Sex differences in adult lifespan and aging rates of mortality across wild mammals

In human populations, women consistently outlive men, which suggests profound biological foundations for sex differences in survival. Quantifying whether such sex differences are also pervasive in wild mammals is a crucial challenge in both evolutionary biology and biogerontology. Here, we compile demographic data from 134 mammal populations, encompassing 101 species, to show that the female’s median lifespan is on average 18.6% longer than that of conspecific males, whereas in humans the female advantage is on average 7.8%. On the contrary, we do not find any consistent sex differences in aging rates. In addition, sex differences in median adult lifespan and aging rates are both highly variable across species. Our analyses suggest that the magnitude of sex differences in mammalian mortality patterns is likely shaped by local environmental conditions in interaction with the sex-specific costs of sexual selection.

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Sexual selection, the division of labor, and the evolution of sex differences

Behavioral and Brain Sciences ◽

10.1017/s0140525x98221248 ◽

1998 ◽

Vol 21 (3) ◽

pp. 444-447 ◽

Cited By ~ 5

Author(s):

David C. Geary

Keyword(s):

Sex Differences ◽

Sexual Selection ◽

Sex Ratio ◽

Division Of Labor ◽

Operational Sex Ratio ◽

Female Competition ◽

Human Populations ◽

Human Sex Differences ◽

Male Choice ◽

Relative Contribution

Sexual selection traditionally involves male-male competition and female choice, but in some species, including humans, sexual selection can also involve female-female competition and male choice. The degree to which one aspect of sexual selection or another is manifest in human populations will be influenced by a host of social and ecological variables, including the operational sex ratio. These variables are discussed in connection with the relative contribution of sexual selection and the division of labor to the evolution of human sex differences.

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A Primer of Population Genetics and Genomics

10.1093/oso/9780198862291.001.0001 ◽

2020 ◽

Author(s):

Daniel L. Hartl

Keyword(s):

Population Genetics ◽

Complex Traits ◽

Evolutionary Biology ◽

Knowledge Retention ◽

Learning By Doing ◽

Human Populations ◽

Gene Drive ◽

Molecular Population Genetics ◽

Genetics And Genomics ◽

And Mathematics

A Primer of Population Genetics and Genomics, 4th edition, has been completely revised and updated to provide a concise but comprehensive introduction to the basic concepts of population genetics and genomics. Recent textbooks have tended to focus on such specialized topics as the coalescent, molecular evolution, human population genetics, or genomics. This primer bucks that trend by encouraging a broader familiarity with, and understanding of, population genetics and genomics as a whole. The overview ranges from mating systems through the causes of evolution, molecular population genetics, and the genomics of complex traits. Interwoven are discussions of ancient DNA, gene drive, landscape genetics, identifying risk factors for complex diseases, the genomics of adaptation and speciation, and other active areas of research. The principles are illuminated by numerous examples from a wide variety of animals, plants, microbes, and human populations. The approach also emphasizes learning by doing, which in this case means solving numerical or conceptual problems. The rationale behind this is that the use of concepts in problem-solving lead to deeper understanding and longer knowledge retention. This accessible, introductory textbook is aimed principally at students of various levels and abilities (from senior undergraduate to postgraduate) as well as practising scientists in the fields of population genetics, ecology, evolutionary biology, computational biology, bioinformatics, biostatistics, physics, and mathematics.

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Sex differences in skinfold variability across human populations and during the life cycle

Annals of Human Biology ◽

10.1080/03014460701367942 ◽

2007 ◽

Vol 34 (3) ◽

pp. 377-392 ◽

Cited By ~ 6

Author(s):

Elisabetta Marini ◽

Stefano Cabras ◽

Esther Rebato ◽

Roberto Buffa ◽

Itziar Salces ◽

...

Keyword(s):

Sex Differences ◽

Life Cycle ◽

Human Populations

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Evolution of correlated complexity in the radically different courtship signals of birds-of-paradise

10.1101/351437 ◽

2018 ◽

Author(s):

Russell A. Ligon ◽

Christopher D. Diaz ◽

Janelle L. Morano ◽

Jolyon Troscianko ◽

Martin Stevens ◽

...

