ZoologyReproductive Biology and Phylogeny of Fishes (Agnathans and Bony Fishes): Sperm Competition, Hormones, Sexual Selection, Reproductive Modes, Fertilization, Sex Determination, Parental Care, Conservation, Cryopreservation, Embryology, Genetics. Reproductive Biology and Phylogeny, Volume 8B. Edited by Barrie G. M.Jamieson. Enfield (New Hampshire): Science Publishers. $139.50. xii  540 p.; ill.; index. 9781578085811 (Volume 8B); 9781578082711 (series). 2009.

‘Sperm competition’—where ejaculates from two or more males compete for fertilization—and ‘cryptic female choice’—where females bias this contest to suit their reproductive interests—are now part of the everyday lexicon of sexual selection. Yet the physiological processes that underlie these post-ejaculatory episodes of sexual selection remain largely enigmatic. In this review, we focus on a range of post-ejaculatory cellular- and molecular-level processes, known to be fundamental for fertilization across most (if not all) sexually reproducing species, and point to their putative role in facilitating sexual selection at the level of the cells and gametes, called ‘gamete-mediated mate choice’ (GMMC). In this way, we collate accumulated evidence for GMMC across different mating systems, and emphasize the evolutionary significance of such non-random interactions among gametes. Our overall aim in this review is to build a more inclusive view of sexual selection by showing that mate choice often acts in more nuanced ways than has traditionally been assumed. We also aim to bridge the conceptual divide between proximal mechanisms of reproduction, and adaptive explanations for patterns of non-random sperm–egg interactions that are emerging across an increasingly diverse array of taxa.

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Sexual selection favours male parental care, when females can choose

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2011.2237 ◽

2011 ◽

Vol 279 (1734) ◽

pp. 1784-1790 ◽

Cited By ~ 54

Author(s):

Suzanne H. Alonzo

Keyword(s):

Sexual Selection ◽

Parental Care ◽

Female Choice ◽

Mating Success ◽

Current Theory ◽

Sharp Contrast ◽

Recent Theory ◽

Extra Pair Paternity ◽

Female Promiscuity ◽

Male Care

Explaining the evolution of male care has proved difficult. Recent theory predicts that female promiscuity and sexual selection on males inherently disfavour male care. In sharp contrast to these expectations, male-only care is often found in species with high extra-pair paternity and striking variation in mating success, where current theory predicts female-only care. Using a model that examines the coevolution of male care, female care and female choice; I show that inter-sexual selection can drive the evolution of male care when females are able to bias mating or paternity towards parental males. Surprisingly, female choice for parental males allows male care to evolve despite low relatedness between the male and the offspring in his care. These results imply that predicting how sexual selection affects parental care evolution will require further understanding of why females, in many species, either do not prefer or cannot favour males that provide care.

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Post-Copulatory Sexual Selection

Evolutionary Biology ◽

10.1093/obo/9780199941728-0131 ◽

2021 ◽

Author(s):

Patricia L.R. Brennan ◽

Dara N. Orbach

Keyword(s):

