scholarly journals Sex Differences in Mortality Rates Have Increased in China Following the Single-Child Law

2011 ◽  
Vol 2 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Daniel J Kruger ◽  
Stephen P Polanski
Keyword(s):  
Sex Differences ◽  
Mortality Rates ◽  
Mortality Data ◽  
Male Mating ◽  
Mating Competition ◽  
Female Partners ◽  
Males And Females ◽  
Single Child ◽  
Male Mating Competition ◽  
Infancy And Early Childhood

Male behavior and physiology is designed for enhanced competitiveness at the expense of longevity, resulting in higher mortality rates compared to females in most species. These differences vary across populations consistent with factors indicating the intensity of male mating competition. Reproductive dynamics are strongly influenced by the relative proportions of potentially reproductive males and females in a population. Because the reproductive strategies of men and women are somewhat divergent, market influences on the intensity of mating competition and selectivity for partners produce different outcomes in female biased and male biased populations. The single-child law implemented in China in 1979 has led to increasing proportions of men in the Chinese population. Using historical mortality data, we found a trend for increasing sex differences in Chinese mortality rates from 1982 to 2000. This increase was most prevalent in young adulthood, when male mating competition is most intense as males reach sexual maturity and seek female partners. In contrast, males exhibited more survival gains than females in infancy and early childhood.

The capacity for additional matings does not affect male mating competition in the sand goby

2006 ◽  
Vol 71 (4) ◽  
pp. 865-870 ◽  
Author(s):  
Andreas Nyman ◽  
Charlotta Kvarnemo ◽  
Ola Svensson
Keyword(s):  
Male Mating ◽  
Sand Goby ◽  
Mating Competition ◽  
Male Mating Competition

scholarly journals GENETIC VARIATION AND GENETIC LOAD DUE TO THE MALE REPRODUCTIVE COMPONENT OF FITNESS IN DROSOPHILA

Genetics ◽  
1981 ◽  
Vol 97 (3-4) ◽  
pp. 719-730
Author(s):  
John G Brittnacher
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Female Choice ◽  
Genetic Load ◽  
Competition Experiment ◽  
Male Mating ◽  
Mating Competition ◽  
Mating Propensity ◽  
The Mean ◽  
Male Mating Competition

ABSTRACT The genetic variation and genetic load due to virility, the male reproductive component of fitness, was measured in Drosophila melanogaster and D. pseudoobscura using males homozygous and heterozygous for the second chromosome of each species. Virility was determined in a female-choice, male mating competition experiment where both mating propensity and fertility were taken into account.——The mean virility of the homozygous D. melanogaster males relative to the heterozygous males was 0.50; the relative mean virility of the quasinormal homozygotes was 0.56. The mean virility of the homozygous D. pseudoobscura males relative to the heterozygous males was 0.70; the relative mean virility of the nonsterile homozygotes was 0.72, and of the quasinormal homozygotes, 0.68.——Depending on the species and chromosome sampled, fertile homozygous males had a mean virility 15 to 50% lower than the mean viability of individuals homozygous for a chromosome with quasinormal viability. The genetic load due to virility was also greater than that due to the female reproductive component. This higher level of hidden genetic variation (or genetic load) indicates that the results of PROUT(1971a, b) and BUNDGAARD and CHRISTIANSEN(1972), where the virility component of fitness dominated the dynamics of an artificial polymorphism, may be more general and that virility may dominate the dynamics of natural polymorphisms as well.

scholarly journals Sex-specific and age-specific suicide mortality by method in 58 countries between 2000 and 2015

2020 ◽  
pp. injuryprev-2019-043601 ◽  
Author(s):  
Yue Wu ◽  
David C Schwebel ◽  
Yun Huang ◽  
Peishan Ning ◽  
Peixia Cheng ◽  
...  
Keyword(s):  
Negative Binomial ◽  
Age Groups ◽  
Mortality Rates ◽  
Suicide Mortality ◽  
Mortality Data ◽  
Suicide Method ◽  
Suicide Rates ◽  
Males And Females ◽  
Binomial Models ◽  
Country Specific

