotyped (n = 9, the male(s were unrelated to the female (mean r = -0.11 ± 0.15, whereas genetic data suggest close kinship (r = 0.254 between two male co-feeders at the nests of two females in 2011, and among three of four females that were mated to the same polygynous male in 2012. To our knowledge, this is the first evidence of polygynandry occurring among multiple generations of close genetic kin on the breeding ground of a Nearctic-Neotropical migratory songbird.

Multi-year evaluation of mating disruption treatments against gypsy moth

Science.gov (United States)

Patrick C. Tobin; Kevin W. Thorpe; Laura M. Blackburn

2007-01-01

Mating disruption is the use of synthetic pheromone flakes that are aerially applied to foliage with the goal of interfering with male gypsy moths? ability to locate females and mate. Mating disruption is the primary tactic against gypsy moth used in the Gypsy Moth Slow-the-Spread Project (STS) [Tobin et al. 2004. Amer. Entomol. 50:200].

Maternal effects on male weaponry: female dung beetles produce major sons with longer horns when they perceive higher population density

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Buzatto Bruno A

2012-07-01

Full Text Available Abstract Background Maternal effects are environmental influences on the phenotype of one individual that are due to the expression of genes in its mother, and are expected to evolve whenever females are better capable of assessing the environmental conditions that their offspring will experience than the offspring themselves. In the dung beetle Onthophagus taurus, conditional male dimorphism is associated with alternative reproductive tactics: majors fight and guard females whereas minors sneak copulations. Furthermore, variation in dung beetle population density has different fitness consequences for each male morph, and theory predicts that higher population density might select for a higher frequency of minors and/or greater expenditure on weaponry in majors. Because adult dung beetles provide offspring with all the nutritional resources for their development, maternal effects strongly influence male phenotype. Results Here we tested whether female O. taurus are capable of perceiving population density, and responding by changing the phenotype of their offspring. We found that mothers who were reared with other conspecifics in their pre-mating period produced major offspring that had longer horns across a wider range of body sizes than the major offspring of females that were reared in isolation in their pre-mating period. Moreover, our results indicate that this maternal effect on male weaponry does not operate through the amount of dung provided by females to their offspring, but is rather transmitted through egg or brood mass composition. Finally, although theory predicts that females experiencing higher density might produce more minor males, we found no support for this, rather the best fitting models were equivocal as to whether fewer or the same proportions of minors were produced. Conclusions Our study describes a new type of maternal effect in dung beetles, which probably allows females to respond to population density adaptively

Evaluation of the Mating Competitiveness of the Adult Oriental Fruit Fly Reared as Larvae in Liquid vs. Those Raised on Standard Wheat-based Diets

Science.gov (United States)

Three strains (standard lab, DTWP pupal color sexing strain and wild strain) of adult oriental fruit flies, which were reared as larvae on a liquid diet, mill feed diet (Tanaka’s diet), or natural host fruit diet, were evaluated for mating competitiveness in both indoor and outdoor Boller’s mating c...

Sex-biased parental investment is correlated with mate ornamentation in eastern bluebirds.

Science.gov (United States)

Ligon, Russell A; Hill, Geoffrey E

2010-03-01

Males typically have greater variance in reproductive success than females, so mothers should benefit by producing sons under favorable conditions. Being paired with a better-than-average mate is one such favorable circumstance. High-quality fathers can improve conditions for their offspring by providing good genes, good resources, or both, so females paired to such males should invest preferentially in sons. Ornamentation has been linked to male quality in many birds and, in support of differential allocation theory, females of several avian species invest more in entire broods when paired to attractive mates. Additionally, the females of some bird species apparently manipulate the primary sex-ratio of their broods in relation to the attractiveness of their mates. However, empirical support for a link between mate ornamentation and preferential feeding of sons (another form of biased investment) is lacking. We tested for correlations between sex-biased parental investment and mate plumage colour in the eastern bluebird (Sialia sialis), a species in which juveniles have sexually dichromatic UV-blue plumage. We found that the proportion of maternal feeding attempts to fledgling sons (versus fledgling daughters) was positively correlated with structurally coloured plumage ornamentation of fathers. Additionally, paternal feeding attempts to sons were correlated with plumage ornamentation of mothers and increased in fathers exhibiting breast plumage characteristics typical of older males. These results provide further support for the idea that parental strategies are influenced by mate attractiveness and provide the first evidence that mate ornamentation can influence parental behavior even after offspring have left the nest.

Intrasexual competition facilitates the evolution of alternative mating strategies in a colour polymorphic fish.

Science.gov (United States)

Hurtado-Gonzales, Jorge L; Uy, J Albert C

2010-12-23

Intense competition for access to females can lead to males exploiting different components of sexual selection, and result in the evolution of alternative mating strategies (AMSs). Males of Poecilia parae, a colour polymorphic fish, exhibit five distinct phenotypes: drab-coloured (immaculata), striped (parae), structural-coloured (blue) and carotenoid-based red and yellow morphs. Previous work indicates that immaculata males employ a sneaker strategy, whereas the red and yellow morphs exploit female preferences for carotenoid-based colours. Mating strategies favouring the maintenance of the other morphs remain to be determined. Here, we report the role of agonistic male-male interactions in influencing female mating preferences and male mating success, and in facilitating the evolution of AMSs. Our study reveals variation in aggressiveness among P. parae morphs during indirect and direct interactions with sexually receptive females. Two morphs, parae and yellow, use aggression to enhance their mating success (i.e., number of copulations) by 1) directly monopolizing access to females, and 2) modifying female preferences after winning agonistic encounters. Conversely, we found that the success of the drab-coloured immaculata morph, which specializes in a sneak copulation strategy, relies in its ability to circumvent both male aggression and female choice when facing all but yellow males. Strong directional selection is expected to deplete genetic variation, yet many species show striking genetically-based polymorphisms. Most studies evoke frequency dependent selection to explain the persistence of such variation. Consistent with a growing body of evidence, our findings suggest that a complex form of balancing selection may alternatively explain the evolution and maintenance of AMSs in a colour polymorphic fish. In particular, this study demonstrates that intrasexual competition results in phenotypically distinct males exhibiting clear differences in their levels of

Intrasexual competition facilitates the evolution of alternative mating strategies in a colour polymorphic fish

Directory of Open Access Journals (Sweden)

Uy J Albert C

2010-12-01

Full Text Available Abstract Background Intense competition for access to females can lead to males exploiting different components of sexual selection, and result in the evolution of alternative mating strategies (AMSs. Males of Poecilia parae, a colour polymorphic fish, exhibit five distinct phenotypes: drab-coloured (immaculata, striped (parae, structural-coloured (blue and carotenoid-based red and yellow morphs. Previous work indicates that immaculata males employ a sneaker strategy, whereas the red and yellow morphs exploit female preferences for carotenoid-based colours. Mating strategies favouring the maintenance of the other morphs remain to be determined. Here, we report the role of agonistic male-male interactions in influencing female mating preferences and male mating success, and in facilitating the evolution of AMSs. Results Our study reveals variation in aggressiveness among P. parae morphs during indirect and direct interactions with sexually receptive females. Two morphs, parae and yellow, use aggression to enhance their mating success (i.e., number of copulations by 1 directly monopolizing access to females, and 2 modifying female preferences after winning agonistic encounters. Conversely, we found that the success of the drab-coloured immaculata morph, which specializes in a sneak copulation strategy, relies in its ability to circumvent both male aggression and female choice when facing all but yellow males. Conclusions Strong directional selection is expected to deplete genetic variation, yet many species show striking genetically-based polymorphisms. Most studies evoke frequency dependent selection to explain the persistence of such variation. Consistent with a growing body of evidence, our findings suggest that a complex form of balancing selection may alternatively explain the evolution and maintenance of AMSs in a colour polymorphic fish. In particular, this study demonstrates that intrasexual competition results in phenotypically distinct

Age- and size-dependent mating performance and fertility in a pelagic copepod, Temora longicornis

DEFF Research Database (Denmark)

Sichlau, Mie Hylstofte; Kiørboe, Thomas

2011-01-01

Prepress abstract: In many species, size and age have been shown to be strong determinants of the reproductive success for both sexes. Here we examine age- and size dependent reproductive performance (egg- and sperm production, mating success) in a pelagic copepod. Compared to smaller males, larger...... males produce larger spermatophores containing more spermatozoa, and fertilize a larger fraction of available females. Females mating with large males produce more offspring than those mating with small males. Similarly, large females have higher egg production rates as well as a higher life-time egg...... fertilize females for only about eight days after they mature. The strong size- and age-dependent fertility observed in this species is conducive to the development of sexual selection via mate choice for young and large partners, as has been shown in one other copepod species...

Selection on male size, leg length and condition during mate search in a sexually highly dimorphic orb-weaving spider.

Science.gov (United States)

Foellmer, Matthias W; Fairbairn, Daphne J

2005-02-01

Mate search plays a central role in hypotheses for the adaptive significance of extreme female-biased sexual size dimorphism (SSD) in animals. Spiders (Araneae) are the only free-living terrestrial taxon where extreme SSD is common. The "gravity hypothesis" states that small body size in males is favoured during mate search in species where males have to climb to reach females, because body length is inversely proportional to achievable speed on vertical structures. However, locomotive performance of males may also depend on relative leg length. Here we examine selection on male body size and leg length during mate search in the highly dimorphic orb-weaving spider Argiope aurantia, using a multivariate approach to distinguish selection targeted at different components of size. Further, we investigate the scaling relationships between male size and energy reserves, and the differential loss of reserves. Adult males do not feed while roving, and a size-dependent differential energy storage capacity may thus affect male performance during mate search. Contrary to predictions, large body size was favoured in one of two populations, and this was due to selection for longer legs. Male size was not under selection in the second population, but we detected direct selection for longer third legs. Males lost energy reserves during mate search, but this was independent of male size and storage capacity scaled isometrically with size. Thus, mate search is unlikely to lead to selection for small male size, but the hypothesis that relatively longer legs in male spiders reflect a search-adapted morphology is supported.