Sexual Selection ◽

Sperm Competition ◽

Female Choice ◽

Reproductive Tract ◽

Seminal Fluid ◽

Fertilization Success ◽

Female Reproductive Tract ◽

Cryptic Female Choice ◽

Trade Offs ◽

Morphological Criteria

The field of post-copulatory sexual selection investigates how female and male adaptations have evolved to influence the fertilization of eggs while optimizing fitness during and after copulation, when females mate with multiple males. When females are polyandrous (one female mates with multiple males), they may optimize their mating rate and control the outcome of mating interactions to acquire direct and indirect benefits. Polyandry may also favor the evolution of male traits that offer an advantage in post-copulatory male-male sperm competition. Sperm competition occurs when the sperm, seminal fluid, and/or genitalia of one male directly impacts the outcome of fertilization success of a rival male. When a female mates with multiple males, she may use information from a number of traits to choose who will sire her offspring. This cryptic female choice (CFC) to bias paternity can be based on behavioral, physiological, and morphological criteria (e.g., copulatory courtship, volume and/or composition of seminal fluid, shape of grasping appendages). Because male fitness interests are rarely perfectly aligned with female fitness interests, sexual conflict over mating and fertilization commonly occur during copulatory and post-copulatory interactions. Post-copulatory interactions inherently involve close associations between female and male reproductive characteristics, which in many species potentially include sperm storage and sperm movement inside the female reproductive tract, and highlight the intricate coevolution between the sexes. This coevolution is also common in genital morphology. The great diversity of genitalia among species is attributed to sexual selection. The evolution of genital attributes that allow females to maintain reproductive autonomy over paternity via cryptic female choice or that prevent male manipulation and sexual control via sexually antagonistic coevolution have been well documented. Additionally, cases where genitalia evolve through intrasexual competition are well known. Another important area of study in post-copulatory sexual selection is the examination of trade-offs between investments in pre-copulatory and post-copulatory traits, since organisms have limited energetic resources to allocate to reproduction, and securing both mating and fertilization is essential for reproductive success.

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Evolutionary insight from a humble fly: sperm competition and the yellow dungfly

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2020.0062 ◽

2020 ◽

Vol 375 (1813) ◽

pp. 20200062

Author(s):

Leigh W. Simmons ◽

Geoff A. Parker ◽

David J. Hosken

Keyword(s):

Sexual Selection ◽

Sperm Competition ◽

Paradigm Shift ◽

Mate Guarding ◽

Reproductive Behaviour ◽

Costs And Benefits ◽

Theme Issue ◽

Male And Female ◽

Sexual Selection Theory ◽

The 1960S

Studies of the yellow dungfly in the 1960s provided one of the first quantitative demonstrations of the costs and benefits associated with male and female reproductive behaviour. These studies advanced appreciation of sexual selection as a significant evolutionary mechanism and contributed to the 1970s paradigm shift toward individual selectionist thinking. Three behaviours in particular led to the realization that sexual selection can continue during and after mating: (i) female receptivity to remating, (ii) sperm displacement and (iii) post-copulatory mate guarding. These behaviours either generate, or are adaptations to sperm competition, cryptic female choice and sexual conflict. Here we review this body of work, and its contribution to the development of post-copulatory sexual selection theory. This article is part of the theme issue ‘Fifty years of sperm competition’.

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Sperm removal during copulation confirmed in the oldest extant damselfly,Hemiphlebia mirabilis

PeerJ ◽

10.7717/peerj.2077 ◽

2016 ◽

Vol 4 ◽

pp. e2077 ◽

Cited By ~ 7

Author(s):

Adolfo Cordero-Rivera

Keyword(s):

Sexual Selection ◽

Sperm Competition ◽

Short Range ◽

Body Position ◽

Reproductive Behaviour ◽

Scramble Competition ◽

Stage I ◽

Female Genitalia ◽

Second Stage ◽

Male Genital

Postcopulatory sexual selection may favour mechanisms to reduce sperm competition, like physical sperm removal by males. To investigate the origin of sperm removal, I studied the reproductive behaviour and mechanisms of sperm competition in the only living member of the oldest damselfly family,Hemiphlebia mirabilis, one species that was considered extinct in the 1980s. This species displays scramble competition behaviour. Males search for females with short flights and both sexes exhibit a conspicuous “abdominal flicking”. This behaviour is used by males during an elaborate precopulatory courtship, unique among Odonata. Females use a similar display to reject male attempts to form tandem, but eventually signal receptivity by a particular body position. Males immobilise females during courtship using their legs, which, contrarily to other damselflies, never autotomise. Copulation is short (range 4.1–18.7 min), and occurs in two sequential stages. In the first stage, males remove part of the stored sperm, and inseminate during the second stage, at the end of mating. The male genital ligula matches the size and form of female genitalia, and ends by two horns covered by back-oriented spines. The volume of sperm in females before copulation was 2.7 times larger than the volume stored in females whose copulation was interrupted at the end of stage I, indicative of a significant sperm removal. These results point out that sperm removal is an old character in the evolution of odonates, possibly dating back to the Permian.

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