Probability of paternity exclusion and the number of loci needed to determine the fathers in a troop of macaques

We calculated the probability of paternity exclusion (P) in 6 troops of rhesus and Japanese macaques housed in open enclosures and 68 wild troops of Japanese, crab-eating, and toque macaques using 33 genetic loci which encoded the blood protein variations detected by electrophoretic techniques. In the open enclosures, especially of rhesus troops, we obtained a fairly high probability of paternity exclusion and succeeded in determining the fathers of offspring. However, we found significant differences between the observed and calculated probabilities in most of the troops. These differences were ascribed to a situation whereby the Hardy-Weinberg equilibrium had not been attained in the troops and/or the numbers of variable loci were too small. In the wild troops of Japanese, crab-eating, and toque macaques, the means ofP were 0.2274 (0.0192–0.5017), 0.4635 (0.1676–0.7151), and 0.7382 (0.6266–0.7954), respectively. We also estimated the number of loci needed to determine the fathers of offspring with a probability of 0.8 assuming that ten males were present in the troop. The estimated number was about 13.5 times, 5 times and 1.8 times the number of loci examined on average in the troops of Japanese, crab-eating and toque macaques, respectively. This means that determination of most of the fathers of offspring in wild troops of these macaques, even of toque macaques which have a rather high probability of paternity exclusion, is difficult so long as we employ only electrophoretic techniques.     

Sperm competition mechanisms,confidence of paternity,and the evolution of paternal care in the golden egg bug (Phyllomorpha laciniata)

Theoretical models predict how paternal effort should vary depending on confidence of paternity and on the trade-offs between present and future reproduction. In this study we examine patterns of sperm precedence in Phyllomorpha laciniata and how confidence of paternity influences the willingness of males to carry eggs. Female golden egg bugs show a flexible pattern of oviposition behavior, which results in some eggs being carried by adults (mainly males) and some being laid on plants, where mortality rates are very high. Adults are more vulnerable to predators when carrying eggs; thus, it has been suggested that males should only accept eggs if there are chances that at least some of the eggs will be their true genetic offspring. We determined the confidence of paternity for naturally occurring individuals and its variation with the time. Paternity of eggs fertilized by the last males to mate with females previously mated in the field has been determined using amplified fragment length polymorphisms (AFLPs). The exclusion probability was 98%, showing that AFLP markers are suitable for paternity assignment. Sperm mixing seems the most likely mechanism of sperm competition, because the last male to copulate with field females sires an average of 43% of the eggs laid during the next five days. More importantly, the proportion of eggs sired does not change significantly during that period. We argue that intermediate levels of paternity can select for paternal care in this system because: (1) benefits of care in terms of offspring survival are very high; (2) males have nothing to gain from decreasing their parental effort in a given reproductive event because sperm mixing makes it difficult for males to reach high paternity levels and males are left with no cues to assess paternity; (3) males cannot chose to care for their offspring exclusively because they can neither discriminate their own eggs, nor can they predict when their own eggs will be produced; and (4) males suffer no loss of further matings with other females when they carry eggs. Thus, our findings do not support the traditional view that paternal investment is expected to arise only in species where confidence of paternity is high. The results suggest that females maximize the chances that several males will accept eggs at different times by promoting a mechanism of sperm mixing that ensures that all males that have copulated with a female have some chance of fathering offspring, that this probability remains constant with time, and that males have no cues as to when their own offspring will be produced.     

The monitoring of the menstrual status of female athletes by salivary steroid determination and ultrasonography

