Early stress predicts age at menarche and first birth,adult attachment,and expected lifespan

Life history theory suggests that in risky and uncertain environments the optimal reproductive strategy is to reproduce early in order to maximize the probability of leaving any descendants at all. The fact that early menarche facilitates early reproduction provides an adaptationist rationale for our first two hypotheses: that women who experience more risky and uncertain environments early in life would have (1) earlier menarche and (2) earlier first births than women who experience less stress at an early age. Attachment theory and research provide the rationale for our second two hypotheses: that the subjective early experience of risky and uncertain environments (insecurity) is (3) part of an evolved mechanism for entraining alternative reproductive strategies contingent on environmental risk and uncertainty and (4) reflected in expected lifespan. Evidence from our pilot study of 100 women attending antenatal clinics at a large metropolitan hospital is consistent with all four hypotheses: Women reporting more troubled family relations early in life had earlier menarche, earlier first birth, were more likely to identify with insecure adult attachment styles, and expected shorter lifespans. Multivariate analyses show that early stress directly affected age at menarche and first birth, affected adult attachment in interaction with expected lifespan, but had no effect on expected lifespan, where its original effect was taken over by interactions between age at menarche and adult attachment as well as age at first birth and adult attachment. We discuss our results in terms of the need to combine evolutionary and developmental perspectives and the relation between early stress in general and father absence in particular. This work was supported by The University of Melbourne Department of Obstetrics and Gynaecology. James S. Chisholm is Professor in the School of Anatomy and Human Biology at the University of Western Australia. He is an anthropologist whose interests lie in the fields of human behavioral biology, evolutionary ecology, life history theory, and parental investment theory, where he focuses on infant social-emotional development, the development of reproductive strategies, and the integration of evolutionary, developmental, and cultural psychology and public health. Julie A. Quinlivan is Associate Professor in Obstetrics and Gynaecology at the University of Melbourne and Head of the Maternity Care Program at the Royal Women’s Hospital, Melbourne. Her interests are teenage pregnancy, domestic violence, child abuse prevention, and high-risk pregnancy. Rodney W. Petersen is Senior Lecturer in Obstetrics and Gynaecology at the University of Melbourne and Senior Consultant in Obstetrics and Gynaecology at the Royal Women’s Hospital and Sunshine Hospital in Melbourne. His interests are in psychosocial aspects of women’s health and cancer. David A. Coall is a Ph.D. student in the School of Anatomy and Human Biology at the University of Western Australia. His main interest lies in the application of evolutionary theory within an epidemiological framework. He is currently working on the synthesis of life history theory, parental investment theory, and parent-offspring conflict theory in exploring factors that influence variation in human birth weight and placental weight.     

中国兔猴的单一物种及其两性差别

观察到以前描述的中国兔猴不同种的特征在禄丰的全部中国兔猴标本中交叉地存在、并通过连续的中间表现型而衔接,本文建议石灰坝中国兔猴是厚齿中国兔候的同种异名,因而前一名称应予取消。以犬齿和下第四前臼齿为材料研究了中国兔猴的两性差别。本文使用双变量分布确定两性重叠分布的测量性状的性别差异取得较好的效果。     

Ginkgo biloba extract enhances male copulatory behavior and reduces serum prolactin levels in rats

The aim of this study was to investigate the effects of Ginkgo biloba extract (EGb 761) on male copulatory behavior in rats. EGb 761 (1 mg/ml) induced significant production of testosterone (T) in rat Leydig cells in vitro. Its effects on sexual behavior were then tested in Long-Evans male rats after 7, 14, 21, or 28 days of oral gavage of vehicle (distilled water) or EGb 761 at doses of 10, 50, or 100 mg/kg. Administration of 50 mg/kg of EGb 761 for 28 days and of 100 mg/kg for 14 or 21 days significantly increased intromission frequency compared to controls on the same day. An increase in ejaculation frequency was seen after treatment with 50 mg/kg of EGb 761 for 14, 21, or 28 days when compared to either the control group on the same day or the same group on day 0. A reduction in ejaculation latency was only seen after administration of 50 mg/kg of EGb 761 for 14 days compared to the vehicle-treated group. After treatment for 28 days, no significant difference was seen in mount latency, intromission latency, serum T levels, reproductive organ weight, sperm number, or levels of the metabolite of dopamine, 3,4-dihydroxyphenylacetic acid in the brain with any dose of EGb 761, but significantly reduced serum prolactin levels and increased dopamine levels in the medial preoptic area and arcuate nucleus were seen at the dose of 50 mg/kg. These findings show that EGb 761 (especially at the dose of 50 mg/kg) enhances the copulatory behavior of male rats and suggest that the dopaminergic system, which regulates prolactin secretion, may be involved in the facilitatory effect of EGb 761.     

Genetics of gene expression characterizes response to selective breeding for alcohol preference

Numerous selective breeding experiments have been performed with rodents, in an attempt to understand the genetic basis for innate differences in preference for alcohol consumption. Quantitative trait locus (QTL) analysis has been used to determine regions of the genome that are associated with the behavioral difference in alcohol preference/consumption. Recent work suggests that differences in gene expression represent a major genetic basis for complex traits. Therefore, the QTLs are likely to harbor regulatory regions (eQTLs) for the differentially expressed genes that are associated with the trait. In this study, we examined brain gene expression differences over generations of selection of the third replicate lines of high and low alcohol‐preferring (HAP3 and LAP3) mice, and determined regions of the genome that control the expression of these differentially expressed genes (_deeQTLs). We also determined eQTL regions (_rveQTLs) for genes that showed a decrease in variance of expression levels over the course of selection. We postulated that _deeQTLs that overlap with _rveQTLs, and also with phenotypic QTLs, represent genomic regions that are affected by the process of selection. These overlapping regions controlled the expression of candidate genes (that displayed differential expression and reduced variance of expression) for the predisposition to differences in alcohol consumption by the HAP3/LAP3 mice.     

