Clinical chemistry and hematology values in a Caribbean population of African green monkeys

Background Hematology and clinical chemistry (HCC) reference values are critical in veterinary practice and in vivo pre‐clinical research, enabling detection of health abnormalities, response to therapeutic intervention or adverse toxicological effects, as well as monitoring of clinical management. Methods In this report, reference ranges for 46 HCC parameters were characterized in 331 wild‐caught and colony‐bred African green monkeys. Effects of sex, weight and duration of captivity were determined by one‐way analysis of variance. Results Significant sex differences were observed for several HCC parameters. Significant differences were also observed for select HCC variables between newly caught animals and those held in captivity for 1–12 months or longer. Conclusions Comparison of this data with other non‐human primate species and humans highlights similarities and disparities between species. Potential causes of interpopulation variability and relevance to the use of the African green monkey as a non‐human primate model are discussed.     

Bad to the bone: facial structure predicts unethical behaviour

Researchers spanning many scientific domains, including primatology, evolutionary biology and psychology, have sought to establish an evolutionary basis for morality. While researchers have identified social and cognitive adaptations that support ethical behaviour, a consensus has emerged that genetically determined physical traits are not reliable signals of unethical intentions or actions. Challenging this view, we show that genetically determined physical traits can serve as reliable predictors of unethical behaviour if they are also associated with positive signals in intersex and intrasex selection. Specifically, we identify a key physical attribute, the facial width-to-height ratio, which predicts unethical behaviour in men. Across two studies, we demonstrate that men with wider faces (relative to facial height) are more likely to explicitly deceive their counterparts in a negotiation, and are more willing to cheat in order to increase their financial gain. Importantly, we provide evidence that the link between facial metrics and unethical behaviour is mediated by a psychological sense of power. Our results demonstrate that static physical attributes can indeed serve as reliable cues of immoral action, and provide additional support for the view that evolutionary forces shape ethical judgement and behaviour.     

In your face: facial metrics predict aggressive behaviour in the laboratory and in varsity and professional hockey players

Facial characteristics are an important basis for judgements about gender, emotion, personality, motivational states and behavioural dispositions. Based on a recent finding of a sexual dimorphism in facial metrics that is independent of body size, we conducted three studies to examine the extent to which individual differences in the facial width-to-height ratio were associated with trait dominance (using a questionnaire) and aggression during a behavioural task and in a naturalistic setting (varsity and professional ice hockey). In study 1, men had a larger facial width-to-height ratio, higher scores of trait dominance, and were more reactively aggressive compared with women. Individual differences in the facial width-to-height ratio predicted reactive aggression in men, but not in women (predicted 15% of variance). In studies 2 (male varsity hockey players) and 3 (male professional hockey players), individual differences in the facial width-to-height ratio were positively related to aggressive behaviour as measured by the number of penalty minutes per game obtained over a season (predicted 29 and 9% of the variance, respectively). Together, these findings suggest that the sexually dimorphic facial width-to-height ratio may be an 'honest signal' of propensity for aggressive behaviour.     

Antagonistic natural selection revealed by molecular sex identification of nestling collared flycatchers

Natural selection may act in different directions during different life-history stages, or in different directions on different classes of individuals. Antagonistic selection of this kind may be an important mechanism by which additive genetic variation for quantitative traits is maintained, and can prevent populations or species reaching local adaptive peaks. This paper reports the results of a study of viability selection on morphological traits of nestling collared flycatchers Ficedula albicollis . Analyses performed without knowledge of the sex of nestlings suggested that no selection was occurring on these traits. However, using molecular sex identification with the avian CHD gene, it is shown that selection acts in different directions on male and female body size from fledging to breeding, apparently favouring relatively small males and large females. The results suggest that differential selection on male and female nestlings may contribute to purely phenotypic sexual size dimorphism in this species. These findings highlight the potential of newly developed molecular sexing techniques to reveal the consequences of an individual's gender for many aspects of its life history in taxa where gender cannot be determined on the basis of external appearance.     