This study was designed to evaluate whether traditional plasma hormone determinations can be adequately replaced by measurements of salivary hormones. Eleven young sportswomen with menstrual irregularities attributed to strenuous physical exercise participated in this study. Mean body weight expressed as a percentage of ideal body weight was 92%, SD 4%. Their mean weekly training distance was 35 km, SD 15. Basal plasma endocrinological measurements revealed a hypo-oestrogenic status (mean plasma oestradiol values: 22 pg.ml-1, SD 8.8), and a deficient luteal phase (mean plasma progesterone: 2.9 ng.ml-1, SD 2.1). Pre-exercise salivary sex steroids were low. Salivary progesterone levels were 39.3 pg.ml-1, SD 9.5 (normal ranges in saliva: 25-60 pg.ml-1), salivary oestrone (E1) was 12.2 pg.ml-1, SD 2.3 (normal ranges in saliva: 7.5-25 pg.ml-1), and salivary oestradiol (E2) less than 1.9 pg.ml-1, SD 1.1 (normally 1.0-10.0 pg.ml-1). After a 21-km run, all salivary steroids appeared to increase. Mean salivary testosterone levels increased by 15.2% and salivary progesterone by 14.8%. Mean salivary oestrogens also increased (E1: +13.9%; E2: +21.1%). These findings confirm the results of earlier studies which found higher post-exercise plasma sex steroid levels. Since salivary measurements are believed to reflect non-protein-bound, thus free steroid levels, the results obtained by these techniques may provide a more realistic picture of the hormonal effects of physical exercise. In future, more accurate, cost-effective and easier techniques for salivary measurements may offer additional advantages.     

Physiological variation in estradiol and brain function: a functional magnetic resonance imaging study of verbal memory across the follicular phase of the menstrual cycle

Women frequently complain of memory problems at times in their reproductive lives that are associated with changes in estrogen concentration (e.g. around menopause and childbirth). Further, behavioural studies suggest that memory performance may fluctuate across the menstrual cycle. For example, performance on verbal tasks has been reported to be greatest during phases associated with high estrogen concentrations whereas the opposite has been reported with visuo-spatial tasks. The biological basis of these reported effects remains poorly understood. However, brain imaging studies into the effects of estrogen therapy in postmenopausal women suggest that estrogen modulates the metabolism and function of brain regions sub-serving memory. Furthermore, we have recently reported that acute suppression of ovarian function in young women (with a Gonadotropin Hormone Releasing Hormone agonist) is associated with decreased activation in left prefrontal cortex, particularly the left inferior frontal gyrus (LIFG), during successful verbal memory encoding. We therefore investigated whether physiological variation in plasma estradiol concentration is associated with differences in activity of the LIFG during successful verbal encoding. We hypothesised that higher plasma concentrations of estradiol would be associated with increased brain activity at the LIFG and improved recall performance. Although we did not find a significant relationship between plasma estradiol concentration and verbal recall performance, we report a positive correlation between brain function and estradiol concentration at the LIFG.     

Cuckoldry and the stability of biparental care

In socially monogamous species, females may engage in extra-pair fertilizations to gain direct or indirect benefits not provided by the social mate, with the potential risk of a reduction in the social mate’s paternal effort. I present an ESS model of cuckoldry frequencies, which considers both facultative and nonfacultative male responses to losses in paternity. Two possible equilibria exist: stable social monogamy with varying degrees of extra-pair paternity, and polygamy with little or no male care. Monogamy with limited cuckoldry can be stable only if the initial cuckoldry frequency is low, intrinsic cuckoldry benefits are not high, males can reasonably accurately detect cuckoldry, and female compensation for losses in male care is incomplete. Deviations from these assumptions lead to stronger mate acquisition in males at the expense of paternal care, and eventually to runaway evolution towards polygamy. Average female fitness is reduced in the runaway, although it is initiated by females maximizing the survival of offspring – a potential “tragedy of the commons” in breeding systems.     

Quantitative histomorphometric analysis of gonadal steroid receptor distribution in the normal human endometrium through the menstrual cycle

The aim of this study was to test the hypothesis that the distribution of oestrogen receptor beta (ER) and androgen receptor (AR) are related to cell proliferation or correlated with the expression of progesterone receptor (PR) or oestrogen receptor alpha (ER) in the normal human endometrium. Immunohistochemical distribution of immunoreactive ER in well-characterised menstrual cycle biopsy samples was lowest in proliferative endometrial glands, highest in early secretory phase glands and maintained at ~20% throughout the rest of the menstrual cycle and was closely correlated with stromal AR and stromal ER expression. Stromal ER was not significantly altered until the menstrual phase of the cycle and was not correlated with the expression of any other antigen in the stroma or endometrial glands except stromal AR. By contrast, glandular AR immunoreactivity was below 5% early in the cycle, increased during the secretory phase and showed strong expression just before menstruation. PR and Ki-67 expression showed strong positive correlations, indicating that PR may be a potent regulator of endometrial proliferation. These data suggest that glandular ER expression is closely associated with a functional secretory role whereas glandular ER and PR are associated with proliferation; glandular AR expression may be the switch required for menstruation.     

