Sexual selection

Last updated

Sexual selection creates colourful differences between sexes in Goldie's bird-of-paradise. Male above; female below. Painting by John Gerrard Keulemans. Paradesia decora Keulemans.jpg
Sexual selection creates colourful differences between sexes in Goldie's bird-of-paradise. Male above; female below. Painting by John Gerrard Keulemans.

Sexual selection is a mechanism of evolution in which members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection). These two forms of selection mean that some individuals have greater reproductive success than others within a population, for example because they are more attractive or prefer more attractive partners to produce offspring. Successful males benefit from frequent mating and monopolizing access to one or more fertile females. Females can maximise the return on the energy they invest in reproduction by selecting and mating with the best males.

Contents

The concept was first articulated by Charles Darwin who wrote of a "second agency" other than natural selection, in which competition between mate candidates could lead to speciation. The theory was given a mathematical basis by Ronald Fisher in the early 20th century. Sexual selection can lead males to extreme efforts to demonstrate their fitness to be chosen by females, producing sexual dimorphism in secondary sexual characteristics, such as the ornate plumage of birds-of-paradise and peafowl, or the antlers of deer. Depending on the species, these rules can be reversed. This is caused by a positive feedback mechanism known as a Fisherian runaway, where the passing-on of the desire for a trait in one sex is as important as having the trait in the other sex in producing the runaway effect. Although the sexy son hypothesis indicates that females would prefer male offspring, Fisher's principle explains why the sex ratio is most often 1:1. Sexual selection is widely distributed in the animal kingdom, and is also found in plants and fungi.

History

Darwin

Victorian cartoonists mocked Darwin's ideas about display in sexual selection. Here he is fascinated by the apparent steatopygia in the latest fashion. Darwin sexual caricature.gif
Victorian cartoonists mocked Darwin's ideas about display in sexual selection. Here he is fascinated by the apparent steatopygia in the latest fashion.

Sexual selection was first proposed by Charles Darwin in On the Origin of Species (1859) and developed in The Descent of Man, and Selection in Relation to Sex (1871), as he felt that natural selection alone was unable to account for certain types of non-survival adaptations. He once wrote to a colleague that "The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick!" His work divided sexual selection into male–male competition and female choice. [1] [2]

... depends, not on a struggle for existence, but on a struggle between the males for possession of the females; the result is not death to the unsuccessful competitor, but few or no offspring. [3]

... when the males and females of any animal have the same general habits ... but differ in structure, colour, or ornament, such differences have been mainly caused by sexual selection. [4]

These views were to some extent opposed by Alfred Russel Wallace, mostly after Darwin's death. He accepted that sexual selection could occur, but argued that it was a relatively weak form of selection. He argued that male–male competitions were forms of natural selection, but that the "drab" peahen's coloration is itself adaptive as camouflage. In his opinion, ascribing mate choice to females was attributing the ability to judge standards of beauty to animals (such as beetles) far too cognitively undeveloped to be capable of aesthetic feeling. [5]

Sexual selection protected flour beetles from extinction in a ten-year experiment. Tribolium castaneum87-300.jpg
Sexual selection protected flour beetles from extinction in a ten-year experiment.

Darwin's ideas on sexual selection were met with scepticism by his contemporaries and not considered of great importance, until in the 1930s biologists decided to include sexual selection as a mode of natural selection. [7] Only in the 21st century have they become more important in biology; the theory is now seen as generally applicable and analogous to natural selection. [8] A ten-year study, experimentally varying sexual selection on flour beetles with other factors held constant, showed that sexual selection protected even an inbred population against extinction. [6]

Fisherian runaway

Ronald Fisher, the English statistician and evolutionary biologist, developed his ideas about sexual selection in his 1930 book The Genetical Theory of Natural Selection . These include the sexy son hypothesis, which might suggest a preference for male offspring, and Fisher's principle, which explains why the sex ratio is usually close to 1:1. The Fisherian runaway describes how sexual selection accelerates the preference for a specific ornament, causing the preferred trait and female preference for it to increase together in a positive feedback runaway cycle. [9] He remarked that: [10]

... plumage development in the male, and sexual preference for such developments in the female, must thus advance together, and so long as the process is unchecked by severe counterselection, will advance with ever-increasing speed. In the total absence of such checks, it is easy to see that the speed of development will be proportional to the development already attained, which will therefore increase with time exponentially, or in geometric progression. —Ronald Fisher, 1930 [9]

Male long-tailed widowbird Euplectes progne male South Africa cropped.jpg
Male long-tailed widowbird

This causes a dramatic increase in both the male's conspicuous feature and in female preference for it, resulting in marked sexual dimorphism, until practical physical constraints halt further exaggeration. A positive feedback loop is created, producing extravagant physical structures in the non-limiting sex. A classic example of female choice and potential runaway selection is the long-tailed widowbird. While males have long tails that are selected for by female choice, female tastes in tail length are still more extreme with females being attracted to tails longer than those that naturally occur. [11] Fisher understood that female preference for long tails may be passed on genetically, in conjunction with genes for the long tail itself. Long-tailed widowbird offspring of both sexes inherit both sets of genes, with females expressing their genetic preference for long tails, and males showing off the coveted long tail itself. [10]

Richard Dawkins presents a non-mathematical explanation of the runaway sexual selection process in his book The Blind Watchmaker . [10] Females that prefer long tailed males tend to have mothers that chose long-tailed fathers. As a result, they carry both sets of genes in their bodies. That is, genes for long tails and for preferring long tails become linked. The taste for long tails and tail length itself may therefore become correlated, tending to increase together. The more tails lengthen, the more long tails are desired. Any slight initial imbalance between taste and tails may set off an explosion in tail lengths. Fisher wrote that:

The exponential element, which is the kernel of the thing, arises from the rate of change in hen taste being proportional to the absolute average degree of taste. —Ronald Fisher, 1932 [12]

The peacock tail in flight, the proposed classic example of a Fisherian runaway Peacock Flying.jpg
The peacock tail in flight, the proposed classic example of a Fisherian runaway

The female widowbird chooses to mate with the most attractive long-tailed male so that her progeny, if male, will themselves be attractive to females of the next generation—thereby fathering many offspring that carry the female's genes. Since the rate of change in preference is proportional to the average taste amongst females, and as females desire to secure the services of the most sexually attractive males, an additive effect is created that, if unchecked, can yield exponential increases in a given taste and in the corresponding desired sexual attribute. [10]

