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

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

Biology Letters ◽

10.1098/rsbl.2009.0767 ◽

2009 ◽

Vol 6 (2) ◽

pp. 180-182 ◽

Cited By ~ 15

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.

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Application of Three Dimensional Geometric Morphometric Analysis for Sexual Dimorphism of Human Skull: A Systematic Review

IIUM Medical Journal Malaysia ◽

10.31436/imjm.v18i1.214 ◽

2020 ◽

Vol 18 (1) ◽

Author(s):

Abdelnasser Ibrahim ◽

Aspalilah Alias ◽

Mohamed Swarhib Shafie ◽

Faridah Mohd Nor

Keyword(s):

Systematic Review ◽

Sexual Dimorphism ◽

Morphometric Analysis ◽

Meta Analysis ◽

Positive Contribution ◽

Inclusion Criteria ◽

Geometric Morphometric ◽

Human Skull ◽

Geometric Morphometric Analysis

The present systematic review explores the most sexually dimorphic parameters by using geometric morphometric analysis of human skull. An extended search was conducted in Google Scholars and PubMed (published between 2005 and 2017). The main inclusion criteria were research articles published in English, and studies that used geometric morphometric analysis for classification of human skull. The literature search identified 54 potential relevant articles whereby, five had met the inclusion criteria. Most studies reported positive contribution of geometric morphometric as an alternative and accurate tool for classification of unknown human crania. Geometric morphometric method resulted in a high classification accuracy of sexual dimorphism among different populations. Further studies are required to approach the best method used for varied types of postcranial bones equipped with a more advanced meta-analysis of the results.

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The weak evidence of lip print analysis for sexual dimorphism in forensic dentistry: a systematic literature review and meta-analysis

Scientific Reports ◽

10.1038/s41598-021-03680-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Ademir Franco ◽

Lorenna Keren Gomes Lima ◽

Murilo Navarro de Oliveira ◽

Walbert de Andrade Vieira ◽

Cauane Blumenberg ◽

...

Keyword(s):

Sexual Dimorphism ◽

Literature Review ◽

Diagnostic Accuracy ◽

Random Effects ◽

Systematic Literature Review ◽

Meta Analysis ◽

Grey Literature ◽

Risk Of Bias ◽

Forensic Dentistry ◽

Males And Females

AbstractThis study aimed to assess the prevalence of lip print patterns among males and females, and to test the diagnostic accuracy of lip pattern analysis for sexual dimorphism in forensic dentistry. A systematic literature review was performed following the PRISMA guidelines. The search was performed in six primary databases and three databases to cover part of the grey literature. Observational and diagnostic accuracy studies that investigated lip print patterns through cheiloscopy for sexual dimorphism were selected. Risk of bias was assessed with the Joanna Briggs Institute (JBI) tool. Proportion meta-analysis using random effects was fitted to pool the accuracy of cheiloscopy. The odds of correctly identifying males and females was assessed through a random effects meta-analysis. GRADE approach was used to assess certainty of evidence. The search found 3,977 records, published between 1982 and 2019. Seventy-two studies fulfilled the eligibility criteria and were included in the qualitative analysis (n = 22,965 participants), and twenty-two studies were sampled for meta-analysis. Fifty studies had low risk of bias. Suzuki and Tsuchihashi’s technique was the most prevalent among studies. The accuracy of sexual dimorphism through cheiloscopy ranged between 52.7 and 93.5%, while the pooled accuracy was 76.8% (95% CI = 65.8; 87.7). There was no difference between the accuracy to identify males or females (OR = 0.71; 95% CI = 0.26; 1.99). The large spectrum of studies on sexual dimorphism via cheiloscopy depicted accuracy percentage rates that rise uncertainty and concern. The unclear performance of the technique could lead to wrong forensic practice.

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

Basic and Applied Herpetology ◽

10.11160/bah.91 ◽

2019 ◽

Cited By ~ 1

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.

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