Changes in the extracellular matrix of the normal human breast during the menstrual cycle

Summary The normal human mammary gland undergoes a well defined sequence of histological changes in both epithelial and stromal compartments during the menstrual cycle. Studies in vitro have suggested that the extracellular matrix surrounding the individual cells plays a central role in modulating a wide variety of cellular events, including proliferation, differentiation and gene expression. We therefore investigated the distribution of a number of extracellular matrix molecules in the normal breast during the menstrual cycle. By use of indirect immunofluorescence, with specific antibodies, we demonstrated that laminin, heparan sulphate proteoglycan, type IV collagen, type V collagen, chondroitin sulphate and fibronectin undergo changes in distribution during the menstrual cycle, whereas collagen types I, III, VI and VII remain unchanged. These changes were most marked in the basement membrane, sub-basement membrane zone and delimiting layer of fibroblasts surrounding the ductules where basement membrane markers such as laminin, heparan sulphate proteoglycan, and type IV and V collagens appear greatly reduced during the mid-cycle period (days 8 to 22). These results suggest that some extracellular matrix molecules may act as medittors in the hormonal control of the mammary gland, whereas others may have a predominantly structural role.     

Coevolution of female fidelity and male help in populations with alternative reproductive tactics

In socially monogamous species, pair-bonded males often continue to provide care to all offspring in their nests despite some degree of paternity loss due to female extra-pair copulation. Previous theoretical models suggested that females can use their within-pair offspring as ‘hostages'' to blackmail their social mates, so that they continue to provide care to the brood at low levels of cuckoldry. These models, however, rely on the assumption of sufficiently accurate male detection of cuckoldry and the reduction of parental effort in case of suspicion. Therefore, they cannot explain the abundant cases where cuckolded males continue to provide extensive care to the brood. Here we use an analytical population genetics model and an individual-based simulation model to explore the coevolution of female fidelity and male help in populations with two genetically determined alternative reproductive tactics (ARTs): sneakers that achieve paternity solely via extra-pair copulations and bourgeois that form a mating pair and spend some efforts in brood care. We show that when the efficiency of mate guarding is intermediate, the bourgeois males can evolve to ‘specialize'' in providing care by spending more than 90% of time in helping their females while guarding them as much as possible, despite frequent cuckoldry by the sneakers. We also show that when sneakers have tactic-specific adaptations and thus are more competitive than the bourgeois in gaining extra-pair fertilizations, the frequency of sneakers and the degrees of female fidelity and male help can fluctuate in evolutionary cycles. Our theoretical predictions highlight the need for further empirical tests in species with ARTs.     

The effect of the menstrual cycle on collagen metabolism,growth hormones and strength in young physically active women

