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.     

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.     

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.     

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     

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 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.     

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.     

The influence of territoriality and mating system on the evolution of male care: a phylogenetic study on fish

Evolution of male care is still poorly understood. Using phylogenetically matched-pairs comparisons we tested for effects of territoriality and mating system on male care evolution in fish. All origins of male care were found in pair-spawning species (with or without additional males such as sneakers) and none were found in group-spawning species. However, excluding group spawners, male care originated equally often in pair-spawning species with additional males as in strict pair-spawning species. Evolution of male care was also significantly related to territoriality. Yet, most pair-spawning taxa with male care are also territorial, making their relative influence difficult to separate. Furthermore, territoriality also occurs in group-spawning species. Hence, territoriality is not sufficient for male care to evolve. Rather, we argue that it is the combination of territoriality and pair spawning with sequential polygyny that favours the evolution of male care, and we discuss our results in relation to paternity assurance and sexual selection.     

Copulation Is Not a Prerequisite to Male Reception of Eggs in the Golden Egg Bug Phyllomorpha laciniata (Coreidae; Heteroptera)

Females of the golden egg bug, Phyllomorpha laciniata, lay eggs on the backs of conspecifics. Male response to female oviposition attempts is either passive or resistant. Passive males remain still during oviposition, while resistant males move repeatedly and thereby delay or avoid being encumbered. We investigated how previous mating experience affected male acceptance of eggs. Males from two Spanish populations, from Andalusia and Catalonia, were allowed to mate with single females repeatedly. These experimental pairs were then presented with either a single, nonmating male or a pair in copula. We expected mating partners to resist oviposition attempts less strongly than nonmating males but no differences were detected. However, there was a significant difference in behavior exhibited by males from the two populations; males from Catalonia were relatively passive but males from Andalusia routinely resisted encumbrance. Predation pressure and the availability of receptive females may explain the observed differences between the populations.     

What people prefer and what they think they prefer in short- and long-term partners. The effects of the phase of the menstrual cycle,hormonal contraception,pregnancy, and the marital and the parenthood status on partner preferences

The issue with most studies concerned with mate selection preferences in humans is that they rely on declarations and rational actions of experimental subjects, which are affected by their pre-conceived opinions and prejudices. Moreover, current research suggests that subcortical structures and processes, rather than the neocortex, play the principal role in actual partner choice behaviour. Consequently, we have only limited information on how relevant our current knowledge is in relation to real-life human ethology. To address these issues, we surveyed 2718 women and 4073 men between the ages of 16–50 and compared their declared and observed preferences for various properties in short-term and long-term partners. We found differences between what the subjects declared to prefer and what they preferred in reality: for example, men declared that wealth was the second least desirable property out of eleven in short-term partners, but we observed that in reality, they considered wealth the third most important factor after charisma and sense of humour. Similarly, while women declared that dominance and masculinity were desirable properties in short-term partners, in the observational part of the study, they showed little preference for these traits. Furthermore, we investigated the effects of the phase of the menstrual cycle, hormonal contraception, pregnancy, and partnership and parenthood status on these preferences. We found some support for the good parents hypothesis and no support for the good genes and the immunocompetence handicap hypotheses when observed, rather than declared preferences were considered. We also detected that hormonal contraception, and parenthood and partnership status influenced declared preferences in considerable ways, but had only a small, if any, impact on observed preferences. We suggest interpreting the results of studies reliant on declarations and rational actions of experimental subjects with great caution.