Online Female Escort Advertisements

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James D. Griffith

2016-05-01

Full Text Available Female escorts represent an occupational group that charges a fee for sex, which can be regarded as an extreme form of short-term mating. The present study examined if the fees charged by escorts are related to traits typically associated with female short-term mate value. A total of 2,925 advertisements for female escorts offering sexual services in the United States were examined, as a customized software program was used to download all the advertisements from an online escort directory. The advertisement content was coded, and relationships between advertised physical characteristics and the hourly rate charged by female escorts were examined. The analyses showed that higher fees were associated with female escorts who advertised a waist-to-hip ratio near 0.7, lower weight and body mass index, younger age, and photographic displays of breast and buttocks nudity. The findings provide evidence that evolutionarily relevant traits associated with female short-term mate value are systematically related to fees charged for sexual services.

Adolescent Female Cannabinoid Exposure Diminishes the Reward-Facilitating Effects of Δ9-Tetrahydrocannabinol and d-Amphetamine in the Adult Male Offspring

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George Panagis

2017-04-01

Full Text Available Marijuana is currently the most commonly abused illicit drug. According to recent studies, cannabinoid use occurring prior to pregnancy can impact brain plasticity and behavior in future generations. The purpose of the present study was to determine whether adolescent exposure of female rats to Δ9-tetrahydrocannabinol (Δ9-THC induces transgenerational effects on the reward-facilitating effects of Δ9-THC and d-amphetamine in their adult male offspring. Female Sprague-Dawley rats received Δ9-THC (0.1 or 1 mg/kg, i.p. or vehicle during postnatal days 28–50. As adults, females were mated with drug-naïve males. We then assessed potential alterations of the Δ9-THC’s (0, 0.1, 0.5, and 1 mg/kg, i.p. and d-amphetamine’s (0, 0.1, 0.5, and 1 mg/kg, i.p. reward-modifying effects using the curve-shift variant of the intracranial self-stimulation (ICSS procedure in their adult male F1 offspring. The reward-facilitating effect of the 0.1 mg dose of Δ9-THC was abolished in the F1 offspring of females that were exposed to Δ9-THC (0.1 or 1 mg/kg, whereas the reward-attenuating effect of the 1 mg dose of Δ9-THC remained unaltered. The reward-facilitating effects of 0.5 and 1 mg of d-amphetamine were significantly decreased in the F1 offspring of females that were exposed to Δ9-THC (1 mg/kg and 0.1 or 1 mg, respectively. The present results reveal that female Δ9-THC exposure during adolescence can diminish the reward-facilitating effects of Δ9-THC and d-amphetamine in the adult male offspring. These transgenerational effects occur in the absence of in utero exposure. It is speculated that Δ9-THC exposure during female adolescence may affect neural mechanisms that are shaping reward-related behavioral responses in a subsequent generation, as indicated by the shifts in the reward-facilitating effects of commonly used and abused drugs.

Viability of the miss-sexed female pupae in the process of application of sterile insect technique of male oriental fruit fly, Bactrocera dorsalis (Hendel)

International Nuclear Information System (INIS)

Ji Qing'e; Du Yinggang; Hou Weirong; Chen Jiahua

2008-01-01

Female pupae came from the genetic sexing strain (GSS) of Bactrocera dorsalis (Hendel) were irradiated by 60 Co at 1d, 2d and 3d separately before emergence and the dosage were 90, 100 and 105Gy. The emergence percentage, flight ability and survival percentage under stress were tested. The irradiated female adults mated with unirradiated males and irradiated males came from GSS after emergence, the number of eggs and egg hatch rates were scored for each treatment at 10d and 17d separately. The results showed that the quality control trend of irradiated female were the same as the irradiated male. The irradiated female did not lay egg when mated with irradiated male. The number of eggs decreased sharp when the irradiated females mated with unirradiated males, and the number of eggs would decrease with the increase of irradiation dosage and decrease of pupae age. (authors)

Frequency-dependence of mating success in Poeciliopsis monacha (Pisces, Cyprinodontiformes reproductive complex, Sonora, Mexico

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Lima Neuza Rejane Wille

2002-01-01

Full Text Available A diversity of all-female fishes of the genus Poeciliopsis coexists with their sexual ancestor species in streams of western Mexico. All-females are hybrids that depend on the sperm of paternal species to reproduce. Rare-female advantage is one of several hypotheses that attempt to explain how the diversity of all-female biotypes is maintained within the Poeciliopsis reproductive complexes. According to this hypothesis, the uncommon all-female biotype has a mating advantage over the common ones and has been maintained by a dynamic equilibrium process. In the P. monacha reproductive complex at Arroyo de los Platanos the density of two all-female biotypes (P. 2monacha-lucida I and II varies across pools. The objective of this study was to analyse fecundity and mating success of females from this arroyo to test the hypothesis. Female mating success was inversely correlated to their density, supporting this hypothesis.

No evidence for the effect of MHC on male mating success in the brown bear.

Science.gov (United States)

Kuduk, Katarzyna; Babik, Wieslaw; Bellemain, Eva; Valentini, Alice; Zedrosser, Andreas; Taberlet, Pierre; Kindberg, Jonas; Swenson, Jon E; Radwan, Jacek

2014-01-01

Mate choice is thought to contribute to the maintenance of the spectacularly high polymorphism of the Major Histocompatibility Complex (MHC) genes, along with balancing selection from parasites, but the relative contribution of the former mechanism is debated. Here, we investigated the association between male MHC genotype and mating success in the brown bear. We analysed fragments of sequences coding for the peptide-binding region of the highly polymorphic MHC class I and class II DRB genes, while controlling for genome-wide effects using a panel of 18 microsatellite markers. Male mating success did not depend on the number of alleles shared with the female or amino-acid distance between potential mates at either locus. Furthermore, we found no indication of female mating preferences for MHC similarity being contingent on the number of alleles the females carried. Finally, we found no significant association between the number of MHC alleles a male carried and his mating success. Thus, our results provided no support for the role of mate choice in shaping MHC polymorphism in the brown bear.

Intra- and Trans-Generational Costs of Reduced Female Body Size Caused by Food Limitation Early in Life in Mites

Science.gov (United States)

Walzer, Andreas; Schausberger, Peter

2013-01-01

Background Food limitation early in life may be compensated for by developmental plasticity resulting in accelerated development enhancing survival at the expense of small adult body size. However and especially for females in non-matching maternal and offspring environments, being smaller than the standard may incur considerable intra- and trans-generational costs. Methodology/Principal Findings Here, we evaluated the costs of small female body size induced by food limitation early in life in the sexually size-dimorphic predatory mite Phytoseiulus persimilis. Females are larger than males. These predators are adapted to exploit ephemeral spider mite prey patches. The intra- and trans-generational effects of small maternal body size manifested in lower maternal survival probabilities, decreased attractiveness for males, and a reduced number and size of eggs compared to standard-sized females. The trans-generational effects of small maternal body size were sex-specific with small mothers producing small daughters but standard-sized sons. Conclusions/Significance Small female body size apparently intensified the well-known costs of sexual activity because mortality of small but not standard-sized females mainly occurred shortly after mating. The disadvantages of small females in mating and egg production may be generally explained by size-associated morphological and physiological constraints. Additionally, size-assortative mate preferences of standard-sized mates may have rendered small females disproportionally unattractive mating partners. We argue that the sex-specific trans-generational effects were due to sexual size dimorphism – females are the larger sex and thus more strongly affected by maternal stress than the smaller males – and to sexually selected lower plasticity of male body size. PMID:24265745

Extra-pair mating and evolution of cooperative neighbourhoods.

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Sigrunn Eliassen

Full Text Available A striking but unexplained pattern in biology is the promiscuous mating behaviour in socially monogamous species. Although females commonly solicit extra-pair copulations, the adaptive reason has remained elusive. We use evolutionary modelling of breeding ecology to show that females benefit because extra-pair paternity incentivizes males to shift focus from a single brood towards the entire neighbourhood, as they are likely to have offspring there. Male-male cooperation towards public goods and dear enemy effects of reduced territorial aggression evolve from selfish interests, and lead to safer and more productive neighbourhoods. The mechanism provides adaptive explanations for the common empirical observations that females engage in extra-pair copulations, that neighbours dominate as extra-pair sires, and that extra-pair mating correlates with predation mortality and breeding density. The models predict cooperative behaviours at breeding sites where males cooperate more towards public goods than females. Where maternity certainty makes females care for offspring at home, paternity uncertainty and a potential for offspring in several broods make males invest in communal benefits and public goods. The models further predict that benefits of extra-pair mating affect whole nests or neighbourhoods, and that cuckolding males are often cuckolded themselves. Derived from ecological mechanisms, these new perspectives point towards the evolution of sociality in birds, with relevance also for mammals and primates including humans.

Early social isolation impairs development, mate choice and grouping behaviour of predatory mites.

Science.gov (United States)

Schausberger, Peter; Gratzer, Marian; Strodl, Markus A

2017-05-01

The social environment early in life is a key determinant of developmental, physiological and behavioural trajectories across vertebrate and invertebrate animals. One crucial variable is the presence/absence of conspecifics. For animals usually reared in groups, social isolation after birth or hatching can be a highly stressful circumstance, with potentially long-lasting consequences. Here, we assessed the effects of social deprivation (isolation) early in life, that is, absence of conspecifics, versus social enrichment, that is, presence of conspecifics, on developmental time, body size at maturity, mating behaviour and group-living in the plant-inhabiting predatory mite Phytoseiulus persimilis . Socially deprived protonymphs developed more slowly and were less socially competent in grouping behaviour than socially enriched protonymphs. Compromised social competence in grouping behaviour was evident in decreased activity, fewer mutual encounters and larger interindividual distances, all of which may entail severe fitness costs. In female choice/male competition, socially deprived males mated earlier than socially enriched males; in male choice/female competition, socially deprived females were more likely to mate than socially enriched females. In neither mate choice situation did mating duration or body size at maturity differ between socially deprived and enriched mating opponents. Social isolation-induced shifts in mating behaviour may be interpreted as increased attractiveness or competitiveness or, more likely, as hastiness and reduced ability to assess mate quality. Overall, many of the social isolation-induced behavioural changes in P. persimilis are analogous to those observed in other animals such as cockroaches, fruit flies, fishes or rodents. We argue that, due to their profound and persistent effects, early social deprivation or enrichment may be important determinants in shaping animal personalities.

