scholarly journals Variance in male reproductive success and sexual size dimorphism in pinnipeds: testing an assumption of sexual selection theory

Mammal Review ◽  
2013 ◽  
Vol 44 (2) ◽  
pp. 88-93 ◽  
Author(s):  
Manuela González-Suárez ◽  
Marcelo H. Cassini
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Sexual Size Dimorphism ◽  
Male Reproductive Success ◽  
Size Dimorphism ◽  
Selection Theory ◽  
Sexual Selection Theory

Mating Strategy and Reproductive Success in the Teiid Lizard, Ameiva Plei

Behaviour ◽  
1995 ◽  
Vol 132 (7-8) ◽  
pp. 529-557 ◽  
Author(s):  
Ellen J. Censky
Keyword(s):  
Sexual Selection ◽  
Natural Selection ◽  
Reproductive Success ◽  
Sexual Size Dimorphism ◽  
Size Dimorphism ◽  
Large Size ◽  
Trade Offs ◽  
Males And Females ◽  
Current Selection ◽  
Growth And Reproduction

AbstractCurrent selection on sexual size dimorphism was studied in a widely foraging non-territorial lizard, Ameiva plei. Males were significantly larger than females. Large males won intrasexual agonistic encounters and guarded females during their entire receptive period (1-4 days). Guarding males spent significantly less time foraging than males who were alone. Only males that guarded females were observed to mate. Mating success was highly skewed with only six of 21 mature males in the study site observed mating. All six males who mated were 141 mm SVL (males mature at 62 mm SVL). The four largest males obtained 84% of all observed matings and were estimated to have fertilized 88% of the eggs. Sexual selection appears to favor large size in males due to competition among males to guard females. Large females on Anguilla also had higher reproductive success bccause SVL was positively correlated with clutch size and number of clutches in a season. It appears that natural selection has favored different trade-offs between growth and reproduction in males and females.

Latitudinal clines in sexual selection, sexual size dimorphism, and sex‐specific genetic dispersal during a poleward range expansion

2021 ◽  
Author(s):  
Rachael Y. Dudaniec ◽  
Alexander R. Carey ◽  
Erik I. Svensson ◽  
Bengt Hansson ◽  
Chuan Ji Yong ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Range Expansion ◽  
Sexual Size Dimorphism ◽  
Size Dimorphism ◽  
Latitudinal Clines

scholarly journals Darwin's bawdy: the popular, gendered and radical reception of the Descent of Man in the US, 1871–1910

BJHS Themes ◽  
2021 ◽  
pp. 1-17
Author(s):  
Kimberly A. Hamlin
Keyword(s):  
Sexual Selection ◽  
Selection Theory ◽  
Scientific Establishment ◽  
Scientific Institutions ◽  
The Us ◽  
Sexual Selection Theory ◽  
Descent Of Man

Abstract Most studies of the American reception of Darwin have focused on the Origin. The Descent of Man, however, was even more widely read and discussed, especially by those outside the emerging scientific establishment. This essay maps the varied, popular and radical responses to the Descent and suggests that these unauthorized readers helped shape the formation of American scientific institutions (by encouraging scientists to close ranks), as well as ordinary Americans’ perceptions of gender and sex. I argue that the radical – freethinkers, socialists and feminists – embrace of sexual selection theory provides one explanation for naturalists’ scepticism of the theory.

More sires may enhance offspring fitness in Northern Map Turtles (Graptemys geographica)

2013 ◽  
Vol 91 (8) ◽  
pp. 581-588 ◽  
Author(s):  
Nicola Banger ◽  
Gabriel Blouin-Demers ◽  
Grégory Bulté ◽  
Stephen C. Lougheed
Keyword(s):  
Sexual Selection ◽  
Reproductive Success ◽  
Hatching Success ◽  
Locomotor Performance ◽  
Conservative Estimate ◽  
Genetic Quality ◽  
Offspring Fitness ◽  
Sexual Selection Theory ◽  
Map Turtles ◽  
Graptemys Geographica

Sexual selection theory predicts that males should be promiscuous to maximize their reproductive success, while females should be choosy. Yet females of many taxa often produce progeny sired by multiple males, indicating that promiscuity can be important for the reproductive success of females. Promiscuity may enhance the fitness of females if it increases the genetic quality, or the genetic variety, and thus the viability of their offspring. We quantified the number of sires per clutch in a population of Northern Map Turtles (Graptemys geographica (LeSueur, 1817)) in Lake Opinicon, Ontario, Canada, and tested whether the number of sires affects several metrics of viability in hatchlings. Based on the most conservative estimate, at least 71% of clutches in this population are sired by multiple males, but there was no evidence that larger clutches are sired by more males. Clutches sired by more males had higher hatching success and survival, but the differences were not statistically significant. We did not find any effect of the number of sires on hatchling morphology or locomotor performance. Collectively, our results partially support the hypothesis that promiscuity can increase the reproductive success of female Northern Map Turtles.

scholarly journals Sexual selection and sexual size dimorphism in animals

2021 ◽  
Vol 17 (9) ◽  
pp. 20210251
Author(s):  
Tim Janicke ◽  
Salomé Fromonteil
Keyword(s):  
Sexual Selection ◽  
Sex Difference ◽  
Positive Relationship ◽  
Sexual Size Dimorphism ◽  
Effect Sizes ◽  
Size Dimorphism ◽  
Bateman Gradient ◽  
Mixed Support ◽  
Evolutionary Force ◽  
Length Measurements

Sexual selection is often considered as a critical evolutionary force promoting sexual size dimorphism (SSD) in animals. However, empirical evidence for a positive relationship between sexual selection on males and male-biased SSD received mixed support depending on the studied taxonomic group and on the method used to quantify sexual selection. Here, we present a meta-analytic approach accounting for phylogenetic non-independence to test how standardized metrics of the opportunity and strength of pre-copulatory sexual selection relate to SSD across a broad range of animal taxa comprising up to 95 effect sizes from 59 species. We found that SSD based on length measurements was correlated with the sex difference in the opportunity for sexual selection but showed a weak and statistically non-significant relationship with the sex difference in the Bateman gradient. These findings suggest that pre-copulatory sexual selection plays a limited role for the evolution of SSD in a broad phylogenetic context.

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