A Macroevolutionary Perspective on Multiple Sexual Traits in the Phasianidae (Galliformes)

Traits involved in sexual signaling are ubiquitous among animals. Although a single trait appears sufficient to convey information, many sexually dimorphic species exhibit multiple sexual signals, which may be costly to signalers and receivers. Given that one signal may be enough, there are many microevolutionary hypotheses to explain the evolution of multiple signals. Here we extend these hypotheses to a macroevolutionary scale and compare those predictions to the patterns of gains and losses of sexual dimorphism in pheasants and partridges. Among nine dimorphic characters, including six intersexual signals and three indicators of competitive ability, all exhibited both gains and losses of dimorphism within the group. Although theories of intersexual selection emphasize gain and elaboration, those six characters exhibited greater rates of loss than gain; in contrast, the competitive traits showed a slight bias towards gains. The available models, when examined in a macroevolutionary framework, did not yield unique predictions, making it difficult to distinguish among them. Even with this limitation, when the predictions of these alternative models were compared with the heterogeneous patterns of evolution of dimorphism in phasianids, it is clear that many different selective processes have been involved in the evolution of sexual signals in this group

Social conformity affects experimental measurement of boldness in male but not female monk parakeets (\u3ci\u3eMyiopsitta monachus\u3c/i\u3e)

The standard approach for characterizing boldness rarely considers the influence of social environment on the expression of boldness in group-living animals. We studied a wild-caught, captive population of monk parakeets (Myiopsitta monachus) to investigate the impact of conspecific presence on boldness — a personality trait in monk parakeets — in a controlled environment. We quantified seven boldness metrics across three types of behavioural assay: novel object, emergence, and predator exposure tests in the presence of a companion pair of flock mates. Because of the high degree of sociality in this species, we hypothesized that the presence of companion birds would facilitate the focal individuals’ behavioural responses (i.e., increase the average boldness level). We found that behavioural response in a risky foraging context was inversely correlated between solitary and social condition in males, but not in females. Our results have implications for characterizing sex-specific differences of risk-taking behaviour in social animals

A simple measure with complex determinants: investigation of the correlates of self-rated health in older men and women from three continents

Self-rated health is commonly employed in research studies that seek to assess the health status of older individuals. Perceptions of health are, however, influenced by individual and societal level factors that may differ within and between countries. This study investigates levels of self-rated health (SRH) and correlates of SRH among older adults in Australia, United States of America (USA), Japan and South Korea. We conclude that when examining correlates of SRH, the similarities are greater than the differences between countries. There are however differences in levels of SRH which are not fully accounted for by the health correlates. Broad generalizations about styles of responding are not helpful for understanding these differences, which appear to be country- and possibly cohort-specific. When using SRH to characterize the health status of older people, it is important to consider earlier life experiences of cohorts as well as national and individual factors in later life. Further research is required to understand the complex societal influences on perceptions of health.The Australian data on which this research is based were drawn from several Australian longitudinal studies including: the Australian Longitudinal Study of Ageing (ALSA), the Australian Longitudinal Study of Women’s Health (ALSWH) and the Personality And Total Health Through Life Study (PATH). These studies were pooled and harmonized for the Dynamic Analyses to Optimize Ageing (DYNOPTA) project. DYNOPTA was funded by a National Health and Medical Research Council (NHMRC) grant (# 410215)

Impact of CD4 and CD8 dynamics and viral rebounds on loss of virological control in HIV controllers

Objective: HIV controllers (HICs) spontaneously maintain HIV viral replication at low level without antiretroviral therapy (ART), a small number of whom will eventually lose this ability to control HIV viremia. The objective was to identify factors associated with loss of virological control. Methods: HICs were identified in COHERE on the basis of \ue2\u89\ua55 consecutive viral loads (VL) \ue2\u89\ua4500 copies/mL over \ue2\u89\ua51 year whilst ART-naive, with the last VL \ue2\u89\ua4500 copies/mL measured \ue2\u89\ua55 years after HIV diagnosis. Loss of virological control was defined as 2 consecutive VL >2000 copies/mL. Duration of HIV control was described using cumulative incidence method, considering loss of virological control, ART initiation and death during virological control as competing outcomes. Factors associated with loss of virological control were identified using Cox models. CD4 and CD8 dynamics were described using mixed-effect linear models. Results: We identified 1067 HICs; 86 lost virological control, 293 initiated ART, and 13 died during virological control. Six years after confirmation of HIC status, the probability of losing virological control, initiating ART and dying were 13%, 37%, and 2%. Current lower CD4/CD8 ratio and a history of transient viral rebounds were associated with an increased risk of losing virological control. CD4 declined and CD8 increased before loss of virological control, and before viral rebounds. Discussion: Expansion of CD8 and decline of CD4 during HIV control may result from repeated low-level viremia. Our findings suggest that in addition to superinfection, other mechanisms, such as low grade viral replication, can lead to loss of virological control in HICs

New genetic loci link adipose and insulin biology to body fat distribution.