Effects of gamma irradiation on some major elements and mating competitiveness of the red Palm Weevil, Rhynchophorus Ferrugineus (OLIVIER), Coleoptera : Curculionidae

International Nuclear Information System (INIS)

Mohamed, H.F.; EL-Naggar, S.M.; EL-Kkoly, E.M.S.

2006-01-01

In the present study, effects of three gamma doses (5, 10 and 15 Gray) applied to adult male and female weevils of the red palm weevil, Rhynchophorus ferrugineus (Olivier), were investigated. The concentration levels of sodium, potassium, calcium and phosphorous were determined in the haemolymph treated and untreated F1 progeny (males or females) at the 4th instar larvae descendants from irradiated parents male and female weevils. Results indicated that gamma irradiation might have an effect on most investigated elements. No clear relationship could be detected among the applied doses and effect on the level of any of the studied elements. Male mating competitiveness was determined from the egg infertility resulting from F1 males originating from irradiated parental male weevils confined in various ratios with unirradiated adults. Studies comparing mating performance of irradiated males with that of normal males revealed that the mating competitiveness of the irradiated males was increased as the ratio of irradiated to unirradiated males increased from 1 : 1 to 3 : 1 , except at the lesser dose 5 Gy .The results also showed that the infertility was increased as the ratios increased except at the dose rate 10 Gy . The irradiated males were not fully competitive with normal males at the dose 5 Gy among the two ratios 1 : 1 and 3 : 1 and also among the ratio 1:1 at the doses 10 and 15 Gy. The irradiated males were fully competitive with normal males at the doses 10 and 15 Gy among the ratio 3 : 1

Why men matter: mating patterns drive evolution of human lifespan.

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Shripad D Tuljapurkar

2007-08-01

Full Text Available Evolutionary theory predicts that senescence, a decline in survival rates with age, is the consequence of stronger selection on alleles that affect fertility or mortality earlier rather than later in life. Hamilton quantified this argument by showing that a rare mutation reducing survival is opposed by a selective force that declines with age over reproductive life. He used a female-only demographic model, predicting that female menopause at age ca. 50 yrs should be followed by a sharp increase in mortality, a "wall of death." Human lives obviously do not display such a wall. Explanations of the evolution of lifespan beyond the age of female menopause have proven difficult to describe as explicit genetic models. Here we argue that the inclusion of males and mating patterns extends Hamilton's theory and predicts the pattern of human senescence. We analyze a general two-sex model to show that selection favors survival for as long as men reproduce. Male fertility can only result from matings with fertile females, and we present a range of data showing that males much older than 50 yrs have substantial realized fertility through matings with younger females, a pattern that was likely typical among early humans. Thus old-age male fertility provides a selective force against autosomal deleterious mutations at ages far past female menopause with no sharp upper age limit, eliminating the wall of death. Our findings illustrate the evolutionary importance of males and mating preferences, and show that one-sex demographic models are insufficient to describe the forces that shape human senescence.

Gamma irradiation used on adult Tetranychus urticae Koch as a quarantine treatment

Directory of Open Access Journals (Sweden)

Osouli Shiva

2014-07-01

Full Text Available The effect of gamma radiation with 0, 200, 250, 300, 350, 400, and 450 Gy intensities on the longevity, total number of eggs, and the percent of hatched eggs laid by irradiated females of Tetranychus urticae Koch (Tetranychidae was evaluated. Two different groups (0–24 h old and 48–72 h old of adult females were irradiated. The results showed that 350 and 300 Gy doses significantly reduced the longevity of the 0–24 h old females and the 48–72 h old females. The younger females were more tolerant at lower dose rates than the older females. There was a quadratic relationship between dose rates and young females, while it was linear in older females. The total number of eggs laid by females of both ages was significantly reduced with a linear trend by 250 Gy irradiation. The eggs laid by females of both the 0–24 h olds and the 48–72 h olds lost their hatchability when the dose rate was 350 Gy. It was concluded, that applying a dose rate of 320 Gy on one of the mates (male or female before mating, or a 300 Gy on both of them, would be sufficient to cause sterility in adult mites.

File list: ALL.Adl.50.AllAg.Adult_female [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available ALL.Adl.50.AllAg.Adult_female dm3 All antigens Adult Adult female SRX1084165,SRX025...13111,SRX013105 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/ALL.Adl.50.AllAg.Adult_female.bed ...

File list: Unc.Adl.50.AllAg.Adult_female [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available Unc.Adl.50.AllAg.Adult_female dm3 Unclassified Adult Adult female SRX042248,SRX0130...18,SRX013048 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/assembled/Unc.Adl.50.AllAg.Adult_female.bed ...

Mating with an allopatric male triggers immune response and decreases longevity of ant queens.

Science.gov (United States)

Schrempf, A; von Wyschetzki, K; Klein, A; Schrader, L; Oettler, J; Heinze, J

2015-07-01

In species with lifelong pair bonding, the reproductive interests of the mating partners are aligned, and males and females are expected to jointly maximize their reproductive success. Mating increases both longevity and fecundity of female reproductives (queens) of the ant Cardiocondyla obscurior, indicating a tight co-evolution of mating partners. Here, we show that mating with a male from their own population increases lifespan and reproductive success of queens more than mating with a male from a different population, with whom they could not co-evolve. A comparison of transcriptomes revealed an increased expression of genes involved in immunity processes in queens, which mated with males from a different population. Increased immune response might be proximately associated with decreased lifespan. Our study suggests a synergistic co-evolution between the sexes and sheds light on the proximate mechanisms underlying the decreased fitness of allopatrically mated queens. © 2015 John Wiley & Sons Ltd.

"Nice guys finish last": influence of mate choice on reproductive success in Long-Evans rats.

Science.gov (United States)

Winland, C; Bolton, J L; Ford, B; Jampana, S; Tinker, J; Frohardt, R J; Guarraci, F A; Zewail-Foote, M

2012-02-01

The present study was designed to determine if male physiology and male reproductive behavior predict reproductive success in Long-Evans rats. Mating behavior was observed in sexually naïve, naturally cycling female rats during behavioral estrous that were given the opportunity to mate with two males simultaneously. DNA analysis of offspring born following these mating encounters was used to identify the paternity of each pup. In order to assess the effect of mate choice during these mating encounters on reproductive success, one male rat in each pair was categorized as the preferred mate if the female spent more time (>50%) with him during the mating test of the present study. Furthermore, each male in the pairs was categorized as "attractive" or "non-attractive" by computing the number of females that preferred each male across many mating tests. Similar to results reported in Lovell et al. (2007), during 76% of these mating tests the same male rat in each pair was preferred by different female rats. Overall attractiveness of individual male rats predicted reproductive success in the present study. Interestingly, "attractive" males sired significantly FEWER pups than "non-attractive" males. Neither behavioral (e.g., latency to first sexual stimulation, number of sexual stimulations) nor physiological measures (e.g., body weight, urinary testosterone levels) of male rats predicted their reproductive success. In conclusion, the present results indicate that certain features of some males are more attractive to females, but attractive males are at a reproductive disadvantage (as measured by the number of pups sired). Although basal urinary testosterone levels did not differ between males that sired the majority of pups in a litter and males that sired few or none of the pups in a litter, aggression and/or other physiological measures of fertility (e.g., penile reflexes) may differ between males that are attractive to females and those that have a reproductive

Density-dependent selection on mate search and evolution of Allee effects.

Science.gov (United States)

Berec, Luděk; Kramer, Andrew M; Bernhauerová, Veronika; Drake, John M

2018-01-01

Sexually reproducing organisms require males and females to find each other. Increased difficulty of females finding mates as male density declines is the most frequently reported mechanism of Allee effects in animals. Evolving more effective mate search may alleviate Allee effects, but may depend on density regimes a population experiences. In particular, high-density populations may evolve mechanisms that induce Allee effects which become detrimental when populations are reduced and maintained at a low density. We develop an individual-based, eco-genetic model to study how mating systems and fitness trade-offs interact with changes in population density to drive evolution of the rate at which males or females search for mates. Finite mate search rate triggers Allee effects in our model and we explore how these Allee effects respond to such evolution. We allow a population to adapt to several population density regimes and examine whether high-density populations are likely to reverse adaptations attained at low densities. We find density-dependent selection in most of scenarios, leading to search rates that result in lower Allee thresholds in populations kept at lower densities. This mainly occurs when fecundity costs are imposed on mate search, and provides an explanation for why Allee effects are often observed in anthropogenically rare species. Optimizing selection, where the attained trait value minimizes the Allee threshold independent of population density, depended on the trade-off between search and survival, combined with monogamy when females were searching. Other scenarios led to runaway selection on the mate search rate, including evolutionary suicide. Trade-offs involved in mate search may thus be crucial to determining how density influences the evolution of Allee effects. Previous studies did not examine evolution of a trait related to the strength of Allee effects under density variation. We emphasize the crucial role that mating systems, fitness

Out of Lust or Jealousy: The Effects of Mate-Related Motives on Study-Time Allocation to Faces Varying in Attractiveness.

