Female- and male-specific signals of quality in the barn owl

Most bird studies of female signalling have been confined to species in which females display a male-ornament in a vestigial form. However, a great deal of benefit may be gained from considering phenotypic traits that are specific to females. This is because (1) sex-specific traits may signal sex-specific qualities and (2) females may develop a male-ornament not because they are selected to do so, but because fathers transmit to daughters the underlying genes for its expression (genetic correlation between the sexes). We investigated these two propositions in the barn owl Tyto alba, a species in which male plumage is lighter in colour and less marked with black spots than that of females. Firstly, we present published evidence that female plumage spottiness reflects parasite resistance ability. We also show that male plumage coloration is correlated with reproductive success, male feeding rate and heart mass. Secondly, cross-fostering experiments demonstrate that plumage coloration and spottiness are genetically correlated between the sexes. This implies that if a given trait value is selected in one sex, the other sex will indirectly evolve towards a similar value. This prediction is supported by the observation that female plumage coloration and spottiness resembled that of males, in comparisons at the level of Tyto alba alba populations, Tyto alba subspecies and Tyto species. Our results therefore support the hypothesis that sex-specific traits signal sex-specific qualities and that a gene for a sex-specific trait can be expressed in the other sex as the consequence of a genetic correlation between the sexes.

Differences between female and male adolescents regarding individual vulnerability to HIV

The objective of this study was to comparatively analyze male and female adolescents' vulnerability to HIV/AIDS, based on their knowledge, values and practices. This is an exploratory-descriptive study, performed using a quantitative approach. The students answered a questionnaire from which relevant questions were selected for the analysis. The participants were 207 adolescents, 43.5% male and 56.5% female. Most adolescents report having initiated sexual activities. It was observed that the participants have knowledge deficits regarding HIV transmission and safe sexual practices. Although they report knowing about condom use as a method of protection against HIV, they do not always use them. It was observed that there are values connected to the representations of gender, but it is noticed there is an evolution regarding the autonomy and power of the girls' negotiation regarding condom use.

What do we mean by Female and Male in Neurocognitive Experiments on Language?

For several years now, neuroscientific research has been striving towards fundamental answers to questions about the relevance of sex/gender to language processing in the brain. This research has been effected through the search for sex/gender differences in the neurobiology of language processing. Thus, the main aim has ever been to focus on the differentiation of the sexes/genders, failing to define what sex, what gender, what female or male is in neurolingustic research. In other words, although neuroscientific findings have provided key insights into the brain functioning of women and men, neuropsychology has rarely questioned the complexity of the sex/gender variable beyond biology. What does “female” or “male” mean in human neurocognition; how are operationalisations implemented along the axes of “femaleness” or “maleness”; or what biological evidence is used to register the variables sex and/or gender? In the neurosciences as well as in neurocognitive research, questions such as these have so far not been studied in detail, even if they are highly significant for the scientific process. Instead, the variable of sex/gender has always been thought as solely dichotomous (as either female or male), oppositional and exclusionary of each other. Here, this theoretical contribution sets in. Based on findings in neuroscience and concepts in gender theory, this poster is dedicated to the reflection about what sex/gender is in the neuroscience of language processing. Following this aim, two levels of interest will be addressed. First: How do we define sex/gender at the level of participants? And second: How do we define sex/gender at the level of the experimental task? For the first, a multifactorial registration (work in progress) of the variable sex/gender will be presented, i.e. a tool that records sex/gender in terms of biology and social issues as well as on a spectrum between femaleness and maleness. For the second, the compulsory dichotomy of a gendered task when neurolinguistically approaching our cognitions of sex/gender will be explored.

Is Pairing with a Relative Heritable? : Estimating Female and Male Genetic Contributions to the Degree of Biparental Inbreeding in Song Sparrows (Melospiza melodia)

We thank the Tsawout and Tseycum First Nation bands for access to Mandarte, everyone who contributed to the long-term data collection, and the European Research Council and Royal Society for funding. We thank J.D. Hadfield, P. Bijma, E. Postma, and L.F. Keller for illuminatingdiscussions. Also, L.E.B. Kruuk, R. Bonduriansky, and an anonymous reviewer provided insightful comments that improved the manuscript.