This study aimed to investigate the effect of the menstrual cycle on strength, functioning of the GH/IGF-1 axis and collagen metabolism in physically active women. Twenty-four physically active and eumenorrheic women volunteered to participate in the study (body mass 60.3 ± 9.18 kg, age 21.8 ± 0.92 years). Blood samples were obtained between the 5th and 8th days (the follicular phase) and between the 19th and 22th days (the luteal phase) of the menstrual cycle to determine sex steroid concentrations (follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), oestradiol (E2) and progesterone (P)). Also insulin-like growth factor 1 (IGF-1) and collagen metabolism markers (synthesis (PICP) and breakdown (ICTP)) and maximum voluntary contraction (MVC) were measured. MVC was higher in the luteal phase 164.1 ± 34.77 [N m] (F(1.23) = 4.59; p = 0.043). The recorded collagen synthesis marker (PICP = 296.4 ± 35.61 [ng/ml]) was at the upper level of the reference range (30–300), with an insignificant decrease in the luteal phase (Z = 1.612; p = 0.107) and a significant increase in oestradiol concentration (Z = 4.286; p = 0.0001). The marker of collagen breakdown (ICTP = 4.16 ± 0.68 [μg/l]) was reduced by 6.8% in the same phase (Z = 1.764; p = 0.137). The variability of physical abilities (MVC) during the menstrual cycle showed that menstrual status should be taken into account in determination of the training loads. Increasing the load in the luteal phase seems to be favoured by a beneficial change in collagen metabolism (lower synthesis decrease, lower breakdown increase) observed in physically active women.     

Commitment to relationships and preferences for femininity and apparent health in faces are strongest on days of the menstrual cycle when progesterone level is high

Previous studies of changes in women's behavior during the menstrual cycle have offered insight into the motivations underpinning women's preferences for social cues associated with possible direct benefits (e.g., investment, low risk of infection) and indirect benefits (e.g., offspring viability). Here we sought to extend this work by testing for systematic variation in women's preferences for male and female faces and in their attitudes to their romantic relationship during the menstrual cycle. In Study 1, we found partnered women's reported commitment to their romantic relationship and preferences for femininity in male and female faces were strongest on days of the menstrual cycle when progesterone levels are increased (and fertility is low). Happiness in relationships did not change across the cycle. In Study 2, we found that the effect of cycle phase on women's preference for feminine faces was independent of increased attraction to apparent health in faces during the luteal phase. Collectively, these findings are further evidence that women's preferences for social cues associated with possible direct benefits and commitment to relationships are strongest during conditions characterized by raised progesterone level, while attraction to men displaying cues associated with possible indirect benefits is strongest when women are most fertile.     

The effect of female proximity and social interaction on the menstrual cycle of crab-eating monkeys (Macaca fascicularis)

Twelve adult female crab-eating monkeys (Macaca fascicularis) were placed in six pairs of adjacent cages, allowing physical contact between members of these experimental pairs. Twelve additional females remained singly caged (no physical contact allowed) and served as six control “pairs.” In both experimental and control pairs, one member had a history of regular menstrual cycles, whereas the other tended to have cycles that were unusually long and/or irregular. Over a six-month period, menses and amount of vaginal secretion were recorded daily for all subjects, and the behavior of experimental pairs was sampled three times per week. During the course of the study, the irregular experimental subjects began to exhibit menstrual cycles of near normal length although there was no apparent trend to synchronize cycles. Irregular controls continued to show cycles that were abnormally long. Vaginal secretions tended to increase in all regularly cycling animals during days 9–15 (peak day 11) or reverse days 21–16 of the cycle, consistent with the estimated time of ovulation. Analysis of behavior indicated that irregularly cycling subjects inspected the genitalia of their regularly cycling cagemates at a significantly higher frequency than the converse (F=12.61,p<.005), particularly during the follicular phase (F=3.39,p<.07). These results suggest that close physical contact may serve to transmit chemical and/or hormonal cues that can normalize the menstrual cycle of crab-eating monkeys.     

Behavioral changes across the menstrual cycle in isosexual groups of bonnet macaques (Macaca radiata)