Science.gov (United States)

Li, Weijian; Zhang, Yuchi; Li, Fengying; Li, Xinyu; Li, Ping; Jia, Xiaoyu; Chen, Haide; Ji, Haojie

2015-01-01

Although a growing number of empirical studies have revealed that activating mate-related motives might exert a specific set of consequences for human cognition and behaviors, such as attention and memory, little is known about whether mate-related motives affect self-regulated learning. The present study examined the effects of mate-related motives (mate-search and mate-guarding) on study-time allocation to faces varying in attractiveness. In two experiments, participants in mate-related priming conditions (Experiment 1: mate-search; Experiment 2: mate-guarding) or control conditions studied 20 female faces (10 highly attractive, 10 less attractive) during a self-paced study task, and then were given a yes/no face recognition task. The finding of Experiment 1 showed that activating a mate-search motive led the male participants to allocate more time to highly attractive female faces (i.e., perceived potential mates) than to less attractive ones. In Experiment 2, female participants in the mate-guarding priming condition spent more time studying highly attractive female faces (i.e., perceived potential rivals) than less attractive ones, compared to participants in the control condition. These findings illustrate the highly specific consequences of mate-related motives on study-time allocation, and highlight the value of exploring human cognition and motivation within evolutionary and self-regulated learning frameworks.

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Does pregnancy coloration reduce female conspecific aggression in the presence of maternal kin?

Science.gov (United States)

Bailey, Andrea; Eberly, Lynn E; Packer, Craig

2015-10-01

Colour signals arise in a variety of sexual contexts, including advertising reproductive status. Despite potentially attracting negative attention from unrelated competitors, bright pregnancy coloration may communicate gestation to kin and potential fathers, thereby garnering aid during agonistic encounters and reducing the overall amount of aggression received by pregnant females. To establish whether this 'pregnancy sign' influences rates of aggression in the presence versus absence of maternal kin, we conducted behavioural observations of wild olive baboons, Papio anubis , in Gombe National Park, Tanzania, in groups composed of maternal kin and nonkin, and of captive baboons at the Southwest National Primate Research Center (SNPRC, San Antonio, TX, U.S.A.), in group enclosures that were unlikely to include close kin. At SNPRC, we also experimentally obscured the coloration of the pregnancy sign, and we performed playback experiments to measure male responses to the distress calls of pregnant females. Free-ranging female baboons experienced significantly less aggression from nonkin females after the onset of the pregnancy sign compared to the pre-pregnancy sign. In contrast, captive pregnant females whose pregnancy coloration was obscured with paint experienced significantly lower aggression rates from female conspecifics compared to pre-painting. Male aggression towards females did not differ in the presence versus absence of the pregnancy sign in either the wild or the captive population, although captive fathers paid significantly more attention to distress calls of pregnant cage-mates than they did to those of cycling cage-mates, suggesting a willingness to aid mothers that were carrying their unborn offspring.

MATE. Multi Aircraft Training Environment

DEFF Research Database (Denmark)

Hauland, G.; Bove, T.; Andersen, Henning Boje

2002-01-01

A medium fidelity and low cost training device for pilots, called the Multi Aircraft Training Environment (MATE), is developed to replace other low fidelity stand-alone training devices and integrate them into a flexible environment, primarily aimed attraining pilots in checklist procedures....../models to be simulated) and with possibilities for including various forms of intelligent computer assistance. This training concept and the technology are not specific toaviation, but can be used to simulate various types of control panels in different domains. The training effectiveness of pilots' procedure training...... in the MATE prototype was compared with the effects of traditional training that included the use of realaircraft. The experimental group (EXP) trained the pre-start checklist and the engine start checklist for the Saab 340 commuter aircraft in a MATE prototype. The control group (CTR) trained the same...

Sexual conflict arising from extrapair matings in birds.

Science.gov (United States)

Chaine, Alexis S; Montgomerie, Robert; Lyon, Bruce E

2015-01-20

The discovery that extrapair copulation (EPC) and extrapair paternity (EPP) are common in birds led to a paradigm shift in our understanding of the evolution of mating systems. The prevalence of extrapair matings in pair-bonded species sets the stage for sexual conflict, and a recent focus has been to consider how this conflict can shape variation in extrapair mating rates. Here, we invert the causal arrow and consider the consequences of extrapair matings for sexual conflict. Extrapair matings shift sexual conflict from a simple two-player (male vs. female) game to a game with three or more players, the nature of which we illustrate with simple diagrams that highlight the net costs and benefits of extrapair matings to each player. This approach helps identify the sorts of traits that might be under selection because of sexual conflict. Whether EPP is driven primarily by the extrapair male or the within-pair female profoundly influences which players are in conflict, but the overall pattern of conflict varies little among different mating systems. Different aspects of conflict are manifest at different stages of the breeding cycle and can be profitably considered as distinct episodes of selection caused by conflict. This perspective is illuminating both because conflict between specific players can change across episodes and because the traits that evolve to mediate conflict likely differ between episodes. Although EPP clearly leads to sexual conflict, we suggest that the link between sexual conflict and multiple paternity might be usefully understood by examining how deviations from lifetime sexual monogamy influence sexual conflict. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

From Environment to Mating Competition and Super-K in a Predominantly Urban Sample of Young Adults

Directory of Open Access Journals (Sweden)

George B. Richardson

2017-02-01

Full Text Available Recent research suggests human life history strategy (LHS may be subsumed by multiple dimensions, including mating competition and Super-K, rather than one. In this study, we test whether a two-dimensional structure best fit data from a predominantly urban sample of young adults ages 18–24. We also test whether latent life history dimensions are associated with environmental harshness and unpredictability as predicted by life history theory. Results provide evidence that a two-dimensional model best fit the data. Furthermore, a moderate inverse residual correlation between mating competition and Super-K was found, consistent with a life history trade-off. Our findings suggest that parental socioeconomic status may enhance investment in mating competition, that harshness might persist into young adulthood as an important correlate of LHS, and that unpredictability may not have significant effects in young adulthood. These findings further support the contention that human LHS is multidimensional and environmental effects on LHS are more complex than previously suggested. The model presented provides a parsimonious explanation of an array of human behaviors and traits and can be used to inform public health initiatives, particularly with respect to the potential impact of environmental interventions.

Characterizing Male–Female Interactions Using Natural Genetic Variation in Drosophila melanogaster

Science.gov (United States)

Reinhart, Michael; Carney, Tara; Clark, Andrew G.

2015-01-01

Drosophila melanogaster females commonly mate with multiple males establishing the opportunity for pre- and postcopulatory sexual selection. Traits impacting sexual selection can be affected by a complex interplay of the genotypes of the competing males, the genotype of the female, and compatibilities between the males and females. We scored males from 96 2nd and 94 3rd chromosome substitution lines for traits affecting reproductive success when mated with females from 3 different genetic backgrounds. The traits included male-induced female refractoriness, male remating ability, the proportion of offspring sired under competitive conditions and male-induced female fecundity. We observed significant effects of male line, female genetic background, and strong male by female interactions. Some males appeared to be “generalists” and performed consistently across the different females; other males appeared to be “specialists” and performed very well with a particular female and poorly with others. “Specialist” males did not, however, prefer to court those females with whom they had the highest reproductive fitness. Using 143 polymorphisms in male reproductive genes, we mapped several genes that had consistent effects across the different females including a derived, high fitness allele in Acp26Aa that may be the target of adaptive evolution. We also identified a polymorphism upstream of PebII that may interact with the female genetic background to affect male-induced refractoriness to remating. These results suggest that natural variation in PebII might contribute to the observed male–female interactions. PMID:25425680

Analise do pre-processamento da erva-mate para chimarrão

OpenAIRE

Agenor Maccari Junior

2005-01-01

Resumo: o cultivo e o processamento da erva-mate (1. paraguariensis) têm importante papel na economia dos Estados do Sul do Brasil, uma vez que tais atividades estão presentes em pequenas propriedades e indústrias, gerando milhares de empregos. Entretanto, o setor enfrenta dificuldades, sendo que as indústrias devem reduzir custos e gastos com energia, mantendo qualidade na produção. Uma alternativa é a adequação da tecnologia utilizada no processamento da erva-mate. Para tanto, este trabalho...

Heterospecific mating and partial prezygotic reproductive isolation in the planktonic marine copepods Centropages typicus and Centropages hamatus

DEFF Research Database (Denmark)

Goetze, Erica

2008-01-01

Using three-dimensional (3D) video observations in laboratory experiments, I describe interspecific and intergeneric mating behaviors and motility patterns of the common planktonic marine copepods Centropages typicus, Centropages hamatus, and Temora longicornis. These observations are then used...... to estimate heterospecific and conspecific male mate-search volume rates and mate encounter rates in North Sea Centropages populations. Behavioral prezygotic reproductive isolation between Centropages species is incomplete, since males of each species pursued, contacted, captured, and, in rare cases, placed...... a spermatophore on the urosome of heterospecific females. T. longicornis males also detected the diffusible pheromone trail and pursued C. typicus females to the point of mate contact. Male mate-search tracking behavior was equally effective on diffusible pheromone trails of heterospecific and conspecific females...

