scholarly journals Darwinian sex roles confirmed across the animal kingdom

2016 ◽  
Vol 2 (2) ◽  
pp. e1500983 ◽  
Author(s):  
Tim Janicke ◽  
Ines K. Häderer ◽  
Marc J. Lajeunesse ◽  
Nils Anthes
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Parental Care ◽  
Sex Roles ◽  
Recent Criticism ◽  
Animal Kingdom ◽  
Female Behavior ◽  
Selection Theory ◽  
Evolutionary Forces ◽  
Sexual Selection Theory

Since Darwin’s conception of sexual selection theory, scientists have struggled to identify the evolutionary forces underlying the pervasive differences between male and female behavior, morphology, and physiology. The Darwin-Bateman paradigm predicts that anisogamy imposes stronger sexual selection on males, which, in turn, drives the evolution of conventional sex roles in terms of female-biased parental care and male-biased sexual dimorphism. Although this paradigm forms the cornerstone of modern sexual selection theory, it still remains untested across the animal tree of life. This lack of evidence has promoted the rise of alternative hypotheses arguing that sex differences are entirely driven by environmental factors or chance. We demonstrate that, across the animal kingdom, sexual selection, as captured by standard Bateman metrics, is indeed stronger in males than in females and that it is evolutionarily tied to sex biases in parental care and sexual dimorphism. Our findings provide the first comprehensive evidence that Darwin’s concept of conventional sex roles is accurate and refute recent criticism of sexual selection theory.

Sexual Selection: A Very Short Introduction

2018 ◽  
Author(s):  
Marlene Zuk ◽  
Leigh W. Simmons
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Sexual Conflict ◽  
Mating Systems ◽  
Short Introduction ◽  
Selection Theory ◽  
Sexual Selection Theory ◽  
History Of ◽  
Animal World

Sexual Selection: A Very Short Introduction introduces the astounding array of behaviours and decorative traits in the animal world used for competing for mates, and considers the evolutionary logic that underpins them. It also looks at the history of our understanding of sexual selection, from Darwin’s key insights to the modern day. Considering the investment animals place on reproduction, variation in mating systems, sexual conflict, and the origin of sexual dimorphism, it discusses questions such as whether females can really choose between males on aesthetic grounds, and how sexual conflict is resolved in different species. It concludes with a consideration of the thorny question of how, and even if, sexual selection theory applies to humans.

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.

scholarly journals Variation in Chin and Mandibular Symphysis Size and Shape in Males and Females: A CT-Based Study

2020 ◽  
Vol 17 (12) ◽  
pp. 4249
Author(s):  
Tatiana Sella Tunis ◽  
Israel Hershkovitz ◽  
Hila May ◽  
Alexander Dan Vardimon ◽  
Rachel Sarig ◽  
...  
Keyword(s):  
Sexual Selection ◽  
Anatomical Landmark ◽  
Anatomical Structure ◽  
Sexually Dimorphic ◽  
Selection Theory ◽  
Size And Shape ◽  
Size Index ◽  
Sexual Selection Theory ◽  
Males And Females ◽  
Anthropological Literature

The chin is a unique anatomical landmark of modern humans. Its size and shape play an important role from the esthetic perspective. However, disagreement exists in the dental and anthropological literature regarding the sex differences in chin and symphysis morphometrics. The “sexual selection” theory is presented as a possible reason for chin formation in our species; however, many other contradictory theories also exist. This study’s aims were therefore to determine how chin and symphysis size and shape vary with sex, and to discuss “sexual selection” theory as a reason for its formation. Head and neck computed tomography (CT) scans of 419 adults were utilized to measure chin and symphysis sizes and shapes. The chin and symphysis measures were compared between the sexes using an independent-samples t-test, a Mann–Whitney test, and the F-statistic. The chin width was significantly greater in males than in females (p < 0.001), whereas the chin height, area, and size index were significantly greater in females (p < 0.001). Symphysis measures did not differ significantly between the sexes. Size accounted for 2–14% of the chin variance and between 24–33% of the symphysis variance. Overall, the chin was found to be a more heterogeneous anatomical structure than the symphysis, as well as more sexually dimorphic.

scholarly journals Reluctant males: why blue monkey males reject female sexual advances

Behaviour ◽  
2019 ◽  
Vol 157 (1) ◽  
pp. 33-58 ◽  
Author(s):  
Sofia Schembari ◽  
Marina Cords
Keyword(s):  
Sexual Selection ◽  
Social Context ◽  
Wild Population ◽  
Market Models ◽  
Selection Theory ◽  
Sexual Selection Theory ◽  
Blue Monkey ◽  
To Receive ◽  
Number Of Males

Abstract Classical sexual selection theory predicts that males should mate eagerly, yet blue monkey males often reject females’ sexual invitations. We evaluated how males’ responses to female solicitations related to female characteristics, number of males and conceptive females present, and the male’s recent copulations. Using 12 years of data from a wild population, we found that males accepted only 20% of female solicitations. Odds of acceptance (copulation) increased for conceptive females, for females with whom the male copulated recently, and when fewer males were present. Odds of accepting nulliparous females decreased when more conceptive females were available, consistent with market models. Male responses did not relate to female rank or matings with other females the same day. When males responded negatively, nulliparous females were especially likely to receive aggression vs. mere refusal. Overall, males’ decisions to mate with willing females depended both on female characteristics, especially fertility, and on social context.

scholarly journals The evolution of sexual dimorphism in parasitic cuckoos: sexual selection or coevolution?

2007 ◽  
Vol 274 (1617) ◽  
pp. 1553-1560 ◽  
Author(s):  
O Krüger ◽  
N.B Davies ◽  
M.D Sorenson
Keyword(s):  
Sexual Selection ◽  
Sexual Dimorphism ◽  
Parental Care ◽  
Brood Parasitism ◽  
Selection Pressure ◽  
Life Histories ◽  
Exceptional Case ◽  
Evolutionary Pathways ◽  
Common Situation

Sexual dimorphism is ubiquitous in animals and can result from selection pressure on one or both sexes. Sexual selection has become the predominant explanation for the evolution of sexual dimorphism, with strong selection on size-related mating success in males being the most common situation. The cuckoos (family Cuculidae) provide an exceptional case in which both sexes of many species are freed from the burden of parental care but where coevolution between parasitic cuckoos and their hosts also results in intense selection. Here, we show that size and plumage differences between the sexes in parasitic cuckoos are more likely the result of coevolution than sexual selection. While both sexes changed in size as brood parasitism evolved, we find no evidence for selection on males to become larger. Rather, our analysis indicates stronger selection on parasitic females to become smaller, resulting in a shift from dimorphism with larger females in cuckoos with parental care to dimorphism with larger males in parasitic species. In addition, the evolution of brood parasitism was associated with more cryptic plumage in both sexes, but especially in females, a result that contrasts with the strong plumage dimorphism seen in some other parasitic birds. Examination of the three independent origins of brood parasitism suggests that different parasitic cuckoo lineages followed divergent evolutionary pathways to successful brood parasitism. These results argue for the powerful role of parasite–host coevolution in shaping cuckoo life histories in general and sexual dimorphism in particular.

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