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Philosophical Transactions of the Royal... Dec 2020The past half century has seen the development of the field of post-ejaculatory sexual selection, the sequel to sexual selection for mate-acquisition (pre-ejaculatory)... (Review)
Review
The past half century has seen the development of the field of post-ejaculatory sexual selection, the sequel to sexual selection for mate-acquisition (pre-ejaculatory) described by Darwin. In richness and diversity of adaptations, post-ejaculatory selection rivals that of pre-ejaculatory sexual selection. Anisogamy-and hence two sexes-likely arose by primeval gamete competition, and sperm competition remains a major force maintaining high sperm numbers. The post-ejaculatory equivalent of male-male competition for matings, sperm competition was an intense ancestral form of sexual selection, typically weakening as mobility and internal fertilization developed in many taxa, when some expenditure became diverted into pre-ejaculatory competition. Sperm competition theory has been relatively successful in explaining variation in relative testes size and sperm numbers per ejaculate and is becoming more successful in explaining variation in sperm phenotype. Sperm competition has generated many other male adaptations such as seminal fluid proteins that variously modify female reproduction towards male interests, and copulatory plugs, prolonged copulations and post-ejaculatory guarding behaviour that reduce female remating probability, many of which result in sexual conflict. This short survey of conceptual developments is intended as a broad overview, mainly as a primer for new researchers. This article is part of the theme issue 'Fifty years of sperm competition'.
Topics: Animals; Male; Reproduction; Sexual Behavior, Animal; Spermatozoa
PubMed: 33070727
DOI: 10.1098/rstb.2020.0061 -
The British Journal of General Practice... Feb 2010
Topics: Circumcision, Male; Humans; Islam; Male
PubMed: 20132715
DOI: 10.3399/bjgp10X483283 -
Trends in Ecology & Evolution Jul 2014A popular notion in sexual selection is that females are polyandrous and their offspring are commonly sired by more than a single male. We now have large-scale evidence... (Review)
Review
A popular notion in sexual selection is that females are polyandrous and their offspring are commonly sired by more than a single male. We now have large-scale evidence from natural populations to be able to verify this assumption. Although we concur that polyandry is a generally common and ubiquitous phenomenon, we emphasise that it remains variable. In particular, the persistence of single paternity, both within and between populations, requires more careful consideration. We also explore an intriguing relation of polyandry with latitude. Several recent large-scale analyses of the relations between key population fitness variables, such as heterozygosity, effective population size (Ne), and inbreeding coefficients, make it possible to examine the global effects of polyandry on population fitness for the first time.
Topics: Animals; Female; Genetic Fitness; Geography; Male; Sexual Behavior, Animal
PubMed: 24831458
DOI: 10.1016/j.tree.2014.04.005 -
Ecology Letters May 2022Male mate choice occurs in several animal species, but we know little about the factors that influence the expression of this behaviour. Males vary in their capacity to... (Meta-Analysis)
Meta-Analysis Review
Male mate choice occurs in several animal species, but we know little about the factors that influence the expression of this behaviour. Males vary in their capacity to acquire mates (i.e. male quality), which could be crucial to male mate choice expression but it is often overlooked. Using a meta-analytical approach, we explore interindividual variation in the expression of male mate choice by comparing the mating investment of males of different qualities and phenotypes to high- and low-quality females. We used two datasets that together contained information from 60 empirical studies, comprising 52 species. We found that males of all qualities and phenotypes prefer high-quality females, but differ in the strength of such preference. High- and medium-quality males are choosier than low-quality males. Similarly, males that are larger or in greater body condition are choosier than their counterparts. In contrast, male body mass and age are not associated with changes in male mate choice. We also show that experimental design may influence our understanding of male mating investment patterns, which may limit the generalisation of our findings. Nonetheless, we argue that male quality may be an important feature in the expression of male mate choice.
Topics: Animals; Female; Male; Mating Preference, Animal; Phenotype; Reproduction; Sexual Behavior, Animal
PubMed: 35259282
DOI: 10.1111/ele.13981 -
Asian Journal of Andrology 2020
Topics: Genitalia, Male; Humans; Male; Plastic Surgery Procedures
PubMed: 32098933
DOI: 10.4103/aja.aja_147_19 -
Fertility and Sterility May 2018
Topics: Fertility; Humans; Male; Semen Analysis
PubMed: 29680314
DOI: 10.1016/j.fertnstert.2018.03.001 -
Journal of Theoretical Biology Jan 2022In some species of separate sexes, males present a nuptial gift containing nutrition to their mate. Producing a large nuptial gift is a considerable cost to the male,...
In some species of separate sexes, males present a nuptial gift containing nutrition to their mate. Producing a large nuptial gift is a considerable cost to the male, but it may improve his siring success if the female reduces the likelihood to accept another male after receiving a large gift. The female may receive a direct benefit by accepting another male who provides an additional nuptial gift. Additionally, the female may receive an indirect fitness benefit via laying offspring sired by a male who is able to produce a large nuptial gift. We formalized the multivariate quantitative genetics model describing the coevolution of the size of nuptial gift produced by the male (x) and the female's propensity to engage in remating (y). We analyzed the model focusing two cases: [1] remating females receive no indirect fitness benefit, but enjoy direct benefit of nutrition; and [2] remating females receive no direct benefit, but enjoy an indirect fitness benefit due to a positive genetic correlation of x and y, which is possible if random mutations tend to make males produce small nuptial gifts. In both cases, the stable evolutionary equilibrium with neither nuptial gift nor remating (x-=y-=0) always exists. Another stable equilibrium may exist in which male produces nuptial gifts (x->0) and female engage in multiple mating (y->0). We discussed implications to the sexual conflict.
Topics: Animals; Female; Male; Models, Genetic; Reproduction; Sexual Behavior, Animal
PubMed: 34688613
DOI: 10.1016/j.jtbi.2021.110939 -
Canadian Medical Association Journal Nov 1973
Topics: Humans; Male; Vasectomy
PubMed: 4750294
DOI: No ID Found -
Proceedings of the Royal Society of... Apr 1953
Topics: Disorders of Sex Development; Humans; Male
PubMed: 13055900
DOI: No ID Found -
British Medical Journal Oct 1952
Topics: Circumcision, Male; Criminals; Foreskin; Humans; Male
PubMed: 12978321
DOI: No ID Found