It is important to notice that the conditions of relative stability brought about by these or other means, will be far longer duration than the process in which the ornaments are evolved. In most existing species the runaway process must have been already checked, and we should expect that the more extraordinary developments of sexual plumage are not due like most characters to a long and even course of evolutionary progress, but to sudden spurts of change. —Ronald Fisher, 1930 [9]

Since Fisher's initial conceptual model of the 'runaway' process, Russell Lande and Peter O'Donald have provided detailed mathematical proofs that define the circumstances under which runaway sexual selection can take place. [13] [14] Alongside this, biologists have extended Darwin's formulation; Malte Andersson's widely-accepted [15] 1994 definition is that "sexual selection is the differences in reproduction that arise from variation among individuals in traits that affect success in competition over mates and fertilizations". [11] [15] Despite some practical challenges for biologists, the concept of sexual selection is "straightforward". [15]

Modern theory

Reproductive success

The enormous sexually-selected antlers of the Irish elk might have helped it on its way to extinction. Irish Elk front.jpg
The enormous sexually-selected antlers of the Irish elk might have helped it on its way to extinction.

The reproductive success of an organism is measured by the number of offspring left behind, and by their quality or probable fitness. [17] [18] [19] Sexual preference creates a tendency towards assortative mating or homogamy. The general conditions of sexual discrimination appear to be (1) the acceptance of one mate precludes the effective acceptance of alternative mates, and (2) the rejection of an offer is followed by other offers, either certainly or at such high chance that the risk of non-occurrence is smaller than the chance advantage to be gained by selecting a mate. Bateman's principle states that the sex which invests the most in producing offspring becomes a limiting resource for which the other sex competes, illustrated by the greater nutritional investment of an egg in a zygote, and the limited capacity of females to reproduce; for example, in humans, a woman can only give birth every ten months, whereas a male can become a father numerous times in the same period. [20] More recently, researchers have doubted whether Bateman was correct. [21]

Honest signalling

The handicap principle of Amotz Zahavi, Russell Lande and W. D. Hamilton, holds that the male's survival until and through the age of reproduction with seemingly maladaptive traits is taken by the female as a signal of his overall fitness. Such handicaps might prove he is either free of or resistant to disease, or that he possesses more speed or a greater physical strength that is used to combat the troubles brought on by the exaggerated trait. [22] [23] [24] Zahavi's work spurred a re-examination of the field and several new theories. In 1984, Hamilton and Marlene Zuk introduced the "Bright Male" hypothesis, suggesting that male elaborations might serve as a marker of health, by exaggerating the effects of disease and deficiency. [25]

Male intrasexual competition

Male mountain gorilla, a species with very large males Susa group, mountain gorilla.jpg
Male mountain gorilla, a species with very large males

Male–male competition occurs when two males of the same species compete for the opportunity to mate with a female. Sexually dimorphic traits, size, sex ratio, [27] and the social situation [28] may all play a role in the effects male–male competition has on the reproductive success of a male and the mate choice of a female. Larger males tend to win male–male conflicts. [29] Males take many risks in such conflicts, so the value of the resource must be large enough to justify those risks. [30] [31] Winner and loser effects further influence male behaviour. [32] Male–male competition may also affect a female's ability to select the best mates, and therefore decrease the likelihood of successful reproduction. [33]

Multiple models

More recently, the field has grown to include other areas of study, not all of which fit Darwin's definition of sexual selection. A "bewildering" [34] range of models variously attempt to relate sexual selection not only to the fundamental [34] questions of anisogamy and parental roles, but also to mechanisms such as sex ratios – governed by Fisher's principle, [35] parental care, investing in sexy sons, sexual conflict, and the "most-debated effect", [34] namely mate choice. [34] Elaborated characteristics that might seem costly, like the tail of the Montezuma swordfish ( Xiphophorus montezumae ), do not always have an energetics, performance or even survival cost; this may be because "compensatory traits" have evolved in concert with the sexually selected traits. [36]

Toolkit of natural selection

Protarchaeopteryx was flightless, but had feathers, perhaps used in courtship, that pre-adapted it for flight. Protarchaeopteryx 4713.JPG
Protarchaeopteryx was flightless, but had feathers, perhaps used in courtship, that pre-adapted it for flight.

Sexual selection may explain how characteristics such as feathers had survival value at an early stage in their evolution. The earliest proto-birds such as Protarchaeopteryx had well-developed feathers but could not fly. The feathers may have served as insulation, helping females incubate their eggs, but if proto-bird courtship combined displays of forelimb feathers with energetic jumps, then the transition to flight could have been relatively smooth. [37]

Sexual selection may sometimes generate features that help cause a species' extinction, as has historically been suggested for the giant antlers of the Irish elk (Megaloceros giganteus) that became extinct in Holocene [38] Eurasia [16] (although climate-induced habitat deterioration and anthropogenic pressure are now considered more likely causes). [39] It may, however, also do the opposite, driving species divergence—sometimes through elaborate changes in genitalia [40] —such that new species emerge. [41] [42]

In different taxa

Sexual selection is widely distributed among the eukaryotes, occurring in plants, fungi, and animals. Since Darwin's pioneering observations on humans, it has been studied intensively among the insects, spiders, amphibians, scaled reptiles, birds, and mammals, revealing many distinctive behaviours and physical adaptations. [43]

In mammals

Darwin conjectured that heritable traits such as beards, hairlessness, and steatopygia in different human populations are results of sexual selection in humans. [44] Humans are sexually dimorphic; females select males using factors including voice pitch, facial shape, muscularity, and height. [45] [46]

Among the many instances of sexual selection in mammals is extreme sexual dimorphism, with males as much as six times heavier than females, and male fighting for dominance among elephant seals. Dominant males establish large harems of several dozen females; unsuccessful males may attempt to copulate with a harem male's females if the dominant male is inattentive. This forces the harem male to defend his territory continuously, not feeding for as much as three months. [47] [48]

Also seen in mammals is sex-role reversal, as in the highly social meerkats, where a large female is dominant within a pack, and female–female competition is observed. The dominant female produces most of the offspring; the subordinate females are nonbreeding, providing altruistic care to the young. [49] [50]

In arthropods

Sexual selection occurs in a wide range of spider species, both before and after copulation. [51] Post-copulatory sexual selection involves sperm competition and cryptic female choice. Sperm competition occurs where the sperm of more than one male competes to fertilise the egg of the female. Cryptic female choice involves the expelling of a male's sperm during or after copulations. [52]

