scholarly journals Women's height, reproductive success and the evolution of sexual dimorphism in modern humans

2002 ◽  
Vol 269 (1503) ◽  
pp. 1919-1923 ◽  
Author(s):  
Daniel Nettle
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Modern Humans

scholarly journals Safe sex: male–female coalitions and pre-copulatory mate-guarding in a fiddler crab

2009 ◽  
Vol 6 (2) ◽  
pp. 180-182 ◽  
Author(s):  
Richard N. C. Milner ◽  
Michael D. Jennions ◽  
Patricia R. Y. Backwell
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Observational Data ◽  
Fiddler Crab ◽  
Lower Boundary ◽  
Mate Guarding ◽  
Maintenance Costs ◽  
Boundary Maintenance ◽  
Uca Annulipes ◽  
Males And Females

In fiddler crabs both males and females defend territories that are essential for survival. Given pronounced sexual dimorphism in weaponry, how do weaponless females defend their territory from well-armed males? Using observational data and two simple experiments, we test whether male Uca annulipes protect their female neighbours from conspecific intruders. We show that males defend their female neighbours against male but not female intruders. We also show that females sometimes mate with their immediate neighbours. Male defence of female neighbours appears to represent both pre-copulatory mate-guarding and a territorial coalition. Males who ensure that their neighbour remains female could benefit through increased opportunity for future reproductive success and lower boundary maintenance costs.

Lumbar ontogenetic growth and sexual dimorphism in modern humans

2010 ◽  
Vol 22 (5) ◽  
pp. 596-603 ◽  
Author(s):  
Elías Valverde ◽  
Eloy Gálvez-López ◽  
Carmiña Alba-Fernández ◽  
Luís del Río ◽  
Adrià Casinos
Keyword(s):  
Sexual Dimorphism ◽  
Modern Humans

Sexual dimorphism in the claws of the European terrapin (Emys orbicularis): potential implications for the reproductive fitness of the species.

2019 ◽  
Author(s):  
Gonzalo Alarcos ◽  
Jaime Madrigal-González ◽  
Miguel Lizana ◽  
Fabio Flechoso
Keyword(s):  
Sexual Selection ◽  
Comparative Analysis ◽  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Sexual Maturity ◽  
Reproductive Fitness ◽  
Emys Orbicularis ◽  
Future Studies ◽  
Different Populations ◽  
Males And Females

There are many biometric differences between the males and females of the European pond turtle (Emys orbicularis) as regards their size, colouring, the shape of the plastron, tail, etc. The males use their claws to grasp the female during copulation and hence sexual selection should favour the males that have larger claws, which allow them to grasp the female better. Here, we address this type of sexual dimorphism in a comparative analysis of indices obtained from claw length, the length of the carapace and the locality where individuals were sampled. The results show that the curvature of the claws differs between the two sexes, being longer in males and increasing with age, size, and hence, the state of sexual maturity, than in females. Greater claw length could confer advantages for males when grasping the carapace of females, and hence, improve their reproductive fitness. Importance in the reproductive success that might have this feature in males could originate future studies that will relate the shape, thickness, length and other measures of the claws in males with their reproductive success in different populations, genetic variety, and most importantly, viability of populations. 

The 2nd:4th digit ratio, sexual dimorphism, population differences, and reproductive success

2000 ◽  
Vol 21 (3) ◽  
pp. 163-183 ◽  
Author(s):  
J.T. Manning ◽  
L. Barley ◽  
J. Walton ◽  
D.I. Lewis-Jones ◽  
R.L. Trivers ◽  
...  
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Digit Ratio ◽  
Population Differences

scholarly journals Sexual dimorphism in Australopithecus afarensis was similar to that of modern humans

2003 ◽  
Vol 100 (16) ◽  
pp. 9404-9409 ◽  
Author(s):  
P. L. Reno ◽  
R. S. Meindl ◽  
M. A. McCollum ◽  
C. O. Lovejoy
Keyword(s):  
Sexual Dimorphism ◽  
Australopithecus Afarensis ◽  
Modern Humans

scholarly journals Mating enhances immune function of Drosophila melanogaster populations against bacterial pathogens

2019 ◽  
Author(s):  
Nitin Bansal ◽  
Biswajit Shit ◽  
Aparajita ◽  
Tejashwini Hegde ◽  
Rochishnu Dutta ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Immune Function ◽  
Sexual Activity ◽  
Bacterial Infections ◽  
Bacterial Pathogens ◽  
Relative Cost ◽  
Trade Off ◽  
Darwinian Fitness