The effect of vibratory disturbance on sexual behaviour of the southern green stink bug Nezara viridula (Heteroptera, Pentatomidae)

The effect of vibratory disturbance on sexual behaviour and substrate-borne sound communication of the southern green stink bug, Nezara viridula L. was studied. Disturbance signals do not change the time N. viridula males need to locate the source of vibratory signals, but decrease the number of males responding with the calling and courtship song to calling females. Female N. viridula proceed calling during stimulation with disturbance signals but some of them change the song rhythm by skipping one or more signal intervals or emitting the repelling signals. The number of females which change the dominant frequency of the calling song decreases proportionally with increasing differences between the dominant frequency of the disturbance signals and the emitted female calling song. Variation of the song dominant frequency probably serves females to avoid interference by increasing the signal to noise ratio. Signal duration and repetition rate do not change significantly when the female is stimulated with the disturbance signals. This indicates that frequency shift by calling females is the main strategy for reducing interference by competitive signalers in N. viridula vibrational communication.     

The effect of saffron, Crocus sativus stigma, extract and its constituents, safranal and crocin on sexual behaviors in normal male rats

In this study, the aphrodisiac activities of Crocus sativus stigma aqueous extract and its constituents, safranal and crocin, were evaluated in male rats. The aqueous extract (80, 160 and 320 mg/kg body wt.), crocin (100, 200 and 400 mg/kg body wt.), safranal (0.1, 0.2 and 0.4 ml/kg), sildenafil (60 mg/kg body wt., as a positive control) and saline were administered intraperitoneally to male rats. Mounting frequency (MF), intromission frequency (IF), erection frequency (EF), mount latency (ML), intromission latency (IL) and ejaculation latency (EL) were the factors evaluated during the sexual behavior study. Crocin, at all doses, and the extract, especially at doses 160 and 320 mg/kg body wt., increased MF, IF and EF behaviors and reduced EL, IL and ML parameters. Safranal did not show aphrodisiac effects. The present study reveals an aphrodisiac activity of saffron aqueous extract and its constituent crocin.     

How does marriage affect length of life? Analysis of a French historical dataset from an evolutionary perspective

There are broadly two explanations for why human longevity appears to be extended by marriage. First, there is the social explanation, whereby the companionship, division of labour and the economic support that marriage offers is thought to extend life. Second, there is a selective explanation, whereby those individuals with high potential longevity are more attractive to the opposite sex and therefore more likely to get married. Here we analyse the “TRA” dataset from 19th century France, using an evolutionary approach to address the question of why marriage is linked to longevity, focussing particularly on sex differences. The dataset is based on death and marriage records from all of France between 1798 and 1901 and includes information on age at death, marriage and wealth for individuals whose surnames began with the letters TRA. We find that marriage is positively associated with longevity, particularly for men. In part, this is related to the higher rate of deaths for single males during marriageable age, as compared to a higher rate of deaths for females during marriage. There is a positive association between wealth (at death) and longevity for individuals who were single or married at death, with a stronger effect for singles. Analysis of the effect of spousal age gap on duration of survival after first marriage indicates that men who were married to younger women lived longer, whereas the longevity of women was not associated with the spousal age gap. We put forward an evolutionary perspective on marriage and longevity, hypothesizing that there is an important role for sexual selection in the association between marriage and longevity, with women selecting on characteristics associated with longevity, whilst men select on characteristics associated with reproductive potential.     

Time spent close to a sexual partner as a measure of female mate preference in a sex-role-reversed population of the blenny<Emphasis Type="Italic"> Salaria pavo</Emphasis> (Risso) (Pisces: Blenniidae)

In most species females do not exhibit conspicuous sexual behaviours and female mate preferences are often measured by means of the time spent close to males. In spite of its widespread use, in only a few studies has this measure been validated as a reliable indicator of female mate preference. Sex-role-reversed species offer a better opportunity to test female preferences, as females usually court males. We tested in a sex-role-reversed population of the blenny Salaria pavo (Risso) if the time spent by females close to males related to the number of courtship displays directed towards males, and whether these measures of female preference reliably predicted matings. Females were simultaneously presented with two males behind a glass partition and the time spent close to each male was measured. We then allowed females to have access to the males' compartments and measured the courtship behaviours performed by females towards each male and recorded with which of the males females spawned. Females spent more time close to the male that subsequently received more courtship displays, and the preferred male had a more developed head crest. However, both measures of female preference failed to predict matings. Females were often attacked by males and probably had, in some occasions, to spawn with the less preferred male. Females that spawned with the previously preferred male had more swollen bellies than females that spawned with the less preferred male, suggesting a male preference towards more ripe females. These results validate the use of "time spent close to a sexual partner" as a measure of female preference in S. pavo. We argue that matings may not always reliably indicate mate preferences, particularly in the less choosy sex.Communicated by R. Serrão Santos