Many forms of sexual selection exist among the insects. Parental care is often provided by female insects, as in bees, but male parental care is found in belostomatid water bugs, where the male, after fertilizing the eggs, allows the female to glue her eggs onto his back. He broods them until the nymphs hatch 2–4 weeks later. The eggs are large and reduce the ability of the male to fertilise other females and catch prey, and increases its predation risk. [53]

Among the fireflies (Lampyrid beetles), males fly in darkness and emit a species-specific pattern of light flashes, which are answered by perching receptive females. The colour and temporal variation of the flashes contribute to success in attracting females. [54] [55] [56] Among the beetles, sexual selection is common. In the mealworm beetle, Tenebrio molitor, males release pheromones to attract females to mate. [57] Females choose mates based on whether they are infected, and on their mass. [58]

In molluscs

Postcopulatory intersexual selection occurs in Idiosepius paradoxus , the Japanese pygmy squid. Males place their spermatangia on an external location on the female's body. The female physically removes spermatangia of males she is presumed to favour less. [59] [60]

In amphibians and reptiles

Many amphibians have annual breeding seasons with male–male competition. Males arrive at the water's edge first in large numbers, and produce a wide range of vocalizations to attract mates. Among frogs, the fittest males have the deepest croaks and the best territories; females select their mates at least partly based on the depth of croaking. This has led to sexual dimorphism, with females larger than males in 90% of species, and male fighting to access females. [61] [62] Spikethumb frogs are suggested to engage in male-male competition with their elongated prepollex to maintain their mating site. [63] The prepollex, which serves as a rudimentary digit, contains a projecting spine that may be used during this combat, leaving scars on the head and forelimbs of other males. [64] Some species, like P. bibronii , are polyandrous, with one female mating with multiple males.

Many different tactics are used by snakes to acquire mates. Ritual combat between males for the females they want to mate with includes topping, a behavior exhibited by most viperids in which one male will twist around the vertically elevated fore body of its opponent and forcing it downward. It is common for neck biting to occur while the snakes are entwined. [65] [66]

In birds

Birds have evolved a wide variety of mating behaviours and many types of sexual selection. These include intersexual selection (female choice) and intrasexual competition, where individuals of the more abundant sex compete with each other for the privilege to mate. Many species, notably the birds-of-paradise, are sexually dimorphic; the differences such as in size and coloration are energetically costly attributes that signal competitive breeding. Conflicts between an individual's fitness and signalling adaptations ensure that sexually selected ornaments such as coloration of plumage and courtship behaviour are honest traits. Signals must be costly to ensure that only good-quality individuals can present these exaggerated sexual ornaments and behaviours. Males with the brightest plumage are favoured by females of multiple species of bird. [67] [68] [69]

Many bird species make use of mating calls, the females preferring males with songs that are complex and varied in amplitude, structure, and frequency. Larger males have deeper songs and increased mating success. [70] [71] [72] [73]

In plants and fungi

Flowering plants have many secondary sexual characteristics subject to sexual selection including floral symmetry if pollinators visit flowers assortatively by degree of symmetry, [74] nectar production, floral structure, and inflorescences, as well as sexual dimorphisms. [75] [76] [77]

Fungi appear to make use of sexual selection, although they also often reproduce asexually. In the Basidiomycetes, the sex ratio is biased towards males, implying sexual selection there. Male–male competition to fertilise occurs in fungi including yeasts. Pheromone signaling is used by female gametes and by conidia, implying male choice in these cases. Female–female competition may also occur, indicated by the much faster evolution of female-biased genes in fungi. [43] [78] [79] [80]

Related Research Articles

<span class="mw-page-title-main">Sexual dimorphism</span> Evolved difference in sex-specific characteristics

Sexual dimorphism is the condition where sexes of the same species exhibit different morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecious species, which consist of most animals and some plants. Differences may include secondary sex characteristics, size, weight, color, markings, or behavioral or cognitive traits. Male-male reproductive competition has evolved a diverse array of sexually dimorphic traits. Aggressive utility traits such as "battle" teeth and blunt heads reinforced as battering rams are used as weapons in aggressive interactions between rivals. Passive displays such as ornamental feathering or song-calling have also evolved mainly through sexual selection. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is monomorphism, when both biological sexes are phenotypically indistinguishable from each other.

<span class="mw-page-title-main">Lek mating</span> Type of animal mating behaviour

A lek is an aggregation of male animals gathered to engage in competitive displays and courtship rituals, known as lekking, to entice visiting females which are surveying prospective partners with which to mate. It can also refer to a space used by displaying males to defend their own share of territory for the breeding season. A lekking species is characterised by male displays, strong female mate choice, and the conferring of indirect benefits to males and reduced costs to females. Although most prevalent among birds such as black grouse, lekking is also found in a wide range of vertebrates including some bony fish, amphibians, reptiles, mammals, and arthropods including crustaceans and insects.

<span class="mw-page-title-main">Behavioral ecology</span> Study of the evolutionary basis for animal behavior due to ecological pressures

Behavioral ecology, also spelled behavioural ecology, is the study of the evolutionary basis for animal behavior due to ecological pressures. Behavioral ecology emerged from ethology after Niko Tinbergen outlined four questions to address when studying animal behaviors: What are the proximate causes, ontogeny, survival value, and phylogeny of a behavior?

<span class="mw-page-title-main">Handicap principle</span> Hypothesis in evolutionary biology

The handicap principle is a disputed hypothesis proposed by the Israeli biologist Amotz Zahavi in 1975. It is meant to explain how "signal selection" during mate choice may lead to "honest" or reliable signalling between male and female animals which have an obvious motivation to bluff or deceive each other. The handicap principle suggests that secondary sexual characteristics are costly signals which must be reliable, as they cost the signaller resources that individuals with less of a particular trait could not afford. The handicap principle further proposes that animals of greater biological fitness signal this through handicapping behaviour, or morphology that effectively lowers overall fitness. The central idea is that sexually selected traits function like conspicuous consumption, signalling the ability to afford to squander a resource. Receivers then know that the signal indicates quality, because inferior-quality signallers are unable to produce such wastefully extravagant signals.

<span class="mw-page-title-main">Fisherian runaway</span> Sexual selection mechanism

Fisherian runaway or runaway selection is a sexual selection mechanism proposed by the mathematical biologist Ronald Fisher in the early 20th century, to account for the evolution of ostentatious male ornamentation by persistent, directional female choice. An example is the colourful and elaborate peacock plumage compared to the relatively subdued peahen plumage; the costly ornaments, notably the bird's extremely long tail, appear to be incompatible with natural selection. Fisherian runaway can be postulated to include sexually dimorphic phenotypic traits such as behavior expressed by a particular sex.