Status and Mating Success Amongst Visual Artists

Science.gov (United States)

Clegg, Helen; Nettle, Daniel; Miell, Dorothy

2011-01-01

Geoffrey Miller has hypothesized that producing artwork functions as a mating display. Here we investigate the relationship between mating success and artistic success in a sample of 236 visual artists. Initially, we derived a measure of artistic success that covered a broad range of artistic behaviors and beliefs. As predicted by Miller’s evolutionary theory, more successful male artists had more sexual partners than less successful artists but this did not hold for female artists. Also, male artists with greater artistic success had a mating strategy based on longer term relationships. Overall the results provide partial support for the sexual selection hypothesis for the function of visual art. PMID:22059085

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Multiple sexual signals: Calls over colors for mate attraction in an aposematic, color-diverse poison frog

Directory of Open Access Journals (Sweden)

Corinna Eva Dreher

2014-06-01

Full Text Available Sexual signals indicate species identity and mate quality, and their importance for mate attraction is largely recognized. Recently, research in animal communication has started to integrate multiple signal modalities and evaluate their interactions. However, mate choice experiments across animal taxa have been limited to laboratory conditions, and assessments of multiple sexual signals under field conditions are still lacking. We take advantage of the divergence in visual and acoustic signals among populations of the Neotropical poison frog Oophaga pumilio to evaluate the importance of male advertisement calls and color patterns in female mate selection. Previous mate choice experiments in this species suggested color-assortative female mate preferences across many populations. Nevertheless, acoustic signals are crucial for sexual selection in frogs, and males of O. pumilio use advertisement calls to attract females. We hypothesize that both advertisement calls and coloration affects female mate selection in O.pumilio. To test this hypothesis we tested 452 receptive females from six populations in Costa Rica and Panama in their natural home ranges for preferences regarding local vs. non-local advertisement calls and color patterns. Overall, the calls overrode the effect of coloration, whereby most females preferred local over non-local calls. We found a tendency to prefer brighter (but not necessarily local males in two populations. Furthermore the strength of preferences varied geographically, and thus might be involved in prezygotic isolation among populations. The stronger effect of calls on mate attraction is associated with acoustic divergence between genetic groups in the species, while colour pattern diversity is mostly located within one genetic group, i.e. not linked to large-scale population structure. Finally our data highlights the importance to consider an array of signal modalities in multiple wild populations in studies of

The effect of methyl eugenol exposure on subsequent mating performance of sterile males of the oriental fruit fly, Bactrocera dorsalis

International Nuclear Information System (INIS)

Ji Qing'e; Guo Qingliang; Chen Jiahua

2011-01-01

The effect of methyl eugenol (ME) on the total times of mating, consecutive mating, mating competitiveness, multiple mating, and the incidence of wild female remating were studied in sterile males from a genetic sexing strain of Bactrocera dorsalis (Hendel). Male pupae were irradiated at dose of 100 Gy by 137 Cs at 2 d before emergence and the dose rate was 1.00 Gy/min. Sexually mature 10 day old sterile males were fed ME, while Non-ME-fed sterile males and normal wild males were used as control, and wild females as mating partners. The results showed that some ME-fed sterile males could mate continuously up to nine times, but the total times of consecutive mating and the mean value of continuous mating times were not significant (P > 0.05) compared with the control. The total mating times of ME-fed sterile males was 344.33 ± 12.55 and the mean value was 6.88 ± 0.25, but both have no significant difference compared with the control. The mating success rate of ME-fed and non-ME-fed sterile males mated with wild females were 44.67 ± 2.40% and 22.00 ± 2.31% separately. There were significant differences between them (t = -6.8, P = 0.002). The outcomes were that feeding on ME did not increase the frequency of multiple mating by sterile males, but significantly increased the mating competitiveness of sterile males against wild males. At the same time, sterile males fed ME did not significantly affect the remating of wild females 5 days after the initial mating, but increased the remating frequency of females 10 and 15 days after the initial mating. (authors)

The effect of methyl eugenol exposure on subsequent mating performance of sterile males of the oriental fruit fly, bactrocera dorsalis

International Nuclear Information System (INIS)

Ji Qing'e; Guo Qingliang; Chen Jiaye

2012-01-01

The effect of methyl eugenol (ME) on the total times of mating, consecutive mating, mating competitiveness, multiple mating, and the incidence of wild female remating were studied in sterile males from a genetic sexing strain of Bactrocera dorsalis (Hendel). Male pupae were irradiated at dose of 100 Gy by 137 Cs at 2 d before emergence and the dose rate was 1.00 Gy/min. Sexually mature 10 day old sterile males were fed ME, while Non-ME-fed sterile males and normal wild males were used as control, and wild females as mating partners. The results showed that some ME-fed sterile males could mate continuously up to nine times, but the total times of consecutive mating and the mean value of continuous mating times were not significant (P> 0.05) compared with the control. The total mating times of ME-fed sterile males was 344.33±12.55 and the mean value was 6.88±0.25, but both have no significant difference compared with the control. The mating success rate of ME-fed and non- ME-fed sterile males mated with wild females were (44.67±2.40)% and (22.00±2.31)% separately. There were significant differences between them (t = -6.8, P = 0.002). The outcomes were that feeding on ME did not increase the frequency of multiple mating by sterile males, but significantly increased the mating competitiveness of sterile males against wild males. At the same time, sterile males fed ME did not significantly affect the remating of wild females 5 days after the initial mating, but increased the remating frequency of females 10 and 15 days after the initial mating. (authors)

BATEMANATER: a computer program to estimate and bootstrap mating system variables based on Bateman's principles.

Science.gov (United States)

Jones, Adam G

2015-11-01

Bateman's principles continue to play a major role in the characterization of genetic mating systems in natural populations. The modern manifestations of Bateman's ideas include the opportunity for sexual selection (i.e. I(s) - the variance in relative mating success), the opportunity for selection (i.e. I - the variance in relative reproductive success) and the Bateman gradient (i.e. β(ss) - the slope of the least-squares regression of reproductive success on mating success). These variables serve as the foundation for one convenient approach for the quantification of mating systems. However, their estimation presents at least two challenges, which I address here with a new Windows-based computer software package called BATEMANATER. The first challenge is that confidence intervals for these variables are not easy to calculate. BATEMANATER solves this problem using a bootstrapping approach. The second, more serious, problem is that direct estimates of mating system variables from open populations will typically be biased if some potential progeny or adults are missing from the analysed sample. BATEMANATER addresses this problem using a maximum-likelihood approach to estimate mating system variables from incompletely sampled breeding populations. The current version of BATEMANATER addresses the problem for systems in which progeny can be collected in groups of half- or full-siblings, as would occur when eggs are laid in discrete masses or offspring occur in pregnant females. BATEMANATER has a user-friendly graphical interface and thus represents a new, convenient tool for the characterization and comparison of genetic mating systems. © 2015 John Wiley & Sons Ltd.

The Relationship between Physical Activity and Plasma Glucose Level amongst Ellisras Rural Young Adult Males and Females: Ellisras Longitudinal Study

Directory of Open Access Journals (Sweden)

Moloko Matshipi

2017-02-01

Full Text Available Unhealthy lifestyle characteristics such as low physical activity (PA and high plasma glucose levels (PGLs may lead to the development of type 2 diabetes mellitus in adulthood. The aim of this study was to investigate (i the level of physical activity; (ii the prevalence of pre-diabetes and (iii the relationship between PA and plasma glucose level in a rural Ellisras adult population aged 18 to 28 years. A total of 713 young adults (349 males and 364 females who took part in the Ellisras Longitudinal Study participated in the study. Fasting plasma glucose levels were analysed using Accutrend glucose meters. Physical activity data was collected using a validated questionnaire. Linear regression was used to assess the relationship between PA and pre-diabetes. The prevalence of pre-diabetes was between 45.7% and 50.2% and that of physical inactivity was 67.3% and 71.0% for males and females, respectively. There was no significant (p > 0.05 relationship between PA and pre-diabetes (beta = 1.016; 95% Confidence Interval from 0.352 to 2.777. The health benefits of PA increased with the increasing frequency, duration and intensity of exercise. The prevalence of pre-diabetes was found to be very high in this population. Our results suggest that greater physical activity is associated with low plasma glucose levels.

A cost of sexual attractiveness to high-fitness females.

Directory of Open Access Journals (Sweden)

Tristan A F Long

2009-12-01

Full Text Available Adaptive mate choice by females is an important component of sexual selection in many species. The evolutionary consequences of male mate preferences, however, have received relatively little study, especially in the context of sexual conflict, where males often harm their mates. Here, we describe a new and counterintuitive cost of sexual selection in species with both male mate preference and sexual conflict via antagonistic male persistence: male mate choice for high-fecundity females leads to a diminished rate of adaptive evolution by reducing the advantage to females of expressing beneficial genetic variation. We then use a Drosophila melanogaster model system to experimentally test the key prediction of this theoretical cost: that antagonistic male persistence is directed toward, and harms, intrinsically higher-fitness females more than it does intrinsically lower-fitness females. This asymmetry in male persistence causes the tails of the population's fitness distribution to regress towards the mean, thereby reducing the efficacy of natural selection. We conclude that adaptive male mate choice can lead to an important, yet unappreciated, cost of sex and sexual selection.

Out of Lust or Jealousy: The Effects of Mate-Related Motives on Study-Time Allocation to Faces Varying in Attractiveness

Science.gov (United States)

Li, Fengying; Li, Xinyu; Li, Ping; Jia, Xiaoyu; Chen, Haide; Ji, Haojie

2015-01-01

Although a growing number of empirical studies have revealed that activating mate-related motives might exert a specific set of consequences for human cognition and behaviors, such as attention and memory, little is known about whether mate-related motives affect self-regulated learning. The present study examined the effects of mate-related motives (mate-search and mate-guarding) on study-time allocation to faces varying in attractiveness. In two experiments, participants in mate-related priming conditions (Experiment 1: mate-search; Experiment 2: mate-guarding) or control conditions studied 20 female faces (10 highly attractive, 10 less attractive) during a self-paced study task, and then were given a yes/no face recognition task. The finding of Experiment 1 showed that activating a mate-search motive led the male participants to allocate more time to highly attractive female faces (i.e., perceived potential mates) than to less attractive ones. In Experiment 2, female participants in the mate-guarding priming condition spent more time studying highly attractive female faces (i.e., perceived potential rivals) than less attractive ones, compared to participants in the control condition. These findings illustrate the highly specific consequences of mate-related motives on study-time allocation, and highlight the value of exploring human cognition and motivation within evolutionary and self-regulated learning frameworks. PMID:26121131

Out of Lust or Jealousy: The Effects of Mate-Related Motives on Study-Time Allocation to Faces Varying in Attractiveness.