AbstractImmunity and reproduction are two important processes that affect fitness of an organisms. Sexual activity has been previously shown to determine the degree to which a population is able to survive various infections. While many studies have demonstrated a trade-off between immune function and reproduction, many studies have found synergistic relation between the two fitness determinants. Besides it is generally hypothesised that sexes may differ in immunity due to relative cost they incur during reproduction with males losing in immunity to rather increase their reproductive success. In this study, we test the effect of immune function on the survival of mated and virgin replicates of a large outbred baseline D. melanogaster population that was infected with four different bacterial infections. We find enhanced survival in mated flies than virgin flies in response to all four bacterial infections across all replicates. While investigating sexual dimorphism in immune function, we find no difference in sexes in their ability to survive the imposed bacterial infections. Synergistic interaction between reproduction and immunity may exist if it improves Darwinian fitness of either sexes of a population under selection, and are not necessarily limited by each other due to trade-off over finite resources.

scholarly journals A morphometric analysis of hominin teeth attributed to Australopithecus, Paranthropus and Homo

2016 ◽  
Vol Volume 112 (Number 11/12) ◽  
Author(s):  
Susan J. Dykes ◽  
Keyword(s):  
Sexual Dimorphism ◽  
Critical Role ◽  
Modern Human ◽  
Common Element ◽  
Female Group ◽  
Modern Humans ◽  
Extant Species ◽  
Tribal Populations ◽  
Fossil Hominin ◽  
Species Variability

Abstract Teeth are the most common element in the fossil record and play a critical role in taxonomic assessments. Variability in extant hominoid species is commonly used as a basis to gauge expected ranges of variability in fossil hominin species. In this study, variability in lower first molars is visualised in morphospace for four extant hominoid species and seven fossil hominin species. A size-versus-shape-based principle component analysis plot was used to recognise spatial patterns applicable to sexual dimorphism in extant species for comparison with fossil hominin species. In three African great ape species, variability occurs predominantly according to size (rather than shape), with the gorilla sample further separating into a male and a female group according to size. A different pattern is apparent for the modern human sample, in which shape variability is more evident. There is overlap between male and female modern humans and some evidence of grouping by linguistic/tribal populations. When fossil hominin species are analysed using equivalent axes of variance, the specimens group around species holotypes in quite similar patterns to those of the extant African great apes, but six individual fossil molars fall well outside of polygons circumscribing holotype clusters; at least three of these specimens are of interest for discussion in the context of sexual dimorphism, species variability and current species classifications. An implication of this study is that, especially in the case of modern humans, great caution needs to be exercised in using extant species as analogues for assessing variability considered to be a result of sexual dimorphism in fossil hominin species.

scholarly journals Voice pitch predicts reproductive success in male hunter-gatherers

2007 ◽  
Vol 3 (6) ◽  
pp. 682-684 ◽  
Author(s):  
C.L Apicella ◽  
D.R Feinberg ◽  
F.W Marlowe
Keyword(s):  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Child Mortality ◽  
Birth Control ◽  
Selection Pressure ◽  
Sexually Dimorphic ◽  
Control Methods ◽  
Voice Pitch ◽  
Hunter Gatherers ◽  
Number Of Children

The validity of evolutionary explanations of vocal sexual dimorphism hinges upon whether or not individuals with more sexually dimorphic voices have higher reproductive success than individuals with less dimorphic voices. However, due to modern birth control methods, these data are rarely described, and mating success is often used as a second-rate proxy. Here, we test whether voice pitch predicts reproductive success, number of children born and child mortality in an evolutionarily relevant population of hunter-gatherers. While we find that voice pitch is not related to reproductive outcomes in women, we find that men with low voice pitch have higher reproductive success and more children born to them. However, voice pitch in men does not predict child mortality. These findings suggest that the association between voice pitch and reproductive success in men is mediated by differential access to fecund women. Furthermore, they show that there is currently selection pressure for low-pitch voices in men.

scholarly journals Ornaments are equally informative in males and females: a bivariate meta-analysis in birds

2021 ◽  
Author(s):  
Sergio Nolazco ◽  
Kaspar Delhey ◽  
Shinichi Nakagawa ◽  
Anne Peters
Keyword(s):  
Systematic Review ◽  
Sexual Dimorphism ◽  
Reproductive Success ◽  
Meta Analysis ◽  
Large Dataset ◽  
Female Ornament ◽  
Female Ornaments ◽  
Similar Information ◽  
Males And Females ◽  
Male Ornaments

Abstract Female ornaments are often reduced, male-like traits. Although these were long perceived as nonadaptive, it is now broadly accepted that female ornaments can be functional. However, it is unclear whether this is as common in females as it is in males, and whether ornaments fulfil similar signalling roles. To test this, we conduct a systematic review and apply a phylogenetically controlled bivariate meta-analysis to a large dataset of ornaments in mutually ornamented birds. As expected, female ornament expression tends to be reduced compared to males. However, ornaments are equally strongly associated with indicators of body condition and aspects of reproductive success in both sexes, regardless of the degree of sexual dimorphism. Thus, ornaments in birds provide similar information in both sexes: more ornamented individuals are in better condition and achieve higher reproductive success. Although limited by their correlational nature, these outcomes imply that female ornaments could widely function in a similar manner as male ornaments.

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