<span class="mw-page-title-main">Anisogamy</span> Sexual reproduction involving a large, female gamete and a small, male gamete

Anisogamy is a form of sexual reproduction that involves the union or fusion of two gametes that differ in size and/or form. The smaller gamete is male, a sperm cell, whereas the larger gamete is female, typically an egg cell. Anisogamy is predominant among multicellular organisms. In both plants and animals, gamete size difference is the fundamental difference between females and males.

Monogamous pairing in animals refers to the natural history of mating systems in which species pair bond to raise offspring. This is associated, usually implicitly, with sexual monogamy.

<span class="mw-page-title-main">Sexual conflict</span> Term in evolutionary biology

Sexual conflict or sexual antagonism occurs when the two sexes have conflicting optimal fitness strategies concerning reproduction, particularly over the mode and frequency of mating, potentially leading to an evolutionary arms race between males and females. In one example, males may benefit from multiple matings, while multiple matings may harm or endanger females due to the anatomical differences of that species. Sexual conflict underlies the evolutionary distinction between male and female.

<span class="mw-page-title-main">Mate choice</span> Mechanism for evolution

Mate choice is one of the primary mechanisms under which evolution can occur. It is characterized by a "selective response by animals to particular stimuli" which can be observed as behavior. In other words, before an animal engages with a potential mate, they first evaluate various aspects of that mate which are indicative of quality—such as the resources or phenotypes they have—and evaluate whether or not those particular trait(s) are somehow beneficial to them. The evaluation will then incur a response of some sort.

<span class="mw-page-title-main">Sexy son hypothesis</span> Postulate in biology

The sexy son hypothesis in evolutionary biology and sexual selection, proposed by Patrick J. Weatherhead and Raleigh J. Robertson of Queen's University in Kingston, Ontario in 1979, states that a female's ideal mate choice among potential mates is one whose genes will produce males with the best chance of reproductive success. This implies that other benefits the father can offer the mother or offspring are less relevant than they may appear, including his capacity as a parental caregiver, territory and any nuptial gifts. Fisher's principle means that the sex ratio is always near 1:1 between males and females, yet what matters most are her "sexy sons'" future breeding successes, more likely if they have a promiscuous father, in creating large numbers of offspring carrying copies of her genes. This sexual selection hypothesis has been researched in species such as the European pied flycatcher.

<span class="mw-page-title-main">Courtship display</span> Communication to start a relationship with someone or to get sexual contact

A courtship display is a set of display behaviors in which an animal, usually a male, attempts to attract a mate; the mate exercises choice, so sexual selection acts on the display. These behaviors often include ritualized movement ("dances"), vocalizations, mechanical sound production, or displays of beauty, strength, or agonistic ability.

<span class="mw-page-title-main">Sexual selection in humans</span> Evolutionary effects of sexual selection on humans

Sexual selection in humans concerns the concept of sexual selection, introduced by Charles Darwin as an element of his theory of natural selection, as it affects humans. Sexual selection is a biological way one sex chooses a mate for the best reproductive success. Most compete with others of the same sex for the best mate to contribute their genome for future generations. This has shaped human evolution for many years, but reasons why humans choose their mates are not fully understood. Sexual selection is quite different in non-human animals than humans as they feel more of the evolutionary pressures to reproduce and can easily reject a mate. The role of sexual selection in human evolution has not been firmly established although neoteny has been cited as being caused by human sexual selection. It has been suggested that sexual selection played a part in the evolution of the anatomically modern human brain, i.e. the structures responsible for social intelligence underwent positive selection as a sexual ornamentation to be used in courtship rather than for survival itself, and that it has developed in ways outlined by Ronald Fisher in the Fisherian runaway model. Fisher also stated that the development of sexual selection was "more favourable" in humans.

Sexual antagonistic co-evolution is the relationship between males and females where sexual morphology changes over time to counteract the opposite's sex traits to achieve the maximum reproductive success. This has been compared to an arms race between sexes. In many cases, male mating behavior is detrimental to the female's fitness. For example, when insects reproduce by means of traumatic insemination, it is very disadvantageous to the female's health. During mating, males will try to inseminate as many females as possible, however, the more times a female's abdomen is punctured, the less likely she is to survive. Females that possess traits to avoid multiple matings will be more likely to survive, resulting in a change in morphology. In males, genitalia is relatively simple and more likely to vary among generations compared to female genitalia. This results in a new trait that females have to avoid in order to survive.

A biological ornament is a characteristic of an animal that appears to serve a decorative function rather than a utilitarian function. Many are secondary sexual characteristics, and others appear on young birds during the period when they are dependent on being fed by their parents. Ornaments are used in displays to attract mates, which may lead to the evolutionary process known as sexual selection. An animal may shake, lengthen, or spread out its ornament in order to get the attention of the opposite sex, which will in turn choose the most attractive one with which to mate. Ornaments are most often observed in males, and choosing an extravagantly ornamented male benefits females as the genes that produce the ornament will be passed on to her offspring, increasing their own reproductive fitness. As Ronald Fisher noted, the male offspring will inherit the ornament while the female offspring will inherit the preference for said ornament, which can lead to a positive feedback loop known as a Fisherian runaway. These structures serve as cues to animal sexual behaviour, that is, they are sensory signals that affect mating responses. Therefore, ornamental traits are often selected by mate choice.

Interlocus sexual conflict is a type of sexual conflict that occurs through the interaction of a set of antagonistic alleles at two or more different loci, or the location of a gene on a chromosome, in males and females, resulting in the deviation of either or both sexes from the fitness optima for the traits. A co-evolutionary arms race is established between the sexes in which either sex evolves a set of antagonistic adaptations that is detrimental to the fitness of the other sex. The potential for reproductive success in one organism is strengthened while the fitness of the opposite sex is weakened. Interlocus sexual conflict can arise due to aspects of male–female interactions such as mating frequency, fertilization, relative parental effort, female remating behavior, and female reproductive rate.

Intralocus sexual conflict is a type of sexual conflict that occurs when a genetic locus harbours alleles which have opposing effects on the fitness of each sex, such that one allele improves the fitness of males, while the alternative allele improves the fitness of females. Such "sexually antagonistic" polymorphisms are ultimately generated by two forces: (i) the divergent reproductive roles of each sex, such as conflicts over optimal mating strategy, and (ii) the shared genome of both sexes, which generates positive between-sex genetic correlations for most traits. In the long term, intralocus sexual conflict is resolved when genetic mechanisms evolve that decouple the between-sex genetic correlations between traits. This can be achieved, for example, via the evolution of sex-biased or sex-limited genes.