Keyword(s):

Sexual Selection ◽

Natural Selection ◽

Evolutionary Biology ◽

Evolutionary Dynamics ◽

Functional Integration ◽

Empirical Support ◽

Evolutionary Patterns ◽

Evolutionary Innovation ◽

Birds Of Paradise ◽

Analytical Approaches

Ornaments used in courtship often vary wildly among species, reflecting the evolutionary interplay between mate preference functions and the constraints imposed by natural selection. Consequently, understanding the evolutionary dynamics responsible for ornament diversification has been a longstanding challenge in evolutionary biology. However, comparing radically different ornaments across species, as well as different classes of ornaments within species, is a profound challenge to understanding diversification of sexual signals. Using novel methods and a unique natural history dataset, we explore evolutionary patterns of ornament evolution in a group - the birds-of-paradise - exhibiting dramatic phenotypic diversification widely assumed to be driven by sexual selection. Rather than the tradeoff between ornament types originally envisioned by Darwin and Wallace, we found positive correlations among cross-modal (visual/acoustic) signals indicating functional integration of ornamental traits into a composite unit - the courtship phenotype. Furthermore, given the broad theoretical and empirical support for the idea that systemic robustness - functional overlap and interdependency - promotes evolutionary innovation, we posit that birds-of-paradise have radiated extensively through ornamental phenotype space as a consequence of the robustness in the courtship phenotype that we document at a phylogenetic scale. We suggest that the degree of robustness in courtship phenotypes among taxa can provide new insights into the relative influence of sexual and natural selection on phenotypic radiations.Author SummaryAnimals frequently vary widely in ornamentation, even among closely related species. Understanding the patterns that underlie this variation is a significant challenge, requiring comparisons among drastically different traits - like comparing apples to oranges. Here, we use novel analytical approaches to quantify variation in ornamental diversity and richness across the wildly divergent birds-of-paradise, a textbook example of how sexual selection can profoundly shape organismal phenotypes. We find that color and acoustic complexity, along with behavior and acoustic complexity, are positively correlated across evolutionary time-scales. Positive covariation among ornament classes suggests that selection is acting on correlated suites of traits - a composite courtship phenotype - and that this integration may be partially responsible for the extreme variation we see in birds-of-paradise.

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Sex allocation conflict and sexual selection throughout the lifespan of eusocial colonies

10.1101/454512 ◽

2018 ◽

Author(s):

Piret Avila ◽

Lutz Fromhage ◽

Laurent Lehmann

Keyword(s):

Resource Allocation ◽

Sexual Selection ◽

Evolutionary Biology ◽

Sex Allocation ◽

Colony Growth ◽

Eusocial Insects ◽

Dynamic Resource ◽

Colony Ontogeny ◽

Allocation Decisions ◽

Allocation Strategies

AbstractModels of sex allocation conflict are central to evolutionary biology but have mostly assumed static decisions, where resource allocation strategies are constant over colony lifespan. Here, we develop a model to study how the evolution of dynamic resource allocation strategies is affected by the queen-worker conflict in annual eusocial insects. We demonstrate that the time of dispersal of sexuals affects the sex allocation ratio through sexual selection on males. Furthermore, our model provides three predictions that depart from established results of classic static allocation models. First, we find that the queen wins the sex allocation conflict, while the workers determine the maximum colony size and colony productivity. Second, male-biased sex allocation and protandry evolve if sexuals disperse directly after eclosion. Third, when workers are more related to new queens, then the proportional investment into queens is expected to be lower, which results from the interacting effect of sexual selection (selecting for protandry) and sex allocation conflict (selecting for earlier switch to producing sexuals). Overall, we find that colony ontogeny crucially affects the outcome of sex-allocation conflict because of the evolution of distinct colony growth phases, which decouples how queens and workers affect allocation decisions and can result in asymmetric control.

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Comparison of Genotypic and Phenotypic Correlations: Cheverud’s Conjecture in Humans

10.1101/291062 ◽

2018 ◽

Author(s):

Sebastian M. Sodini ◽

Kathryn E. Kemper ◽

Naomi R. Wray ◽

Maciej Trzaskowski

Keyword(s):

Evolutionary Biology ◽

Genetic Correlations ◽

Accurate Estimation ◽

Human Populations ◽

Phenotypic Correlations ◽

Recent Developments ◽

Genotypic And Phenotypic Correlations ◽

Genetic And Phenotypic Correlations ◽

Selected Traits ◽

The Uk

AbstractAccurate estimation of genetic correlation requires large sample sizes and access to genetically informative data, which are not always available. Accordingly, phenotypic correlations are often assumed to reflect genotypic correlations in evolutionary biology. Cheverud’s conjecture asserts that the use of phenotypic correlations as proxies for genetic correlations is appropriate. Empirical evidence of the conjecture has been found across plant and animal species, with results suggesting that there is indeed a robust relationship between the two. Here, we investigate the conjecture in human populations, an analysis made possible by recent developments in availability of human genomic data and computing resources. A sample of 108,035 British European individuals from the UK Biobank was split equally into discovery and replication datasets. 17 traits were selected based on sample size, distribution and heritability. Genetic correlations were calculated using linkage disequilibrium score regression applied to the genome-wide association summary statistics of pairs of traits, and compared within and across datasets. Strong and significant correlations were found for the between-dataset comparison, suggesting that the genetic correlations from one independent sample were able to predict the phenotypic correlations from another independent sample within the same population. Designating the selected traits as morphological or non-morphological indicated little difference in correlation. The results of this study support the existence of a relationship between genetic and phenotypic correlations in humans. This finding is of specific interest in anthropological studies, which use measured phenotypic correlations to make inferences about the genetics of ancient human populations.