Directory of Open Access Journals (Sweden)

Weijian Li

Full Text Available Although a growing number of empirical studies have revealed that activating mate-related motives might exert a specific set of consequences for human cognition and behaviors, such as attention and memory, little is known about whether mate-related motives affect self-regulated learning. The present study examined the effects of mate-related motives (mate-search and mate-guarding on study-time allocation to faces varying in attractiveness. In two experiments, participants in mate-related priming conditions (Experiment 1: mate-search; Experiment 2: mate-guarding or control conditions studied 20 female faces (10 highly attractive, 10 less attractive during a self-paced study task, and then were given a yes/no face recognition task. The finding of Experiment 1 showed that activating a mate-search motive led the male participants to allocate more time to highly attractive female faces (i.e., perceived potential mates than to less attractive ones. In Experiment 2, female participants in the mate-guarding priming condition spent more time studying highly attractive female faces (i.e., perceived potential rivals than less attractive ones, compared to participants in the control condition. These findings illustrate the highly specific consequences of mate-related motives on study-time allocation, and highlight the value of exploring human cognition and motivation within evolutionary and self-regulated learning frameworks.

Mating choice of Ceratitis capitata (Wiedemann) (Diptera: Tephritidae): influence of male ageing on mating success; Escolha de parceiro para acasalamento em Ceratitis capitata (Wiedemann)(Diptera: Tephritidae): influencia do envelhecimento dos machos no sucesso de copula

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Silva Neto, Alberto M. da; Dias, Vanessa S.; Joachim-Bravo, Iara S. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Biologia. Dept. de Biologia Geral], e-mail: bio.alberto@gmail.com, e-mail: vanessasidias@hotmail.com, e-mail: ibravo@ufba.br

2009-09-15

The objective of this study was to evaluate the effect of male ageing on male pheromone release and mating success of Ceratitis capitata (Wiedemann). The effects of male ageing on mating were evaluated on fi ve and 21 d-old males by assessing their mating success (males chosen by a female for copulation) and the amount of males releasing the sex pheromone. The mating success was evaluated by using several ratios of young to older males by increasing the number of older males:young males from 1:1 to 5:1. The mating success of the 1:1 ratio was also evaluated in fi eld cages. The evaluation of the mating success (in the 1:1 ratio) showed a clear preference of the females for young males. Sex pheromone emission was much more common on young than older males. Even in cases were older males were more abundant (ratios 2:1 and 3:1), females still chose the young males. However, females could not distinguish young from older males in ratios of 4:1 or 5:1. Our data indicate that the ageing of C. capitata males has a considerable negative effect on their reproductive success, especially if they are found in a proportion any lower than 3:1. (author)

Mating duration and sperm precedence in the spider Linyphia triangularis

DEFF Research Database (Denmark)

Weldingh, Ditte L.; Toft, Søren; Larsen, Ole Næsbye

2011-01-01

, especially the males, are able to influence the outcome of mating for their own benefit. We studied the linyphiid spider Linyphia triangularis in which mating follows a strict sequence during which the male inducts two droplets of sperm and transfers them to the female. We performed sperm competition...

The impact of Wolbachia, male age and mating history on cytoplasmic incompatibility and sperm transfer in Drosophila simulans.

Science.gov (United States)

Awrahman, Z A; Champion de Crespigny, F; Wedell, N

2014-01-01

Most insects harbour a variety of maternally inherited endosymbionts, the most widespread being Wolbachia pipientis that commonly induce cytoplasmic incompatibility (CI) and reduced hatching success in crosses between infected males and uninfected females. High temperature and increasing male age are known to reduce the level of CI in a variety of insects. In Drosophila simulans, infected males have been shown to mate at a higher rate than uninfected males. By examining the impact of mating rate independent of age, this study investigates whether a high mating rate confers an advantage to infected males through restoring their compatibility with uninfected females over and above the effect of age. The impact of Wolbachia infection, male mating rate and age on the number of sperm transferred to females during copulation and how it relates to CI expression was also assessed. As predicted, we found that reproductive compatibility was restored faster in males that mate at higher rate than that of low mating and virgin males, and that the effect of mating history was over and above the effect of male age. Nonvirgin infected males transferred fewer sperm than uninfected males during copulation, and mating at a high rate resulted in the transfer of fewer sperm per mating irrespective of infection status. These results indicate that the advantage to infected males of mating at a high rate is through restoration of reproductive compatibility with uninfected females, whereas uninfected males appear to trade off the number of sperm transferred per mating with female encounter rate and success in sperm competition. This study highlights the importance Wolbachia may play in sexual selection by affecting male reproductive strategies. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

Mating competitiveness of sterile male Anopheles coluzzii in large cages.

Science.gov (United States)

Maïga, Hamidou; Damiens, David; Niang, Abdoulaye; Sawadogo, Simon P; Fatherhaman, Omnia; Lees, Rosemary S; Roux, Olivier; Dabiré, Roch K; Ouédraogo, Georges A; Tripet, Fréderic; Diabaté, Abdoulaye; Gilles, Jeremie R L

2014-11-26

Understanding the factors that account for male mating competitiveness is critical to the development of the sterile insect technique (SIT). Here, the effects of partial sterilization with 90 Gy of radiation on sexual competitiveness of Anopheles coluzzii allowed to mate in different ratios of sterile to untreated males have been assessed. Moreover, competitiveness was compared between males allowed one versus two days of contact with females. Sterile and untreated males four to six days of age were released in large cages (~1.75 sq m) with females of similar age at the following ratios of sterile males: untreated males: untreated virgin females: 100:100:100, 300:100:100, 500:100:100 (three replicates of each) and left for two days. Competitiveness was determined by assessing the egg hatch rate and the insemination rate, determined by dissecting recaptured females. An additional experiment was conducted with a ratio of 500:100:100 and a mating period of either one or two days. Two controls of 0:100:100 (untreated control) and 100:0:100 (sterile control) were used in each experiment. When males and females consort for two days with different ratios, a significant difference in insemination rate was observed between ratio treatments. The competitiveness index (C) of sterile males compared to controls was 0.53. The number of days of exposure to mates significantly increased the insemination rate, as did the increased number of males present in the untreated: sterile male ratio treatments, but the number of days of exposure did not have any effect on the hatch rate. The comparability of the hatch rates between experiments suggest that An. coluzzii mating competitiveness experiments in large cages could be run for one instead of two days, shortening the required length of the experiment. Sterilized males were half as competitive as untreated males, but an effective release ratio of at least five sterile for one untreated male has the potential to impact the fertility of

A preference for a sexual signal keeps females safe.

Directory of Open Access Journals (Sweden)

Tae Won Kim

Full Text Available Predation is generally thought to constrain sexual selection by female choice and limit the evolution of conspicuous sexual signals. Under high predation risk, females usually become less choosy, because they reduce their exposure to their predators by reducing the extent of their mate searching. However, predation need not weaken sexual selection if, under high predation risk, females exhibit stronger preferences for males that use conspicuous signals that help females avoid their predators. We tested this prediction in the fiddler crab Uca terpsichores by increasing females' perceived predation risk from crab-eating birds and measuring the attractiveness of a courtship signal that females use to find mates. The sexual signal is an arching mound of sand that males build at the openings of their burrows to which they attract females for mating. We found that the greater the risk, the more attractive were males with those structures. The benefits of mate preferences for sexual signals are usually thought to be linked to males' reproductive contributions to females or their young. Our study provides the first evidence that a female preference for a sexual signal can yield direct survival benefits by keeping females safe as they search for mates.

The role of pheromone receptors for communication and mating in Hypocrea jecorina (Trichoderma reesei)

Science.gov (United States)

Seibel, Christian; Tisch, Doris; Kubicek, Christian P.; Schmoll, Monika

2012-01-01

Discovery of sexual development in the ascomycete Trichoderma reesei (Hypocrea jecorina) as well as detection of a novel class of peptide pheromone precursors in this fungus indicates promising insights into its physiology and lifestyle. Here we investigated the role of the two pheromone receptors HPR1 and HPR2 in the H. jecorina pheromone-system. We found that these pheromone receptors show an unexpectedly high genetic variability among H. jecorina strains. HPR1 and HPR2 confer female fertility in their cognate mating types (MAT1-1 or MAT1-2, respectively) and mediate induction of fruiting body development. One compatible pheromone precursor–pheromone receptor pair (hpr1–hpp1 or hpr2–ppg1) in mating partners was sufficient for sexual development. Additionally, pheromone receptors were essential for ascospore development, hence indicating their involvement in post-fertilisation events. Neither pheromone precursor genes nor pheromone receptor genes of H. jecorina were transcribed in a strictly mating type dependent manner, but showed enhanced expression levels in the cognate mating type. In the presence of a mating partner under conditions favoring sexual development, transcript levels of pheromone precursors were significantly increased, while those of pheromone receptor genes do not show this trend. In the female sterile T. reesei strain QM6a, transcriptional responses of pheromone precursor and pheromone receptor genes to a mating partner were clearly altered compared to the female fertile wild-type strain CBS999.97. Consequently, a delayed and inappropriate response to the mating partner may be one aspect causing female sterility in QM6a. PMID:22884620

Floral to green: mating switches moth olfactory coding and preference.

Science.gov (United States)

Saveer, Ahmed M; Kromann, Sophie H; Birgersson, Göran; Bengtsson, Marie; Lindblom, Tobias; Balkenius, Anna; Hansson, Bill S; Witzgall, Peter; Becher, Paul G; Ignell, Rickard

2012-06-22

Mating induces profound physiological changes in a wide range of insects, leading to behavioural adjustments to match the internal state of the animal. Here, we show for the first time, to our knowledge, that a noctuid moth switches its olfactory response from food to egg-laying cues following mating. Unmated females of the cotton leafworm (Spodoptera littoralis) are strongly attracted to lilac flowers (Syringa vulgaris). After mating, attraction to floral odour is abolished and the females fly instead to green-leaf odour of the larval host plant cotton, Gossypium hirsutum. This behavioural switch is owing to a marked change in the olfactory representation of floral and green odours in the primary olfactory centre, the antennal lobe (AL). Calcium imaging, using authentic and synthetic odours, shows that the ensemble of AL glomeruli dedicated to either lilac or cotton odour is selectively up- and downregulated in response to mating. A clear-cut behavioural modulation as a function of mating is a useful substrate for studies of the neural mechanisms underlying behavioural decisions. Modulation of odour-driven behaviour through concerted regulation of odour maps contributes to our understanding of state-dependent choice and host shifts in insect herbivores.