Body size in the field cricket Gryllus integer (Orthoptera : Gryllidae) :heritability and male mating success

The influence of male body weight on the aggressive and mating behaviour of male Gryllus integer was studied under laboratory conditions. The relationship between adult age and weight was first determined; female weight increased and male weight decreased with age. Virgin males that had been isolated since the adult molt were paired for similar age and a difference in weight of greater than 200 mg. Paired males and a virgin female were observed in a glass arena for 24 minutes or until a mating occurred. Larger males mated significantly more often than smaller males. Larger males attacked more often, were more successful in aggressive encounters and had more contact with the female. Males that did not mate had lower rates of courtship and mounts than males that mated. Females in trials that did not result in a mating were signifcantly heavier than females in trials that resulted in a mating. Larger males that mated were significantly closer in weight to the weight of the female than larger males in trials that did not result in a mating. Larger males in trials that did not result in a mating had higher rates of aggressive stridulation than larger males that mated. Male weight is therefore important in mating success; fitness traits should theoretically show low genetic variability. However, significant heritability values were found for live weight, dry weight, head width, pronotum width and length, hind femur length and forewing length when estimated from the regression of offspring on mid-parent values, offspring and female and male values separately and full-sib correlations. The heritability of hind femur width was significant when estimated from the regression of offspring on male parent and from full-sib correlations. Heritability estimates of forewing length were significantly higher when estimated from the regression of offspring on female parent than when estimated from the regression of offspring on male parent. High phenotypic, genetic and environmental correlations were found between all pairs of traits. Data on male mating success and the heritability of fitness traits were discussed in terms of the maintenance of genetic variability.

Facing Aggression: Cues Differ for Female versus Male Faces

The facial width-to-height ratio (face ratio), is a sexually dimorphic metric associated with actual aggression in men and with observers’ judgements of aggression in male faces. Here, we sought to determine if observers’ judgements of aggression were associated with the face ratio in female faces. In three studies, participants rated photographs of female and male faces on aggression, femininity, masculinity, attractiveness, and nurturing. In Studies 1 and 2, for female and male faces, judgements of aggression were associated with the face ratio even when other cues in the face related to masculinity were controlled statistically. Nevertheless, correlations between the face ratio and judgements of aggression were smaller for female than for male faces (F1,36= 7.43, p= 0.01). In Study 1, there was no significant relationship between judgements of femininity and of aggression in female faces. In Study 2, the association between judgements of masculinity and aggression was weaker in female faces than for male faces in Study 1. The weaker association in female faces may be because aggression and masculinity are stereotypically male traits. Thus, in Study 3, observers rated faces on nurturing (a stereotypically female trait) and on femininity. Judgements of nurturing were associated with femininity (positively) and masculinity (negatively) ratings in both female and male faces. In summary, the perception of aggression differs in female versus male faces. The sex difference was not simply because aggression is a gendered construct; the relationships between masculinity/femininity and nurturing were similar for male and female faces even though nurturing is also a gendered construct. Masculinity and femininity ratings are not associated with aggression ratings nor with the face ratio for female faces. In contrast, all four variables are highly inter-correlated in male faces, likely because these cues in male faces serve as ‘‘honest signals’’.