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Was facial width-to-height ratio subject to sexual selection pressures? A life course approach

10.1101/2020.09.24.311324 ◽

2020 ◽

Cited By ~ 1

Author(s):

Carolyn R. Hodges-Simeon ◽

Graham Albert ◽

George B. Richardson ◽

Timothy S. McHale ◽

Seth M. Weinberg ◽

...

Keyword(s):

Sex Differences ◽

Sexual Selection ◽

Current Evidence ◽

Facial Morphology ◽

Facial Growth ◽

Height Ratio ◽

Lower Face ◽

Male Adolescents ◽

Classic Pattern ◽

Facial Development

AbstractSexual selection researchers have traditionally focused on adult sex differences; however, the schedule and pattern of sex-specific ontogeny can provide insights unobtainable from an exclusive focus on adults. Recently, it has been debated whether facial width-to-height ratio (fWHR; bi-zygomatic breadth divided by midface height) is a human secondary sexual characteristic (SSC). Here, we review current evidence, then address this debate using ontogenetic evidence, which has been under-explored in fWHR research. Facial measurements collected from males and females aged 3 to 40 (Study 1; US, n=2449), and 7 to 21 (Study 2; Bolivia, n=179) were used to calculate three fWHR variants (which we call fWHRnasion, fWHRstomion, and fWHRbrow) and two other common facial masculinity ratios (facial width-to-lower-face-height ratio, fWHRlower, and cheekbone prominence). We test whether the observed pattern of facial development exhibits patterns indicative of SSCs, i.e. differential adolescent growth in either male or female facial morphology leading to an adult sex difference. Results showed that only fWHRlower exhibited both adult sex differences as well as the classic pattern of ontogeny for SSCs—greater lower-face growth in male adolescents relative to females. fWHRbrow was significantly wider among both pre- and post-pubertal males in the 2D sample; post-hoc analyses revealed that the effect was driven by large sex differences in brow height, with females having higher placed brows than males across ages. In both samples, all fWHR measures were inversely associated with age; that is, human facial growth is characterized by greater relative growth in the mid-face and lower face relative to facial width. This trend continues even into middle adulthood. BMI was also a positive predictor of most of the ratios across ages, with greater BMI associated with wider faces. Researchers collecting data on fWHR should target fWHRlower and fWHRbrow and should control for both age and BMI.

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Long-term mating positively predicts both reproductive fitness and parental investment

Journal of Biosocial Science ◽

10.1017/s0021932021000407 ◽

2021 ◽

pp. 1-12

Author(s):

Janko Međedović

Keyword(s):

Sexual Selection ◽

Reproductive Success ◽

Parental Investment ◽

Reproductive Fitness ◽

Human Populations ◽

Number Of Children ◽

Fitness Indicators ◽

Number Of Sexual Partners ◽

Sexual Selection Theory

Abstract Empirical data on the relations between mating and reproductive success are rare for humans, especially for industrial and post-industrial populations. Existing data show that mating (and especially long-term mating) can be beneficial for fitness, especially that of males. This finding is in line with the hypothesis of sexual selection operating in human populations. The present research expands on previous studies by: 1) analysing additional fitness indicators, including having children with different partners; 2) including parental investment in the analysis as another important marker of sexual selection; 3) analysing several mediators between mating, reproductive fitness and parental investment, i.e. age of first and last reproduction and desired number of children. The data were obtained in 2019 from a sample of parents living in Serbia (N=497). The findings showed that long-term mating (duration of longest partner relationship) was positively related to parental investment and number of offspring and grand-offspring. Furthermore, the link between long-term mating and reproductive success was completely mediated by the age of first reproduction and desired number of children. Short-term mating (number of sexual partners) was marginally positively related to the number of children participants had with different partners and negatively related to parental investment. No sex differences in the link between mating, fitness and parental investment were detected. In general, the signatures of sexual selection were weak in the present data, but those that were detected were in line with sexual selection theory. The present findings provide a deeper insight into the adaptive function of mating and also the mechanism of how mating is beneficial for fitness.

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