Reproductive performance of gilts according to growth rate and backfat thickness at mating.

Science.gov (United States)

Amaral Filha, W S; Bernardi, M L; Wentz, I; Bortolozzo, F P

2010-08-01

The study evaluated the influence of growth rate (GR) and backfat thickness (BF), at first mating of gilts, on the reproductive performance until the first farrowing and on the variation in birth weight of piglets. Gilts were categorized into three groups according to GR from birth until the first mating: GRI (600-700 g/d; n = 345), GRII (701-770 g/d; n = 710) and GRIII (771-870 g/d; n = 366). Analyses were also performed considering three groups formed according to BF (mm) at mating: BFI (10-15 mm; n = 405); BFII (16-17 mm; n = 649)and BFIII (18-23 mm; n = 367). There were no differences in farrowing rate and return to estrus rate among BF or GR groups (P > 0.05). GRII and GRIII females had larger litter size compared to GRI gilts (P GRI and GRII females. Moreover GRIII females had more piglets (P GRI females. More total born and born alive piglets were observed in BFII compared with BFI females (P 0.05). These results show that there is no advantage, in terms of farrowing rate and number of born alive, in performing the first mating of gilts with GR> 770 g/d and BF > 17 mm.

Terminal Investment Strategies and Male Mate choice: Extreme Tests of Bateman.

Science.gov (United States)

Andrade, Maydianne C B; Kasumovic, Michael M

2005-11-01

Bateman's principle predicts the intensity of sexual selection depends on rates of increase of fecundity with mating success for each sex (Bateman slopes). The sex with the steeper increase (usually males) is under more intense sexual selection and is expected to compete for access to the sex under less intense sexual selection (usually females). Under Bateman and modern refinements of his ideas, differences in parental investment are key to defining Bateman slopes and thus sex roles. Other theories predict sex differences in mating investment, or any expenditures that reduce male potential reproductive rate, can also control sex roles. We focus on sexual behaviour in systems where males have low paternal investment but frequently mate only once in their lifetimes, after which they are often killed by the female. Mating effort (=terminal investment) is high for these males, and many forms of investment theory might predict sex role reversal. We find no qualitative evidence for sex role reversal in a sample of spiders that show this extreme male investment pattern. We also present new data for terminally-investing redback spiders (Latrodectus hasselti). Bateman slopes are relatively steep for male redbacks, and, as predicted by Bateman, there is little evidence for role reversal. Instead, males are competitive and show limited choosiness despite wide variation in female reproductive value. This study supports the proposal that high male mating investment coupled with low parental investment may predispose males to choosiness but will not lead to role reversal. We support the utility of using Bateman slopes to predict sex roles, even in systems with extreme male mating investment.

Pre-Release Consumption of Methyl Eugenol Increases the Mating Competitiveness of Sterile Males of the Oriental Fruit Fly, Bactrocera dorsalis, in Large Field Enclosures

Science.gov (United States)

Shelly, Todd E.; Edu, James; McInnis, Donald

2010-01-01

The sterile insect technique may be implemented to control populations of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), when environmental concerns preclude widespread use of chemical attractants or toxicants. The goal of the present study was to evaluate whether the mating competitiveness of sterile B. dorsalis males could be increased via pre-release feeding on methyl eugenol. Males of the oriental fruit fly are strongly attracted to this plant-borne compound, which they ingest and use in the synthesis of the sex pheromone. Previous studies conducted in the laboratory and small field-cages have shown that males given methyl eugenol produce a more attractive pheromone for females and have a higher mating success rate than males denied methyl eugenol. Here, levels of egg sterility were compared following the release of wild-like flies and either methyl eugenol-fed (treated) or methyl eugenol-deprived (control) sterile males in large field enclosures at four over flooding ratios ranging from 5:1 to 60:1 (sterile: wild-like males). Treated sterile males were fed methyl eugenol for 1–4 h (depending on the over flooding ratio tested) 3 d prior to release. Eggs were dissected from introduced fruits (apples), incubated in the laboratory, and scored for hatch rate. The effect of methyl eugenol was most pronounced at lower over flooding ratios. At the 5:1 and 10:1 over flooding ratios, the level of egg sterility observed for treated, sterile males was significantly greater than that observed for control, sterile males. In addition, the incidence of egg sterility reported for treated sterile males at these lower over flooding ratios was similar to that noted for treated or control sterile males at the 30:1 or 60:1 over flooding ratios. This latter result, in particular, suggests that pre-release feeding on methyl eugenol allows for a reduction in the number of sterile flies that are produced and released, thus increasing the cost

Mating with large males decreases the immune defence of females ...

Indian Academy of Sciences (India)

1Indian Institute of Science Education and Research, BCVK Campus, ... observed results are very likely due to qualitative/quantitative differences in the .... Materials and methods .... that mated with the three types of males within each block.

Effects of temperature on development, mortality, mating and blood feeding behavior of Culiseta incidens (Diptera: Culicidae).

Science.gov (United States)

Su, T; Mulla, M S

2001-06-01

Culiseta incidens Thomson is distributed over most of the western USA and Canada northward to Alaska. Because this mosquito is difficult to colonize, its biology has not been well investigated. We colonized this species in 1998 and studied the effects of temperature on various aspects of its life cycle. The time required for egg melanization and the duration of the egg stage were negatively correlated with temperature. The proportion of fertile egg rafts was temperature-independent. An inverse relationship existed between temperature and egg hatch. Molting and stadium duration after hatching were temperature-dependent, with higher temperature accelerating development and molting. Larvae and pupae experienced lower mortality and higher molting success at lower temperatures. Survivorship of adult mosquitoes fed on sugar solution was inversely proportional to temperature, lethal times for 50% mortality (LT50) were greater at the lower temperature than at the higher temperature. Females survived longer than did males at all test temperatures. Because this species is eurygamous, mating only occurred in large cages. Mating success was also affected by temperature. At the test temperatures, 20 degrees C, 25 degrees C and 30 degrees C, mating started from 3-5 days after emergence and reached a peak on days 13-15 after emergence. Maximum mating rates at 20 degrees C and 25 degrees C were higher than at 30 degrees C. Blood feeding, as indicated by cumulative feeding rates, was affected by cage size, mosquito age and temperature. Mosquitoes in large cages exhibited a much higher feeding rate than in small cages. With age, the cumulative blood feeding rate increased, with the highest rate at 25 degrees C, followed by 20 degrees C and 30 degrees C. At all temperatures tested, most of the blood fed females were mated.

Maternal exposure to di(2-ethylhexyl)phthalate (DEHP) promotes the transgenerational inheritance of adult-onset reproductive dysfunctions through the female germline in mice

International Nuclear Information System (INIS)

Pocar, Paola; Fiandanese, Nadia; Berrini, Anna; Secchi, Camillo; Borromeo, Vitaliano

2017-01-01

Endocrine disruptors (EDs) are compounds known to promote transgenerational inheritance of adult-onset disease in subsequent generations after maternal exposure during fetal gonadal development. This study was designed to establish whether gestational and lactational exposure to the plasticizer di(2-ethylhexyl)phthalate (DEHP) at environmental doses promotes transgenerational effects on reproductive health in female offspring, as adults, over three generations in the mouse. Gestating F0 mouse dams were exposed to 0, 0.05, 5 mg/kg/day DEHP in the diet from gestational day 0.5 until the end of lactation. The incidence of adult-onset disease in reproductive function was recorded in F1, F2 and F3 female offspring. In adult F1 females, DEHP exposure induced reproductive adverse effects with: i) altered ovarian follicular dynamics with reduced primordial follicular reserve and a larger growing pre-antral follicle population, suggesting accelerated follicular recruitment; ii) reduced oocyte quality and embryonic developmental competence; iii) dysregulation of the expression profile of a panel of selected ovarian and pre-implantation embryonic genes. F2 and F3 female offspring displayed the same altered reproductive morphological phenotype and gene expression profiles as F1, thus showing transgenerational transmission of reproductive adverse effects along the female lineage. These findings indicate that in mice exposure to DEHP at doses relevant to human exposure during gonadal sex determination significantly perturbs the reproductive indices of female adult offspring and subsequent generations. Evidence of transgenerational transmission has important implications for the reproductive health and fertility of animals and humans, significantly increasing the potential biohazards of this toxicant. - Highlights: • Maternal exposure to DEHP transgenerationally affects female reproductive health. • DEHP reduced ovarian follicular reserve up to the third generation. • DEHP

Maternal exposure to di(2-ethylhexyl)phthalate (DEHP) promotes the transgenerational inheritance of adult-onset reproductive dysfunctions through the female germline in mice

Energy Technology Data Exchange (ETDEWEB)

Pocar, Paola, E-mail: paola.pocar@unimi.it; Fiandanese, Nadia; Berrini, Anna; Secchi, Camillo; Borromeo, Vitaliano

2017-05-01

Endocrine disruptors (EDs) are compounds known to promote transgenerational inheritance of adult-onset disease in subsequent generations after maternal exposure during fetal gonadal development. This study was designed to establish whether gestational and lactational exposure to the plasticizer di(2-ethylhexyl)phthalate (DEHP) at environmental doses promotes transgenerational effects on reproductive health in female offspring, as adults, over three generations in the mouse. Gestating F0 mouse dams were exposed to 0, 0.05, 5 mg/kg/day DEHP in the diet from gestational day 0.5 until the end of lactation. The incidence of adult-onset disease in reproductive function was recorded in F1, F2 and F3 female offspring. In adult F1 females, DEHP exposure induced reproductive adverse effects with: i) altered ovarian follicular dynamics with reduced primordial follicular reserve and a larger growing pre-antral follicle population, suggesting accelerated follicular recruitment; ii) reduced oocyte quality and embryonic developmental competence; iii) dysregulation of the expression profile of a panel of selected ovarian and pre-implantation embryonic genes. F2 and F3 female offspring displayed the same altered reproductive morphological phenotype and gene expression profiles as F1, thus showing transgenerational transmission of reproductive adverse effects along the female lineage. These findings indicate that in mice exposure to DEHP at doses relevant to human exposure during gonadal sex determination significantly perturbs the reproductive indices of female adult offspring and subsequent generations. Evidence of transgenerational transmission has important implications for the reproductive health and fertility of animals and humans, significantly increasing the potential biohazards of this toxicant. - Highlights: • Maternal exposure to DEHP transgenerationally affects female reproductive health. • DEHP reduced ovarian follicular reserve up to the third generation. • DEHP