Sex ratio selection and multi-factorial sex determination in the housefly: a dynamic model

Sex determining (SD) mechanisms are highly variable between different taxonomic groups and appear to change relatively quickly during evolution. Sex ratio selection could be a dominant force causing such changes. We investigate theoretically the effect of sex ratio selection on the dynamics of a multi-factorial SD system. The system considered resembles the naturally occurring three-locus system of the housefly, which allows for male heterogamety, female heterogamety and a variety of other mechanisms. Sex ratio selection is modelled by assuming cost differences in the production of sons and daughters, a scenario leading to a strong sex ratio bias in the absence of constraints imposed by the mechanism of sex determination. We show that, despite of the presumed flexibility of the SD system considered, equilibrium sex ratios never deviate strongly from 1 : 1. Even if daughters are very costly, a male-biased sex ratio can never evolve. If sons are more costly, sex ratio can be slightly female biased but even in case of large cost differences the bias is very small (<10% from 1 : 1). Sex ratio selection can lead to a shift in the SD mechanism, but cannot be the sole cause of complete switches from one SD system to another. In fact, more than one locus remains polymorphic at equilibrium. We discuss our results in the context of evolution of the variable SD mechanism found in natural housefly populations.     

Immunity and the expression of a secondary sexual trait in a horned beetle

Resource-based trade-offs are known to be important in determininginvestment in both sexual ornamentation and immunity in insects.Because of the strict resource limitation experienced duringmetamorphosis, we predict that if insects are trading off ornamentsize and immunity this should be most apparent immediately aftereclosion and that the relationship between sexual ornament sizeand immunity should change with maturation feeding because ofthe changing patterns of resource availability during this process.We therefore present an investigation into the relationshipbetween morphology, sex, and two measures of immune response(phenoloxidase [PO] activity and encapsulation ability) in thehorned beetle Euoniticellus intermedius, immediately after eclosionand after maturation feeding. Both measures increased with maturation,with sex differences in PO activity becoming discernable aftermaturation feeding. PO activity was positively correlated withhorn length in male beetles both on eclosion and after maturationfeeding, and encapsulation ability was positively correlatedwith elytra length. We conclude that resource limitation inthe pupating insect does have effects on immunity but that thisresource limitation does not translate into a measurable trade-offbetween horn length and immunity. The correlation between hornlength and PO activity may arise because both horn length andPO activity are correlated with the same elements of the animal'sbiology that allow some animals both to grow a long horn andto sustain a higher level of PO activity.     

稻褐飞虱致害性遗传与性别的关联性研究

以单雌蜜露排泄量和体重增量作为致害性指标,研究了稻褐飞虱Nilaparvata lugens (Stål)的致害性遗传与性别的关联性。褐飞虱弱致害种群（TN1种群）与强致害种群（Mudgo种群或ASD7种群）（已分别用水稻品种TN1、Mudgo和ASD7强迫饲养82代）在抗虫品种水稻上的致害力差异明显,适宜作为遗传分析的亲本材料。当用蜜露排泄量作为致害性指标时,两种处理（TN1种群与Mudgo种群,TN1种群与ASD7种群）正、反杂交的F₁代雌成虫平均蜜露排泄量存在极显著差异,由此可以推断正交F₁代群体与反交F₁代群体致害性存在明显差别。用体重增量作为致害性指标进行实验,得到的结论与上述研究完全一致。以上的结果可推测稻褐飞虱致害性可能属于伴性遗传。     

Differential selection between the sexes and selection for sex

Anisogamy is known to generate an important cost for sexual reproduction (the famous "twofold cost of sex"). However, male-female differences may have other consequences on the evolution of sex, due to the fact that selective pressures may differ among the sexes. On the one hand, intralocus sexual conflict should favor asexual females, which can fix female-beneficial, male-detrimental alleles. On the other hand, it has been suggested repeatedly that sexual selection among males may help to purge the mutation load, providing an advantage to sexual females. However, no analytical model has computed the strength of selection acting on a modifier gene affecting the frequency of sexual reproduction when selection differs between the sexes. In this article, we analyze a two-locus model using two approaches: a quasi-linkage-equilibrium (QLE) analysis and a local stability analysis, whose predictions are verified using a multilocus simulation. We find that costly sex can be maintained when selection is stronger in males than in females, but acts in the same direction in both. Complete asexuality, however, evolves under any other form of selection. Finally, we discuss how experimental measurements of fitness variances and covariances between sexes could be used to determine the overall direction and strength on selection for sex arising from differences in selection between males and females.     