<span class="mw-page-title-main">Sexual swelling</span> Swelling of genital and perineal skin in some mammals as a sign of fertility

Sexual swelling, sexual skin, or anogenital tumescence refers to localized engorgement of the anus and vulva region of some female primates that vary in size over the course of the menstrual cycle. Thought to be an honest signal of fertility, male primates are attracted to these swellings; preferring, and competing for, females with the largest swellings.

<span class="mw-page-title-main">Sexual selection in birds</span>

Sexual selection in birds concerns how birds have evolved a variety of mating behaviors, with the peacock tail being perhaps the most famous example of sexual selection and the Fisherian runaway. Commonly occurring sexual dimorphisms such as size and color differences are energetically costly attributes that signal competitive breeding situations. Many types of avian sexual selection have been identified; intersexual selection, also known as female choice; and intrasexual competition, where individuals of the more abundant sex compete with each other for the privilege to mate. Sexually selected traits often evolve to become more pronounced in competitive breeding situations until the trait begins to limit the individual's fitness. Conflicts between an individual fitness and signaling adaptations ensure that sexually selected ornaments such as plumage coloration and courtship behavior are "honest" traits. Signals must be costly to ensure that only good-quality individuals can present these exaggerated sexual ornaments and behaviors.

<span class="mw-page-title-main">Sexual selection in mammals</span> Mode of natural selection

Sexual selection in mammals is a process the study of which started with Charles Darwin's observations concerning sexual selection, including sexual selection in humans, and in other mammals, consisting of male–male competition and mate choice that mold the development of future phenotypes in a population for a given species.

<span class="mw-page-title-main">Sexual selection in amphibians</span> Choice of and competition for mates

Sexual selection in amphibians involves sexual selection processes in amphibians, including frogs, salamanders and newts. Prolonged breeders, the majority of frog species, have breeding seasons at regular intervals where male-male competition occurs with males arriving at the waters edge first in large number and producing a wide range of vocalizations, with variations in depth of calls the speed of calls and other complex behaviours to attract mates. The fittest males will have the deepest croaks and the best territories, with females making their mate choices at least partly based on the males depth of croaking. This has led to sexual dimorphism, with females being larger than males in 90% of species, males in 10% and males fighting for groups of females.