RNA interference reveals allatotropin functioning in larvae and adults of Spodoptera frugiperda (Lepidoptera, Noctuidae

Directory of Open Access Journals (Sweden)

I.T.E. Hassanien

2014-05-01

Full Text Available The allatotropin of S. frugiperda (Spofr-AT and its cDNA sequence were characterized 10 years ago, but no functional analyses of the peptide are available. Here we used the RNA interference technique to study the effects of Spofr-AT gene suppression on juvenile hormone (JH and ecdysteroid titers in the hemolymph of larvae, virgin and mated females, and of males. Spofr-AT gene silencing in last instar larvae resulted in an increase in the amount of JH III and 20-hydroxyecdysone in the hemolymph of the animals, corresponding to an acceleration of the prepupal commitment and transformation to the pupa. Mated females showed much higher JH titers in their hemolymph than virgins and laid almost twice the number of eggs. Spofr-AT gene silencing in freshly ecdysed females led to a further increase in egg production and oviposition, but had only a minor effect on the hemoylmph JH titer. Mated females contain considerable amounts of JH I and JH II in their hemoylmph, which are thought to be received from males during copulation. To confirm this hypothesis, we measured the amount of JH homologs in the male accessory reproductive glands (MARG before mating and in the bursa copulatrix (BC of the female after mating. MARG contained high amounts of JH I and JH II, which are transferred to the BC during copulation. One day after mating, JH disappeared from the BC and was then found in the hemolymph of the females. In conclusion, Spofr-AT acts as a true allatotropin in larvae and adults of both sexes of the armyworm.

Strong reproductive skew among males in the multiply mated swordtail Xiphophorus multilineatus (Teleostei).

Science.gov (United States)

Luo, J; Sanetra, M; Schartl, M; Meyer, A

2005-01-01

Male swordtails in the genus Xiphophorus display a conspicuous ventral elongation of the caudal fin, the sword, which arose through sexual selection due to female preference. Females mate regularly and are able to store sperm for at least 6 months. If multiple mating is frequent, this would raise the intriguing question about the role of female choice and male-male competition in shaping the mating system of these fishes. Size-dependent alternate mating strategies occur in Xiphophorus; one such strategy is courtship with a sigmoid display by large dominant males, while the other is gonopodial thrusting, in which small subordinate males sneak copulations. Using microsatellite markers, we observed a frequency of multiple paternity in wild-caught Xiphophorus multilineatus in 28% of families analyzed, but the actual frequency of multiple mating suggested by the correction factor PrDM was 33%. The number of fathers contributing genetically to the brood ranged from one to three. Compared to other species in the family Poeciliidae, both frequency and degree of multiple paternity were low. Paternity was found to be highly skewed, with one male on average contributing more than 70% to the offspring. Hence in this Xiphophorus mating system, typically one male dominates and sneaker males do not appear to be particularly effective. Postcopulatory mechanisms, however, such as sperm competition, are also indicated by our data, using sex-linked phenotypes among the offspring.

Fitness consequences of outcrossing in a social spider with an inbreeding mating system.

Science.gov (United States)

Berger-Tal, Reut; Tuni, Cristina; Lubin, Yael; Smith, Deborah; Bilde, Trine

2014-02-01

Inbreeding mating systems are uncommon because of inbreeding depression. Mating among close relatives can evolve, however, when outcrossing is constrained. Social spiders show obligatory mating among siblings. In combination with a female-biased sex ratio, sib-mating results in small effective populations. In such a system, high genetic homozygosity is expected, and drift may cause population divergence. We tested the effect of outcrossing in the social spider Stegodyphus dumicola. Females were mated to sib-males, to a non-nestmate within the population, or to a male from a distant population, and fitness traits of F1s were compared. We found reduced hatching success of broods from between-population crosses, suggesting the presence of population divergence at a large geographical scale that may result in population incompatibility. However, a lack of a difference in offspring performance between inbred and outbred crosses indicates little genetic variation between populations, and could suggest recent colonization by a common ancestor. This is consistent with population dynamics of frequent colonizations by single sib-mated females of common origin, and extinctions of populations after few generations. Although drift or single mutations can lead to population divergence at a relatively short time scale, it is possible that dynamic population processes homogenize these effects at longer time scales. © 2013 The Author(s). Evolution © 2013 The Society for the Study of Evolution.

Hormonal changes during the mating and conception seasons of wild northern muriquis (Brachyteles arachnoides hypoxanthus).

Science.gov (United States)

Strier, Karen B; Lynch, Jessica W; Ziegler, Toni E

2003-10-01

We investigated hormonal and behavioral changes in wild male and female northern muriquis (Brachyteles arachnoides hypoxanthus) at the Estação Biológica de Caratinga, Minas Gerais, Brazil, during a 6-mo period that encompassed the onset of the 1998-1999 mating and conception seasons. Individual females resumed mating with the resumption of ovarian cycling, which was not synchronized among them or related to their cortisol levels. Females experienced two to seven cycles prior to conceiving, and the first conception occurred 2 mo after the onset of the group's mating season. There were no differences in female cortisol levels across their premating, mating, and conception conditions. Cortisol levels were significantly higher in females than in males prior to the conception season, consistent with the prediction that energy reserves may be associated with breeding readiness in females, but not males, in this species. The sustained elevation in male cortisol occurred after the peak in their sexual activity, which resulted in the first conception of the year. Male cortisol levels were positively correlated between years that were similar in rainfall, but differed in the timing of sexual and reproductive events. The timing of cortisol elevations in males appears to be generally regulated by environmental cues, but is responsive to fine-tuning by social and behavioral cues related to the unpredictable timing of reproductive opportunities within their extended mating season. Copyright 2003 Wiley-Liss, Inc.

Mating System Evolution under Strong Pollen Limitation: Evidence of Disruptive Selection through Male and Female Fitness in Clarkia xantiana.

Science.gov (United States)

Briscoe Runquist, Ryan D; Geber, Monica A; Pickett-Leonard, Michael; Moeller, David A

2017-05-01

Selection on floral traits in hermaphroditic plants is determined by both male and female reproductive success. However, predictions regarding floral trait and mating system evolution are often based solely on female fitness. Selection via male fitness has the potential to affect the outcomes of floral evolution. In this study, we used paternity analysis to assess individual selfing rates and selection on floral traits via male and female fitness in an experimental population of Clarkia xantiana where pollen limitation of seed set was strong. We detected selection through both female and male fitness with reinforcing or noninterfering patterns of selection through the two sex functions. For female fitness, selection favored reduced herkogamy and protandry, traits that promote increased autonomous selfing. For male fitness, selection on petal area was disruptive, with higher trait values conferring greater pollinator attraction and outcross siring success and smaller trait values leading to higher selfed siring success. Combining both female and male fitness, selection on petal area and protandry was disruptive because intermediate phenotypes were less successful as both males and females. Finally, functional relationships among male and female fertility components indicated that selfing resulted in seed discounting and pollen discounting. Under these functional relationships, the evolutionarily stable selfing rate can be intermediate or predominantly selfing or outcrossing, depending on the segregating load of deleterious mutations.

Beyond magic traits: Multimodal mating cues in Heliconius butterflies.

Science.gov (United States)

Mérot, Claire; Frérot, Brigitte; Leppik, Ene; Joron, Mathieu

2015-11-01

Species coexistence involves the evolution of reproductive barriers opposing gene flow. Heliconius butterflies display colorful patterns affecting mate choice and survival through warning signaling and mimicry. These patterns are called "magic traits" for speciation because divergent natural selection may promote mimicry shifts in pattern whose role as mating cue facilitates reproductive isolation. By contrast, between comimetic species, natural selection promotes pattern convergence. We addressed whether visual convergence interferes with reproductive isolation by testing for sexual isolation between two closely related species with similar patterns, H. timareta thelxinoe and H. melpomene amaryllis. Experiments with models confirmed visual attraction based on wing phenotype, leading to indiscriminate approach. Nevertheless, mate choice experiments showed assortative mating. Monitoring male behavior toward live females revealed asymmetry in male preference, H. melpomene males courting both species equally while H. timareta males strongly preferred conspecifics. Experiments with hybrid males suggested an important genetic component for such asymmetry. Behavioral observations support a key role for short-distance cues in determining male choice in H. timareta. Scents extracts from wings and genitalia revealed interspecific divergence in chemical signatures, and hybrid female scent composition was significantly associated with courtship intensity by H. timareta males, providing candidate chemical mating cues involved in sexual isolation. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Mate Preference of Female Blue Tits Varies with Experimental Photoperiod

NARCIS (Netherlands)

Reparaz, L.B.; Van Oers, K.; Naguib, M.; Doutrelant, C.; Visser, M.E.; Caro, S.P.

2014-01-01

Organisms use environmental cues to time their life-cycles and among these cues, photoperiod is the main trigger of reproductive behaviours such as territory defence or song activity. Whether photoperiod is also important for another behaviour closely associated with reproduction, mate choice, is

Mate preference of female blue tits varies with experimental photoperiod

NARCIS (Netherlands)

Reparaz, L.B.; Oers, van K.; Naguib, M.; Doutrelant, C.; Visser, M.E.; Caro, S.P.

2014-01-01

Organisms use environmental cues to time their life-cycles and among these cues, photoperiod is the main trigger of reproductive behaviours such as territory defence or song activity. Whether photoperiod is also important for another behaviour closely associated with reproduction, mate choice, is