Body fat distribution is a heritable trait and a well-established predictor of adverse metabolic outcomes, independent of overall adiposity. To increase our understanding of the genetic basis of body fat distribution and its molecular links to cardiometabolic traits, here we conduct genome-wide association meta-analyses of traits related to waist and hip circumferences in up to 224,459 individuals. We identify 49 loci (33 new) associated with waist-to-hip ratio adjusted for body mass index (BMI), and an additional 19 loci newly associated with related waist and hip circumference measures (P < 5 × 10(-8)). In total, 20 of the 49 waist-to-hip ratio adjusted for BMI loci show significant sexual dimorphism, 19 of which display a stronger effect in women. The identified loci were enriched for genes expressed in adipose tissue and for putative regulatory elements in adipocytes. Pathway analyses implicated adipogenesis, angiogenesis, transcriptional regulation and insulin resistance as processes affecting fat distribution, providing insight into potential pathophysiological mechanisms

Social conformity affects experimental measurement of boldness in male but not female monk parakeets (\u3ci\u3eMyiopsitta monachus\u3c/i\u3e)

The standard approach for characterizing boldness rarely considers the influence of social environment on the expression of boldness in group-living animals. We studied a wild-caught, captive population of monk parakeets (Myiopsitta monachus) to investigate the impact of conspecific presence on boldness — a personality trait in monk parakeets — in a controlled environment. We quantified seven boldness metrics across three types of behavioural assay: novel object, emergence, and predator exposure tests in the presence of a companion pair of flock mates. Because of the high degree of sociality in this species, we hypothesized that the presence of companion birds would facilitate the focal individuals’ behavioural responses (i.e., increase the average boldness level). We found that behavioural response in a risky foraging context was inversely correlated between solitary and social condition in males, but not in females. Our results have implications for characterizing sex-specific differences of risk-taking behaviour in social animals

When should males lek? Insights from a dynamic state variable model

A central focus in the study of lek evolution is to understand the clustering of male mating territories. Lekking males typically defend small clumped territories and experience intense competition associated with dense aggregations. We used dynamic state variable modeling to evaluate three alternative selective pressures proposed to explain the evolution of lekking. These are female mating bias for large clusters, reduction in predation risk in large clusters, and male harassment of estrous females. We modeled male mating decisions during a single breeding season using a lekking ungulate as a model system. Males could choose from eight alternative tactics that included a nonreproductive tactic, territorial tactics ranging from low to high clustering, and the option to join a mixed-sex herd. The model predicted a state- and time-dependent strategy that maximizes mating success over the course of the season. We then simulated a population of 100 males that used the optimal strategy and calculated the proportion of the population that adopted each tactic. Our model generated unique predictions for the three selective pressures we considered. Female mating bias, when nonlinearly related to cluster size, had the greatest potential to generate large clusters of territorial males, whereas predation risk and harassment of females typically did not promote male clustering. More generally, our model highlights the conditions that will favor lekking. Lek-like clustering was consistently produced when the benefits in clustering increased in specific nonlinear ways. Our model thus emphasizes clarifying the shapes of relationships between potential selective factors and the size of territory clusters. Copyright 2003.dynamic optimization; female preference; lek evolution; predation risk; sexual harassment

Effect of sand texture on nest quality and mating success in a fish with parental care

Nest quality is an important aspect of courtship and mate choice, offering females direct benefits through offspring survival and, if it reflects male genetic quality, also indirect ones. Nest characteristics may thus affect both male mating success and reproductive success. Using the sand goby, where males build nests by covering mussel shells or stones in sand, we tested the role of nest material in male nest site choice, nest construction, and female mate choice. We examined the effect of sand texture (coarse or fine, depending on grain size) in two different settings: (A) when the male was free to choose between nest sites in different sand textures and other males were absent, and (B) when the male was denied a choice of sand texture and another male was present behind a partition. In (B), we also examined the effects of sand texture on female preference. In (A), males took up nest sites equally often in coarse and fine sand, but nests built in fine sand had greater sand cover. In (B), there was no difference in nest sand cover, but a greater number of males, and in particular males that weighed less and had been assigned coarse sand, refrained from building a nest at all. This suggests that sand texture does affect nest building in sand gobies, manifesting itself directly through nest sand cover, or indirectly through failure to build a nest. Moreover, we found that females preferred to spawn in well-covered nests regardless of sand texture. Nests offer eggs and offsp ring protection from predators and inclement weather, but building material may af fect both the Properties of the nest and the quality of the construction. Here, we presented male sand gobies with nest sites in either fine-grained or coarse- grained sand, assessed the sand cover of the nest, and allowed females to spawn. We found that grain size influenced the amount of sand cover on the nest and af fected the fraction of males that refrained from building a nest. Female spawning decision depended on the amount of sand cover, but neither males nor females expressed a preference for sand texture. Our results show that nest material is an important but indirect aspect of mating success, which may influence habitat utilization in the wild. Gobiidae, Mate choice, Nest building, Reproduction, Sand gobyacceptedVersio