Behavioral changes were systematically recorded across menstrual cycles over a six-month period in two laboratory-housed isosexual triads ofMacaca radiata (bonnet macaque). The purpose of this study was to determine whether females of this species demonstrate premenstrual behavioral changes as reported for humans, or heightened levels of aggression during the first half of their cycle as reported in some species of Old World monkeys. A total of 34 menstrual cycles were divided into five segments including two follicular, one periovulatory, and two luteal phases. The mean frequencies of behaviors were analyzed according to phase, rank, and time since triad formation, for a total of 34 menstrual cycles. There was no evidence of an increase in spatial separation during the premenstrual phase or during any other phase of the menstrual cycle. Although contact aggression did not show an increase during the early follicular half of the cycle (phases 1 and 2) or during the phase of the cycle immediately preceding menses (phase 5), contact aggression did show two peaks: one in the early-mid luteal half of the cycle (phase 4) and a peak in the mid-late follicular (phase 2). The non-aggressive hierarchical behaviors did not follow the same pattern as contact aggression. Instead the distribution of these behaviors showed a pattern similar to that of estrogen levels across the cycle. Subjects’ location in pen also varied significantly according to cycle phase: subjects spent more time on perches during the premenstrual phase and more time on the pen floor during the periovulatory phase. The increase in contact aggressive behaviors during the early-mid follicular phase and the mid-late luteal phase does not suggest a simple hormonal correlate as these two phases are characterized by high levels of estrogen and progesterone, respectively. However, the distribution of non-aggressive hierarchical behaviors suggest that this category of agonistic interaction may be related to mating competition among females of this species. Results are discussed with reference to the social behavior and promiscuous mating strategy ofM. radiata. The findings in this present study are compared with previous studies utilizing other species of Old World monkeys. Differences in study design and group composition are considered as factors effecting discrepant results both within and between species.     

Singing strategies among male Black-browed Reed Warblers Acrocephalus bistrigiceps during the post-fertile period of their mates

Bird song is critical to mate attraction. Because singing involves fitness costs, males that sing vigorous and complex songs are thought to be of high quality. Males of the Black-browed Reed Warbler Acrocephalus bistrigiceps sang actively when they were solitary, but stopped singing as soon as they had attracted a female. Males exhibited two distinct patterns of singing behaviour after the fertile period of their mates: some resumed singing, whereas others did not. Males that resumed singing acquired secondary females more frequently than those that did not sing, suggesting that resuming males seek polygynous mating. The occurrence of extra-pair fertilization was rare (6.4%) in the study population, and extra-pair young were sired by both resuming and non-resuming males. There is no strong evidence that non-resuming males compensate for their disadvantage in social mate acquisition by extra-pair paternity. Resuming males arrived at the breeding ground earlier, suggesting that they were high-quality males.     

Psychopathic personality traits and cortisol response to stress: The role of sex, type of stressor, and menstrual phase

Previous research indicates that psychopathic personality traits are associated with lower cortisol secretion in response to stress in men but not in women. The current study explored whether prior null results for women were related to the latency of the cortisol stress response to two different types of stressors. Additionally, accuracy of self-reported menstrual phase was explored via salivary progesterone levels. A mixed-sex sample of 145 participants characterized by high (36 men, 37 women) and low (34 men, 38 women) scores on a screening measure of psychopathic personality traits were randomly assigned to either a performance-based stressor task or a social rejection stressor task. Salivary hormone samples were taken just prior to task onset (baseline) and at 0, 20, 40, and 60 min post-stressor. Results indicated that both men and women characterized by psychopathic personality traits exhibited lower stress-induced cortisol levels to the performance-based task in comparison with controls at 20 min post-stressor. The social rejection task produced a cortisol response 20 min post-stressor in the male controls only. Removal of women with low progesterone from the analyses strengthened the psychopathy group differences. Results could suggest that deficient cortisol production in response to stress might be another important neurobiological feature associated with psychopathic traits, and that biological verification of menstrual phase is an important aspect to obtaining accurate cortisol results in women.     

The reporductive cycle and population dynamics: The case of the Banges Valley (Valais,Switzerland) in the XIXth century

By discussing the concept of population reproduction from the points of view of different disciplines, we propose here a reflection on the foundation of population studies, i.e. the definition of the population studied and the mechanisms of its dynamics. Our considerations are based on the example of the Bagnes valley in the 19th century, putting it into perspective with data we have gathered in two other traditional populations. In the first part of the paper, we explore the different types of constraints and facilitators which act on the effective descent of individuals. The population reproduction is thus considered in terms of numerical replacement, that is to say the meaning which demography usually gives to it. The second part focuses on the factors of the renewal of the group, signification attributed to population reproduction in evolutionary sciences. The definition of the boundaries of the population and their tendencies become central, as well as the criteria following which individuals belong to the group. Translation from the French by Graham Grayston     