Parents’ genetic dissimilarity and offspring sex in a polygynous mammal

Offspring quality may benefit from genetic dissimilarity between parents. However, genetic dissimilarity may trade‐off with additive genetic benefits. We hypothesized that when sexual selection produces sex‐specific selective scenarios, the relative benefits of additive genetic vs. dissimilarity may differ for sons and daughters. Here we study a sample of 666 red deer (Cervus elaphus) microsatellite genotypes, including males, females and their foetuses, from 20 wild populations in Spain (the main analyses are based on 241 different foetuses and 190 mother‐foetus pairs). We found that parental lineages were more dissimilar in daughters than in sons. On average, every mother was less related to her mate than to the sample of fathers in the population when producing daughters not sons. Male foetuses conceived early in the rutting season were much more inbred than any other foetuses. These differences maintained through gestation length, ruling out intrauterine mortality as a cause for the results, and indicating that the potential mechanism producing the association between parents’ dissimilarity and offspring sex should operate close to mating or conception time. Our findings highlight the relevance of considering the sex of offspring when studying genetic similarity between parents.     

Female competition and aggression: interdisciplinary perspectives

This paper introduces a Theme Issue combining interdisciplinary perspectives in the study of female competition and aggression. Despite a history of being largely overlooked, evidence is now accumulating for the widespread evolutionary significance of female competition. Here, we provide a synthesis of contributions to this Theme Issue on humans and other vertebrates, and highlight directions for future research. Females compete for resources needed to survive and reproduce, and for preferred mates. Although female aggression takes diverse forms, under most circumstances relatively low-risk competitive strategies are favoured, most probably due to constraints of offspring production and care. In social species, dominance relationships and threats of punishment can resolve social conflict without resort to direct aggression, and coalitions or alliances may reduce risk of retaliation. Consistent with these trends, indirect aggression is a low cost but effective form of competition among young women. Costs are also minimized by flexibility in expression of competitive traits, with aggressive behaviour and competitive signalling tailored to social and ecological conditions. Future research on female competition and the proximate mediators of female aggression will be greatly enhanced by opportunities for interdisciplinary exchange, as evidenced by contributions to this Theme Issue.     

Cognitive differences in dream content between Argentine males and females using quantitative content analysis.

This study asked the question, Are there significant content differences between male and female dream reports obtained in seminars conducted in Argentina? Each of the 100 female and 100 male participants contributed one recent dream report during dream seminars held in Argentina between 1990 and 1998. Dream reports were scored using Hall and Van de Castle's System of Content Analysis. Major findings revealed that Argentine males reported significantly more aggressions per character and a higher percentage of dreamers as the aggressor than reported by females. They also reported more dreams with at least one success than reported by females. In contrast, females scored significantly higher on both the Self-Negativity index and the Negative Emotions index compared to males. Although some findings were similar to past studies using American participants, others were unique to this study and may be attributable to the particular sample used, or may suggest actual underlying cultural patterns of contemporary Argentine men and women. Results are discussed in terms of Hall's continuity hypothesis and Domhoff's cognitive model of dreaming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The cremasteric neuromuscular complex in male and female grey short-tailed opossums (Monodelphis domestica)

In marsupials, both sexes possess a cremaster muscle, that of the female being attached to the mammary gland and surrounding subcutaneous tissues. In the grey short‐tailed opossum, the muscle in both sexes has a distinct proximal origin from the anterior superior iliac spine. The number of muscle fibres is higher in male than in female opossums on average, but the difference is not statistically significant. Retrograde tracing, achieved by injecting B‐cholera toxin into the muscle, showed that labelled neurons occupied several spinal cord segments, the bulk being in L2–L4. There was no overall sex difference in the number of labelled neurons. It is concluded that cremaster muscles are present in both sexes of the grey short‐tailed opossum Monodelphis domestica, contain approximately equal numbers of fibres, and differ only in their insertion target. Since the motor innervation also shows no dimorphisms in this species, it is concluded that the whole neuromuscular complex is homologous in the two sexes. This is in marked contrast to the situation in adult eutherian mammals where the muscle is possesed by males only, and where the cremasteric nucleus is highly dimorphic in terms of motor neuron numbers.