Monogamy Mating Strategy may be defined as the strategy where one breeding female and one breeding male are closely associated with each other for several breeding seasons. In mammals, monogamy—a relationship including partners of different sexes—occurs only seldom (3–5% of the 4000 mammalian species). The link may last for a single breeding cycle or the rest of the animal's life. Monogamy does not exclude extra-pair mating, often known as "genetic promiscuity." In actuality, this is rather typical.
Monogamy is a mating style that is inherently unstable. The ability to access a partner's reproductive potential is (relatively) specific. However, the main drawback is that access to other mates is severely limited, especially when males exhibit significant mate-guarding behaviour. The most significant selection pressure leading to the evolution of monogamy is mate-guarding, particularly the guarding by males of females with a good territory or of females that accept the territory of a male.
As is the case in most birds (where 90% of bird species are monogamous and most display biparental care of young), a monogamous connection greatly supports the evolution of male engagement in the upbringing of offspring.
Humans are not strictly monogamous, like the majority of mammals. Nonetheless, a propensity for social monogamy has developed and is strongly reinforced by cultural factors, particularly religion. As a result, monogamy is a standard mating system in some societies, yet, most civilizations (approximately 85%) practise polygamy. The best course of human evolution is monogamy when necessary and polygamy when available.
Both kinds of monogamy are uncommon in mammals, occurring in just around 3% of all species. This might be attributed to substantial sex disparities in mammals' necessary parental investments. Indeed, less than 10% of animals exhibit any evidence of significant paternal involvement. Monogamy is observed in some prosimians (e.g., lemurs), New World monkeys (e.g., marmosets and tamarins), and smaller apes. (e.g., gibbons).
Monogamy is uncommon or unknown among Old World monkeys (such as macaques and baboons) and giant apes (such as chimps, gorillas, and humans). All monogamous primates are arboreal, whereas humans are a terrestrial species.
One response to this query is that humans may possess promiscuous genes despite having a genetic distance from chimpanzees and bonobos. The promiscuity of bonobos and chimpanzees is the most excellent model for mating among the early ancestors of humans because they are most closely related to humans, along with chimpanzees and bonobos. This is another response to the topic. Both responses imply that rather than being monogamous, early humans may have been promiscuous.
Unfortunately, these responses assume that bonobos' and chimpanzees' mating systems have not evolved due to millions of years of evolution. The fossil data strongly contests this presumption. The common ancestor of humans, bonobos, and chimpanzees may not have looked like a present bonobo or chimpanzee, according to Sahelanthropus fossils.
Male lifelong reproductive success typically rises with each extra mate; polygyny favours men greatly. Nevertheless, numerous recent studies have discovered that polyandry can boost women's fitness. This is probably one of the causes of the prevalence of polygamy and the frequent discovery of reproductive polygamy in socially monogamous animals by DNA analysis.
Nonetheless, although monogamy is the rarity and polygamy the rule, many different taxa practise reproductive monogamy. Genetic evidence for reciprocal monogamy, monogyny, or monandry has been found in various species, including birds, seahorses, guinea pigs, sharks, catfish, and shrimp and crabs.
It is fascinating to see why certain animals create lifetime pair connections while others only mate with one partner during a single breeding event. What deciding elements favour single partners over many partners and outweigh their advantages? Expenses of having several partners (and hence advantages of monogamy, monogyny, or monandry) are related to sexual conflict, STDs, and immunological function.
Moreover, males who seek to develop pair bonds with numerous females frequently struggle to adequately care for or defend the broods. So, if polygynous men give birth to fewer offspring than monogynous males, monogyny can be preserved by sexual and natural selection.
The conflict between the sexes arises when one sex gains more from a devoted partner than the other sex does. Male-enforced monandry is common in many species and can take several forms, including severe mate-guarding, frequent copulations, mating plugs, and the transfer of substances (such as sex peptides) that prevent re-mating. Hence, these male adaptations offer significant explanations for why females only mate once, even though doing so would benefit them.
Females can also compel male monogamy. Whereas female-enforced monandry originates primarily to secure or avoid sharing resources, male-enforced monogyny is mostly about securing paternity. When mating with the same male, house sparrow females can be pretty hostile, even killing the young of their rivals. Males care for the nestlings by feeding them.
Mutual mate-guarding can lead to mutual monogamy, which is anticipated to happen when the quality of both sexes is sufficiently different. Both sexes should anticipate intrasexual aggression when monogamy results from mutual mate-guarding. Contrarily, reproduction with one partner (rather than many) can benefit both sexes when monogamy is upheld without being imposed.
Following are the major factors that influence monogamy −
Mate Availability − Monogamy may also develop if there are few available partners due to habitat restrictions, low population density, low mobility, territoriality, or non-overlapping home ranges; for example, it is preferable to stay with one partner rather than go on and look for another.
Habitat Limitation − Habitat that is good for feeding and reproducing is frequently uneven and scarce. Resource scarcity has been proposed as a mechanism for developing mutual monogamy in experts, such as many coral reef fishes.
Cultural Evolution − It is evident that culture has enhanced the prevalence of social monogamy. In many contemporary cultures, marriage is only permitted through social monogamy. In many instances, the adoption of such legislation is a reflection of the growth of Christianity. In recent years, international organisations like the African Union and the United Nations have started to advocate for social monogamy to provide women and men equal rights in marriage.
We still know very little about mating systems in general and monogamy in particular, despite decades of work utilising DNA techniques to determine the paternity of children. More experimental and comparative research is required. Many significant problems remain unresolved for evolutionary behavioural ecologists. Future research on monogamy and alternative mating patterns, in particular, has much potential in the domain of genetic compatibility.