References

  1. ↑ Darwin, Charles (1858). "On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection" (PDF). Journal of the Proceedings of the Linnean Society of London. Zoology. 3 (9): 46–50. doi: 10.1111/j.1096-3642.1858.tb02500.x . Archived (PDF) from the original on 22 October 2012.
  2. ↑ Mendelson, Tamra C.; Safran, Rebecca J. (2021). "Speciation by sexual selection: 20 years of progress". Trends in Ecology & Evolution . 36 (12): 1153–1163. doi:10.1016/j.tree.2021.09.004.
  3. ↑ Darwin, Charles (1859). On the Origin of Species (1st edition). Chapter 4, p. 88. "And this leads me to say a few words on what I call Sexual Selection. This depends ..." "Archived copy". Archived from the original on 2011-11-05. Retrieved 2011-05-22.{{cite web}}: CS1 maint: archived copy as title (link)
  4. ↑ Darwin, Charles (1859). On the Origin of Species (1st edition). Chapter 4, p. 89. "Archived copy". Archived from the original on 2011-11-05. Retrieved 2011-05-22.{{cite web}}: CS1 maint: archived copy as title (link)
  5. ↑ Wallace, Alfred Russel (1892). "Note on Sexual Selection (S459: 1892)". Charles Smith. Archived from the original on 17 February 2017. Retrieved 13 January 2017.
  6. 1 2 Population benefits of sexual selection explain the existence of males phys.org May 18, 2015 Report on a study by the University of East Anglia Archived August 21, 2015, at the Wayback Machine
  7. ↑ Miller, G. F. (2000). The Mating Mind: How sexual choice shaped the evolution of human nature. London: Heinemann. p. 24. ISBN   978-0-434-00741-7.
  8. ↑ Hosken, David J.; House, Clarissa M. (January 2011). "Sexual Selection". Current Biology. 21 (2): R62–R65. Bibcode:2011CBio...21..R62H. doi: 10.1016/j.cub.2010.11.053 . PMID   21256434. S2CID   18470445.
  9. 1 2 3 Fisher, R. A. (1930) The Genetical Theory of Natural Selection . Oxford University Press, ISBN   0-19-850440-3, Chapter 6.
  10. 1 2 3 4 Dawkins, Richard (1996). The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design. Norton. pp. Chapter 8, Explosions and Spirals. ISBN   978-0-393-31570-7.
  11. 1 2 Andersson, M. (1994). Sexual Selection. Princeton University Press. pp. 115–117. ISBN   0-691-00057-3.
  12. ↑ Ronald Fisher in a letter to Charles Galton Darwin, 22 November 1932, cited in Fisher, R. A., Bennett, J. H. 1999. The genetical theory of natural selection: A complete variorum edition, Oxford University Press, Oxford, p. 308
  13. ↑ Lande, Russell (1981). "Models of speciation by sexual selection on polygenic traits". PNAS. 78 (6): 3721–3725. Bibcode:1981PNAS...78.3721L. doi: 10.1073/pnas.78.6.3721 . PMC   319643 . PMID   16593036.
  14. ↑ O'Donald, Peter (1980). Genetic Models of Sexual Selection. Cambridge University Press. ISBN   9780521225335.
  15. 1 2 3 Kokko, H.; Jennions, M. D. (18 July 2014). "The Relationship between Sexual Selection and Sexual Conflict". Cold Spring Harbor Perspectives in Biology. 6 (9). Cold Spring Harbor Laboratory: a017517. doi:10.1101/cshperspect.a017517. ISSN   1943-0264. PMC   4142970 . PMID   25038050.
  16. 1 2 Gould, Stephen Jay (1974). "Origin and Function of 'Bizarre' Structures – Antler Size and Skull Size in 'Irish Elk', Megaloceros giganteus". Evolution. 28 (2): 191–220. doi:10.2307/2407322. JSTOR   2407322. PMID   28563271.
  17. ↑ Orr, H. A. (August 2009). "Fitness and its role in evolutionary genetics". Nature Reviews Genetics. 10 (8): 531–9. doi:10.1038/nrg2603. PMC   2753274 . PMID   19546856.
  18. ↑ Starr, Cecie (2013). Biology: The Unity & Diversity of Life. Cengage Learning. p. 281.
  19. ↑ Vogt, Yngve (January 29, 2014). "Large testicles are linked to infidelity". Phys.org . Archived from the original on January 31, 2014. Retrieved January 31, 2014.
  20. ↑ Bateman, Angus J. (1948). "Intra-sexual selection in Drosophila". Heredity. 2 (Pt. 3): 349–368. doi: 10.1038/hdy.1948.21 . PMID   18103134.
  21. ↑ Newcomer, Scott D.; Zeh, Jeanne A.; Zeh, David W. (31 August 1999). "Genetic benefits enhance the reproductive success of polyandrous females". Proceedings of the National Academy of Sciences. 96 (18): 10236–10241. Bibcode:1999PNAS...9610236N. doi: 10.1073/pnas.96.18.10236 . PMC   17872 . PMID   10468592.
  22. ↑ Zahavi, Amotz (1975). "Mate selection—A selection for a handicap". Journal of Theoretical Biology. 53 (1): 205–214. Bibcode:1975JThBi..53..205Z. doi:10.1016/0022-5193(75)90111-3. PMID   1195756.
  23. ↑ Zahavi, Amotz (1977). "The cost of honesty". Journal of Theoretical Biology. 67 (3): 603–605. Bibcode:1977JThBi..67..603Z. doi:10.1016/0022-5193(77)90061-3. ISSN   0022-5193. PMID   904334.
  24. ↑ Zahavi, Amotz; Zahavi, Avishag (1997). The handicap principle: a missing piece of Darwin's puzzle (PDF). New York: Oxford University Press. ISBN   978-0-19-510035-8. OCLC   35360821.
  25. ↑ Hamilton, W. D.; Zuk, M. (1982). "Heritable true fitness and bright birds: a role for parasites?". Science. 218 (4570): 384–387. Bibcode:1982Sci...218..384H. doi:10.1126/science.7123238. PMID   7123238.
  26. ↑ Williamson, E. A.; Butynski, T. M. (2013). "Gorilla beringei eastern gorilla". In Butynski, T. M.; Kingdon, J.; Kalina, J. (eds.). Mammals of Africa. Vol. 2. Primates. London, New Delhi, New York, Sydney: Bloomsbury. pp. 45–53. ISBN   9781408189962.
  27. ↑ Weir, Laura K. (2012-11-22). "Male–male competition and alternative male mating tactics influence female behavior and fertility in Japanese medaka (Oryzias latipes)". Behavioral Ecology and Sociobiology. 67 (2): 193–203. doi:10.1007/s00265-012-1438-9. S2CID   15410498.
  28. ↑ Proctor, D. S.; Moore, A. J.; Miller, C. W. (2012-03-09). "The form of sexual selection arising from male–male competition depends on the presence of females in the social environment". Journal of Evolutionary Biology. 25 (5): 803–812. doi:10.1111/j.1420-9101.2012.02485.x. PMID   22404372. S2CID   594384.
  29. ↑ Otronen, Merja (1984-08-01). "Male contests for territories and females in the fly Dryomyza Anilis". Animal Behaviour. 32 (3): 891–898. doi:10.1016/S0003-3472(84)80167-0. S2CID   53188298.
  30. ↑ Nelson-Flower, Martha J.; Ridley, Amanda R. (2015-09-24). "Male–male competition is not costly to dominant males in a cooperatively breeding bird". Behavioral Ecology and Sociobiology. 69 (12): 1997–2004. doi:10.1007/s00265-015-2011-0. ISSN   0340-5443. S2CID   15032582.