The function of mate guarding in a field cricket (Orthoptera: Gryllidae;Teleogryllus natalensis otte and cade)

Three hypotheses relating to the function of postcopulatory mate guarding were tested for the cricketTeleogryllus natalensis. The hypothesis that guarding allows the male to remain with the female for repeated matings was rejected. This was because the mean intercopulatory interval for maleT. natalensis was found to be nearly twice as long as the mean duration of guarding. Nor do the results provide evidence to support the hypothesis that guarding functions to prevent copulation attempts by rival males (the rival exclusion hypothesis): the presence of a rival male was found to have no significant effect on the duration of spermatophore attachment for either guarded or unguarded females. The results do, however, support a third hypothesis, namely, that guarding functions to prevent the female from removing the spermatophore ampulla before complete sperm transfer. As predicted by this hypothesis, the presence of a guarding male was found to have a significant positive effect on the duration of spermatophore attachment. Further support for this hypothesis was provided by the fact that there was a significant positive correlation between the duration of mate guarding and the duration of spermatophore attachment.     

社会性单配制鸟类婚外父权的发生和影响因素

一雌一雄单配制鸟类中,雌性个体与配偶外雄性发生交配的行为称为婚外交配,继而导致了婚外受精产生婚外子代的现象称为产生了婚外父权。婚外父权广泛存在于鸟类中,针对其发生和影响因素已经成为了鸟类行为生态学研究的热点。本文收集了近十年社会性单配制鸟类婚外父权方面的研究文献,从婚外父权的发生及其影响因素两个方面综述了单配制鸟类婚外父权的研究进展。婚外父权发生原因的探讨主要包括：1、从两性的角度探讨雌雄两性在婚外行为中不同的进化繁殖策略。雄性策略旨在增加自身的繁殖输出;有关雌性策略则提出了确保受精假说、食物供给假说、遗传利益假说等,但目前尚存争议;2、在遗传利益假说中较常见的又分为3个假说：“优秀基因”假说、“遗传相容性”假说和“遗传多样性”假说,该三种假说是针对雌性从遗传方面获得的利益而提出的,不断有报道指出雌性配偶选择会被潜在的雄性遗传特性所影响;3、非遗传利益——母系效应影响婚外父权的进化。一些研究指出遗传质量参数,如体重、身体大小、存活率和免疫应答等方面可能会存在母系效应。婚外父权发生的影响因素这里主要指环境因素,包括繁殖同步性、繁殖密度、栖息地环境、产卵及孵化时机等。由于物种不同,受到环境压力不同,导致婚外父权发生率千差万别。最后本文针对未来的研究方向做出了展望。尽管近十年的研究进一步解释了鸟类婚外父权现象,但是该领域仍然存在并且产生了许多新的未解决的问题,而相关实验操作和理论的完善是深入探讨这些问题的关键。     

The relation between mate value, entitlement, physical aggression, size and strength among a sample of young Indian men

This study extends previous ones showing a link between direct aggression and size and strength among young men, which were informed by the evolutionary concept of resource holding power (RHP), using measures of size, strength, flexed bicep circumference and hand grip strength among a sample of young men from the Indian state of Mizoram. The study also examined the relation of these variables to reactive and proactive aggression, to entitlement to resources (related to the threatened egotism theory of aggression) and mate value (central to a modular theory of self-esteem and more broadly to sexual selection). The findings showed only a weak association between size and strength and direct aggression, which was also significantly correlated with entitlement and mate value, as predicted. Mate value also showed some association with size and strength. Reactive but not proactive aggression was linked with entitlement, but neither was associated with size or strength. In a regression analysis, controlling for age, mate value was the strongest predictor of direct aggression, but both weight (highly correlated with strength) and entitlement were marginally significant predictors independent of mate value. The findings provide support for the view that young males who view themselves as more attractive to women are more aggressive, independently of the impact on aggressiveness of RHP or entitlement to resources.