ObjectiveTo examine recent changes in sex-specific and age-specific suicide mortality by method across countries.MethodsUsing mortality data from the WHO mortality database, we compared sex-specific, age-specific and country-specific suicide mortality by method between 2000 and 2015. We considered seven major suicide methods: poisoning by pesticides, all other poisoning, firearms and explosives, hanging, jumping from height, drowning and other methods. Changes in suicide mortality were quantified using negative binomial models among three age groups (15–44 years, 45–64 years, and 65 years and above) for males and females separately.ResultsSuicide mortality declined substantially for both sexes and all three age groups studied in 37 of the 58 included countries between 2000 and 2015. Males consistently had much higher suicide mortality rates than females in all 58 countries. Hanging was the most common suicide method in the majority of 58 countries. Sex-specific suicide mortality varied across 58 countries significantly for all three age groups. The spectrum of suicide method generally remained stable for 28 of 58 included countries; notable changes occurred in the other 30 countries, including especially Colombia, Finland and Trinidad and Tobago.ConclusionLikely as a result of prevention efforts as well as sociodemographic changes, suicide mortality decreased substantially in 37 of the included 58 countries between 2000 and 2015. Further actions are needed to explore specific drivers of the recent changes (particularly for increases in eight countries), to understand substantial disparities in suicide rates across countries, and to develop interventions to reduce suicide rates globally.

An Evolutionary Psychological Perspective of Indirect Aggression in Girls and Women

2018 ◽  
Author(s):  
Tracy Vaillancourt ◽  
Jaimie Arona Krems
Keyword(s):  
Social Status ◽  
Physical Attractiveness ◽  
Indirect Aggression ◽  
Male Mating ◽  
Psychological Perspective ◽  
Mating Competition ◽  
Intrasexual Aggression ◽  
Male Mating Competition ◽  
To Receive ◽  
High Social Status

Although the effects of sexual selection on male mating competition and intrasexual aggression have been studied extensively for well over a century, female mating competition and intrasexual aggression have only begun to receive serious attention in recent decades. Here, we focus on one aspect of sexually selected competition in girls and women—rival derogation, which takes the form of indirect aggression. We argue that this tactic of intrasexual competition both reduces a rival’s ability to compete for desirable mates and helps aggressors achieve and maintain their own high social status. We further argue that physical attractiveness initiates the pathway leading to high social status, which is preserved through the use of indirect aggression and is associated with increased dating and sexual behavior.

scholarly journals Artificial selection reveals sex differences in the genetic basis of sexual attractiveness

2018 ◽  
Vol 115 (21) ◽  
pp. 5498-5503 ◽  
Author(s):  
Thomas P. Gosden ◽  
Adam J. Reddiex ◽  
Stephen F. Chenoweth
Keyword(s):  
Sex Differences ◽  
Sexual Selection ◽  
Female Choice ◽  
Artificial Selection ◽  
Mating Success ◽  
Male Mating ◽  
Male Choice ◽  
Trait Evolution ◽  
Males And Females ◽  
Mutual Choice

Mutual mate choice occurs when males and females base mating decisions on shared traits. Despite increased awareness, the extent to which mutual choice drives phenotypic change remains poorly understood. When preferences in both sexes target the same traits, it is unclear how evolution will proceed and whether responses to sexual selection from male choice will match or oppose responses to female choice. Answering this question is challenging, as it requires understanding, genetic relationships between the traits targeted by choice, mating success, and, ultimately, fitness for both sexes. Addressing this, we applied artificial selection to the cuticular hydrocarbons of the fly Drosophila serrata that are targeted by mutual choice and tracked evolutionary changes in males and females alongside changes in mating success. After 10 generations, significant trait evolution occurred in both sexes, but intriguingly there were major sex differences in the associated fitness consequences. Sexually selected trait evolution in males led to a genetically based increase in male mating success. By contrast, although trait evolution also occurred in females, there was no change in mating success. Our results suggest that phenotypic sexual selection on females from male choice is environmentally, rather than genetically, generated. Thus, compared with female choice, male choice is at best a weak driver of signal trait evolution in this species. Instead, the evolution of apparent female ornamentation seems more likely due to a correlated response to sexual selection on males and possibly other forms of natural selection.

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