  31. ↑ Luo, Zhenhua; Li, Chenliang; Wang, Hui; et al. (2016-02-23). "Male–male competition drives sexual selection and group spawning in the Omei treefrog, Rhacophorus omeimontis". Behavioral Ecology and Sociobiology. 70 (4): 593–605. doi:10.1007/s00265-016-2078-2. ISSN   0340-5443. S2CID   13912038.
  32. ↑ Zeng, Yang; Zhou, Feng-Hao; Zhu, Dao-Hong (2018-06-26). "Fight outcome briefly affects the reproductive fitness of male crickets". Scientific Reports. 8 (1): 9695. Bibcode:2018NatSR...8.9695Z. doi:10.1038/s41598-018-27866-4. PMC   6018733 . PMID   29946077.
  33. ↑ Cayuela, Hugo; Lengagne, Thierry; Kaufmann, Bernard; Joly, Pierre; Léna, Jean-Paul (2016-06-24). "Larval competition risk shapes male–male competition and mating behavior in an anuran". Behavioral Ecology. 27 (6): arw100. doi: 10.1093/beheco/arw100 .
  34. 1 2 3 4 Kokko, Hanna; Jennions, Michael D.; Brooks, Robert (2006). "Unifying and Testing Models of Sexual Selection" (PDF). Annual Review of Ecology, Evolution, and Systematics. 37 (1): 43–66. doi:10.1146/annurev.ecolsys.37.091305.110259. hdl: 1885/22652 .
  35. ↑ Hamilton, W. D. (1967). "Extraordinary sex ratios". Science. 156 (3774): 477–488. Bibcode:1967Sci...156..477H. doi:10.1126/science.156.3774.477. PMID   6021675.
  36. ↑ Oufiero, Christopher E. (May 2015). "Sexual Selection, Costs, and Compensation". University of California Riverside. Archived from the original on 6 June 2014.
  37. ↑ Clarke, J. (9 May 2013). "Feathers Before Flight". Science. 340 (6133): 690–692. Bibcode:2013Sci...340..690C. doi:10.1126/science.1235463. PMID   23661746. S2CID   31802107.
  38. ↑ van der Plicht, J.; Molodin, V. I.; Kuzmin, Y. V.; Vasiliev, S. K.; Postnov, A. V.; Slavinsky, V. S. (15 April 2015). "New Holocene refugia of giant deer (Megaloceros giganteus Blum.) in Siberia: updated extinction patterns". Quaternary Science Reviews. 114: 182–188. Bibcode:2015QSRv..114..182V. doi:10.1016/j.quascirev.2015.02.013. ISSN   0277-3791.
  39. ↑ Lister, Adrian M.; Stuart, Anthony J. (2019-01-01). "The extinction of the giant deer Megaloceros giganteus (Blumenbach): New radiocarbon evidence". Quaternary International. SI: Quaternary International 500. 500: 185–203. Bibcode:2019QuInt.500..185L. doi:10.1016/j.quaint.2019.03.025. ISSN   1040-6182.
  40. ↑ Eberhard, William G. (24 March 2009). "Evolution of genitalia: theories, evidence, and new directions" (PDF). Genetica. 138 (1): 5–18. doi:10.1007/s10709-009-9358-y. PMID   19308664. S2CID   1409845.
  41. ↑ Hosken, David J.; Stockley, Paula. "Sexual selection and genital evolution Archived 12 October 2017 at the Wayback Machine ." Trends in Ecology & Evolution 19.2 (2004): 87–93.
  42. ↑ Arnqvist, Göran. "Comparative evidence for the evolution of genitalia by sexual selection Archived 27 January 2012 at the Wayback Machine ." Nature 393.6687 (1998): 784.
  43. 1 2 Nieuwenhuis, B. P. S.; Aanen, D. K. (2012). "Sexual selection in fungi". Journal of Evolutionary Biology. 25 (12): 2397–2411. doi: 10.1111/jeb.12017 . PMID   23163326. S2CID   5657743.
  44. ↑ Darwin, Charles (1882). The Descent of Man and Selection in Relation to Sex. London: John Murray. p. 578.
  45. ↑ Buss, David (2019). "Women's Long-Term Mating Strategies". Evolutionary Psychology: The New Science of the Mind (Sixth ed.). Routledge. ISBN   9780429590061.
  46. ↑ Feinberg, D. R.; Jones, B. C.; Law Smith, M. J.; et al. (1 February 2006). "Menstrual cycle, trait estrogen level, and masculinity preferences in the human voice". Hormones and Behavior. 49 (2): 215–222. doi:10.1016/j.yhbeh.2005.07.004. PMID   16055126. S2CID   14884832.
  47. ↑ Perrin, William F.; Würsig, Bernd; Thewissen, J. G. M., eds. (2008). "Earless Seals". Encyclopedia of Marine Mammals (2nd ed.). Burlington, Massachusetts: Academic Press. p. 346. ISBN   978-0-12-373553-9.
  48. ↑ McCann, T. S. (1981). "Aggression and sexual activity of male Southern elephant seals, Mirounga leonina". Journal of Zoology. 195 (3): 295–310. doi:10.1111/j.1469-7998.1981.tb03467.x.
  49. ↑ Clutton-Brock, T. H.; Hodge, S. J.; Spong, G. (2006). "Intrasexual competition and sexual selection in cooperative mammals". Nature. 444 (7122): 1065–8. Bibcode:2006Natur.444.1065C. doi:10.1038/nature05386. PMID   17183322. S2CID   4397323.
  50. ↑ Clutton-Brock, T. H.; Russell, A. F.; Sharpe, L. L. (2004). "Behavioural tactics of breeders in cooperative meerkats". Animal Behaviour. 68 (5): 1029–1040. doi:10.1016/j.anbehav.2003.10.024. S2CID   53175143.
  51. ↑ Eberhard, William G. (16 June 2009). "Postcopulatory sexual selection: Darwin's omission and its consequences". Proceedings of the National Academy of Sciences. 106 (supplement 1): 10025–10032. doi: 10.1073/pnas.0901217106 . PMC   2702800 . PMID   19528642.
  52. ↑ Peretti, A. V.; Eberhard, W. G. (2010). "Cryptic female choice via sperm dumping favours male copulatory courtship in a spider". Journal of Evolutionary Biology. 23 (2): 271–281. doi: 10.1111/j.1420-9101.2009.01900.x . PMID   20487130. S2CID   9110472.
  53. ↑ Gilbert, James D. J.; Manica, Andrea (30 April 2015). "The evolution of parental care in insects: A test of current hypotheses". Evolution. 69 (5): 1255–1270. doi:10.1111/evo.12656. PMC   4529740 . PMID   25825047. S2CID   17791711.
  54. ↑ Lewis, Sara M.; Cratsley, Christopher K. (January 2008). "Flash Signal Evolution, Mate Choice, and Predation in Fireflies". Annual Review of Entomology . 53 (1): 293–321. doi:10.1146/annurev.ento.53.103106.093346. PMID   17877452. S2CID   16360536.
  55. ↑ Branham, Marc A.; Wenzel, John W. (December 2001). "The Evolution of Bioluminescence in Cantharoids (Coleoptera: Elateroidea)". The Florida Entomologist . 84 (4): 565. doi: 10.2307/3496389 . JSTOR   3496389.
  56. ↑ Martin, Gavin J.; Branham, Marc A.; Whiting, Michael F.; Bybee, Seth M. (February 2017). "Total evidence phylogeny and the evolution of adult bioluminescence in fireflies (Coleoptera: Lampyridae)". Molecular Phylogenetics and Evolution . 107: 564–575. Bibcode:2017MolPE.107..564M. doi: 10.1016/j.ympev.2016.12.017 . PMID   27998815.
  57. ↑ Pölkki, Mari; Krams, Indrikis; Kangassalo, Katariina; Rantala, Markus J. (2012-06-23). "Inbreeding affects sexual signalling in males but not females of Tenebrio molitor". Biology Letters. 8 (3): 423–425. doi:10.1098/rsbl.2011.1135. ISSN   1744-9561. PMC   3367757 . PMID   22237501.