CONTRASTING PHYLOGEOGRAPHIC PATTERNS IN MITOCHONDRIAL DNA AND MICROSATELLITES: EVIDENCE OF FEMALE PHILOPATRY AND MALE-BIASED GENE FLOW AMONG REGIONAL POPULATIONS OF THE BLUE-AND-YELLOW MACAW (PSITTACIFORMES: ARA ARARAUNA) IN BRAZIL

Comparing the patterns of population differentiation among genetic markers with different modes of inheritance call provide insights into patterns of sex-biased dispersal and gene flow. The blue-and-yellow Macaw (Ara ararauna) is a Neotropical parrot with a broad geographic distribution ill South America. However, little is known about the natural history and current status Of remaining wild populations, including levels of genetic variability. The progressive decline and possible fragmentation of populations may endanger this species in the near future. We analyzed mitochondrial DNA (mtDNA) control-region sequences and six microsatellite 106 Of Blue-and-yellow Macaws sampled throughout their geographic range ill Brazil to describe population genetic Structure, to make inferences about historical demography and dispersal behavior, and to provide insight for conservation efforts. Analyses of population genetic structure based on mtDNA showed evidence of two major populations ill western and eastern Brazil that share a few low-frequency haplotypes. This phylogeographic pattern seems to have originated by the historical isolation of Blue-and-yellow Macaw populations similar to 374,000 years ago and has been maintained by restricted gene flow and female philopatry. By contrast, variation ill biparentally inherited microsatellites was not structured geographically, Male-biased dispersal and female philopatry best explain the different patterns observed in these two markers. Because females disperse less than males, the two regional populations with well-differentiated mtDNA haplogroups should be considered two different management units for conservation purposes. Received 4 November 2007 accepted 10 December 2008.

Education and male-female differences in later-life cognition: international evidence from latin america and the Caribbean.

This study explores the role of early-life education for differences in cognitive functioning between men and women aged 60 and older from seven major urban areas in Latin America and the Caribbean. After documenting statistically significant differences in cognitive functioning between men and women for six of the seven study sites, I assess the extent to which these differences can be explained by prevailing male-female differences in education. I decompose predicted male-female differences in cognitive functioning based on various statistical models for later-life cognition and find robust evidence that male-female differences in education are a major driving force behind cognitive functioning differences between older men and women. This study therefore suggests that early-life differences in educational attainment between boys and girls during childhood have a lasting impact on gender inequity in cognitive functioning at older ages. Increases in educational attainment and the closing of the gender gap in education in many countries in Latin America and the Caribbean may thus result in both higher levels and a more gender-equitable distribution of later-life cognition among the future elderly in those countries.

Myospila bekilyana (Séguy) (Diptera, Muscidae, Mydaeinae): redescription of male and female and description of terminalia

Myospila bekilyana Séguy (Diptera, Muscidae, Mydaeainae) is an endemic species from Madagascar. Since the original description, the species has been referred in literature only in catalogues. A material recently collected by the Madagascar Arthropod Biodiversity project, mostly deposited at the California Academy of Sciences collection enabled the exam of a large series of this species. Male and female are herein redescribed and the terminalia of both sexes are described and illustrated for the first time. The paper also records Myospila as a new host for Stylogaster Macquart (Diptera, Conopidae).

Sex-specific estimates of dispersal show female philopatry and male dispersal in a promiscuous amphibian, the alpine salamander (Salamandra atra).

Amphibians display wide variations in life-history traits and life cycles that should prove useful to explore the evolution of sex-biased dispersal, but quantitative data on sex-specific dispersal patterns are scarce. Here, we focused on Salamandra atra, an endemic alpine species showing peculiar life-history traits. Strictly terrestrial and viviparous, the species has a promiscuous mating system, and females reproduce only every 3 to 4 years. In the present study, we provide quantitative estimates of asymmetries in male vs. female dispersal using both field-based (mark-recapture) and genetic approaches (detection of sex-biased dispersal and estimates of migration rates based on the contrast in genetic structure across sexes and age classes). Our results revealed a high level of gene flow among populations, which stems exclusively from male dispersal. We hypothesize that philopatric females benefit from being familiar with their natal area for the acquisition and defence of an appropriate shelter, while male dispersal has been secondarily favoured by inbreeding avoidance. Together with other studies on amphibians, our results indicate that a species' mating system alone is a poor predictor of sex-linked differences in dispersal, in particular for promiscuous species. Further studies should focus more directly on the proximate forces that favour or limit dispersal to refine our understanding of the evolution of sex-biased dispersal in animals.