  58. ↑ Worden, Bradley D.; Parker, Patricia G. (2005-11-05). "Females prefer noninfected males as mates in the grain beetle Tenebrio molitor: evidence in pre- and postcopulatory behaviours". Animal Behaviour. 70 (5): 1047–1053. doi:10.1016/j.anbehav.2005.01.023.
  59. ↑ Sato, Noriyosi; Yoshida, Masa-aki; Kasugai, Takashi (2016-11-17). "Impact of cryptic female choice on insemination success: Larger sized and longer copulating male squid ejaculate more, but females influence insemination success by removing spermatangia". Evolution. 71 (1): 111–120. doi:10.1111/evo.13108. ISSN   0014-3820. PMID   27805265. S2CID   8866473.
  60. ↑ Sato, Noriyosi; Kasugai, Takashi; Munehara, Hiroyuki (2013-03-01). "Sperm transfer or spermatangia removal: postcopulatory behaviour of picking up spermatangium by female Japanese pygmy squid". Marine Biology. 160 (3): 553–561. Bibcode:2013MarBi.160..553S. doi:10.1007/s00227-012-2112-5. hdl: 10069/31698 . ISSN   1432-1793. S2CID   253740276.
  61. ↑ Phelps, S.; Rand, A.; Ryan, M. (2006). "A cognitive framework for mate choice and species recognition". The American Naturalist. 167 (1): 28–42. doi:10.1086/498538. PMID   16475097. S2CID   15851718.
  62. ↑ Wells, Kentwood D.; Schwartz, Joshua J. (2006). "The Behavioral Ecology of Anuran Communication". Hearing and Sound Communication in Amphibians (PDF). Springer Handbook of Auditory Research. Vol. 28. New York: Springer. pp. 44–86. doi:10.1007/978-0-387-47796-1_3. ISBN   978-0-387-32521-7. S2CID   160384362.
  63. ↑ Gonzalez-Mollinedo, S.; Marmol-Kattan, A. (2020). "The underground sex life of the Guatemalan Spike-thumb Frog (Plectrohyla guatemalensis)". Neotropical Biology and Conservation. 15 (4): 551–559. doi: 10.3897/neotropical.15.e57142 .
  64. ↑ Duellman, W.E.; Campbell, J.A. (1992). "Hylid frogs of the genus Plectrohyla: systematics and phylogenetic relationships" (PDF). Museum of Zoology, University of Michigan (181).
  65. ↑ Shine, Richard; Langkilde, Tracy; Mason, Robert T. (2004). "Courtship tactics in garter snakes: How do a male's morphology and behaviour influence his mating success?". Animal Behaviour. 67 (3): 477–483. doi:10.1016/j.anbehav.2003.05.007. S2CID   4830666.
  66. ↑ Blouin-Demers, Gabriel; Gibbs, H. Lisle; Weatherhead, Patrick J. (2005). "Genetic evidence for sexual selection in black ratsnakes, Elaphe obsoleta". Animal Behaviour. 69 (1): 225–34. doi:10.1016/j.anbehav.2004.03.012. S2CID   3907523.
  67. ↑ Saino, Nicola; Romano, Maria; Rubolini, Diego; et al. (2013). "Sexual Dimorphism in Melanin Pigmentation, Feather Coloration and Its Heritability in the Barn Swallow (Hirundo rustica)". PLOS ONE. 8 (2): e58024. Bibcode:2013PLoSO...858024S. doi: 10.1371/journal.pone.0058024 . PMC   3585210 . PMID   23469134.
  68. ↑ Edwards, D.B. (2012). "Immune investment is explained by sexual selection and pace-of-life, but not longevity in parrots (Psittaciformes)". PLOS ONE. 7 (12): e53066. Bibcode:2012PLoSO...753066E. doi: 10.1371/journal.pone.0053066 . PMC   3531452 . PMID   23300862.
  69. ↑ Doutrelant, C.; Grégoire, A.; Midamegbe, A.; Lambrechts, M.; Perret, P. (January 2012). "Female plumage coloration is sensitive to the cost of reproduction. An experiment in blue tits". Journal of Animal Ecology . 81 (1): 87–96. Bibcode:2012JAnEc..81...87D. doi: 10.1111/j.1365-2656.2011.01889.x . PMID   21819397.
  70. ↑ Hall, L.; Kingma, S. A.; Peters, A. (2013). "Male songbird indicates body size with low-pitched advertising songs". PLOS ONE. 8 (2): e56717. Bibcode:2013PLoSO...856717H. doi: 10.1371/journal.pone.0056717 . PMC   3577745 . PMID   23437221.
  71. ↑ Pfaff, J. A.; Zanette, L.; MacDougall-Shackleton, S. A.; MacDougall-Shackleton, E. A. (22 August 2007). "Song repertoire size varies with HVC volume and is indicative of male quality in song sparrows (Melospiza melodia)". Proceedings of the Royal Society B . 274 (1621): 2035–40. doi:10.1098/rspb.2007.0170. PMC   2275172 . PMID   17567560.
  72. ↑ Nemeth, E.; Kempenaers, B.; Matessi, G.; Brumm, H. (2012). "Rock sparrow song reflects male age and reproductive success". PLOS ONE. 7 (8): e43259. Bibcode:2012PLoSO...743259N. doi: 10.1371/journal.pone.0043259 . PMC   3426517 . PMID   22927955.
  73. ↑ Mikula, P.; Valcu, M.; Brumm, H.; Bulla, M.; Forstmeier, W.; Petrusková, T.; Kempenaers, B.; Albrecht, T (2021). "A global analysis of song frequency in passerines provides no support for the acoustic adaptation hypothesis but suggests a role for sexual selection". Ecology Letters. 24 (3): 477–486. Bibcode:2021EcolL..24..477M. doi: 10.1111/ele.13662 . PMID   33314573. S2CID   229176172.
  74. ↑ Møller, Anders Pape; Eriksson, Mats (1995). "Pollinator Preference for Symmetrical Flowers and Sexual Selection in Plants". Oikos. 73 (1): 15–22. Bibcode:1995Oikos..73...15M. doi:10.2307/3545720. JSTOR   3545720.
  75. ↑ Ashman, Tia-Lynn; Delph, Lynda F. (1 August 2006). "Trait selection in flowering plants: how does sexual selection contribute?". Integrative and Comparative Biology. 46 (4): 465–472. doi: 10.1093/icb/icj038 . PMID   21672758.
  76. ↑ Moore, Jamie C.; Pannell, John R. (2011). "Sexual selection in plants". Current Biology. 21 (5): R176–R182. Bibcode:2011CBio...21.R176M. doi: 10.1016/j.cub.2010.12.035 . PMID   21377091. S2CID   18044399.
  77. ↑ Wilson, Mary F. (June 1979). "Sexual Selection In Plants". The American Naturalist. 113 (6): 777–790. doi:10.1086/283437. S2CID   84970789.
  78. ↑ Leonard, Janet L. (1 August 2006). "Sexual selection: lessons from hermaphrodite mating systems". Integrative and Comparative Biology. 46 (4): 349–367. doi: 10.1093/icb/icj041 . PMID   21672747.
  79. ↑ Beekman, Madeleine; Nieuwenhuis, Bart; Ortiz-Barrientos, Daniel; Evans, Jonathan P. (19 October 2016). "Sexual selection in hermaphrodites, sperm and broadcast spawners, plants and fungi". Philosophical Transactions of the Royal Society B: Biological Sciences. 371 (1706). The Royal Society: 20150541. doi:10.1098/rstb.2015.0541. ISSN   0962-8436. PMC   5031625 . PMID   27619704.
  80. ↑ Whittle, Carrie A.; Johannesson, Hanna (20 August 2013). "Evolutionary Dynamics of Sex-Biased Genes in a Hermaphrodite Fungus". Molecular Biology and Evolution. 30 (11). Oxford University Press: 2435–2446. doi: 10.1093/molbev/mst143 . PMID   23966547.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.