Female mate choice

Term
Female Mate Choice

Definition
The concept of female mate choice describes the factors that contribute to a female's desicion in sexual selection. Traditionally, as popularized by Darwin, female mate choice was thought to (mostly) be determined by male male competition and aesthetics. Which ever male was more dominant in competition and looked healthier was the male she would choose to mate with. The idea was that males would fight against males to gain access to females. It is now widely accepted that female mate choice (often) involves many, many more factors than first previously conceived.

Example(s) of use in context
Female choice in natural selection is often seen as a female choosing a male to mate with after males have competed with each other to impress her. An example of this, given by Randy Nelson, is the process of sexual selection in deer. A female deer will choose a male with the biggest feeding area. The males gains control of a big feeding area by fighting with other males in order to establish a social hierarchy. The males that are better at competing will end up with the bigger feeding area. Males with large antlers and bigger bodies tend to win more fights than those who are not as big. The males with the bigger size and bigger feeding areas have more opportunities to mate because females prefer those with larger feeding areas. Thu, as a result, she ends up mating with males who are better at competition, males who have bigger antlers and bodies and males who are more aggressive, which are all traits that help him gain a bigger feeding area. These traits will be passed on to their offspring. Female choice is often much more complicated than the example of deer. As Sarah Hrdy wrote, in book Mother Nature in the chapter, A New View of Mothers, about infanticide in Langur colonies. About 33% of all infants in langur colonies she studied were killed by males. Males of neighboring troops would sometimes come and invade nearby troops. The invader males would then kill unweaned infants in the colony they just took over in order to make the females begin to ovulate again. The female Langur's would then be  sexually receptive to these new invader males. To avoid reproduction with the new males would put her at a disadvantage compared with the other females who mated with the baby-killing invaders.

One way females langurs attempt to assure her baby will not be killed is by traveling to those neighboring troops and mating with the males from the neighboring troop. She will do this sometimes even when she is not ovulating or already pregnant,. She will do this because she knows that if the neighbouring troop ever takes over her troop, a male langur will almost never kill an infant that a female he has mated with produced. She will mate with him as a way of safeguarding her infant.

This examples shows how female choice is often more complicated than usually described by the sexual selection theory. Females, as described by the original sexual selection theory, are not supposed to mate when already pregnant. Yet, the reality of female choice in mating selection is often much more complicated than the orignial proposed model.

Scientific background
Darwin originated the idea of the sexual selection. He described sexual selection in The Descent of Man as the "struggle between the individuals of one sex, generally the males, for the possession of the other sex". That is, conspecific males will compete with conspecifitc males in order to gain access to females to mate with. This competition might include male-male fighting or a display of aesthetics (e.g. a peacock's tail feathers) to indicate health.

A female may choose a male to mate with who has brighter colors, a bigger size and more aggression to give her offspring a better chance of survival. If the male can expend energy on elaborate asthetics, this shows he has the health and resources to spend on these "expensive" (energy, resource consuming) traits. If he is bigger and is able to dominate other males in competition this shows that he is stronger and more able to find resources for himself or possibly fend off other males and predators to protect the female or her offspring. As Nelson describes the theory "Because males typically compete for females, they are usually bigger, more colorful, and more aggressive than females"  Therefore, sexual selection serves as  a "subcategory" of evolution. Organisms will mate with other organisms that have traits that are advantageous to their reproduction. These "better" traits are then passed on through their offsprings who will then continue the cycle of choosing mates with good traits. This is also refered to as the Good Gene Hypothesis.

History
Darwin was the originator of the Sexual Selection Theory. A large part of the sexual selection theory is the concept of female mate choice. It has been often pointed out that Darwin's description largely reflected the time that he lived in. The sexual selection theory is visibly reflective of human white upper middle-class Victorian courtships of Darwin's time. As Fausto Sterling, Gowaty and Zuk describe his scientific writing "After taking in the brilliance of the man and his presentation, the modern reader next notices how embedded Darwin's writings are in the language and value systems of Victorian England". Similarly Lewontin describes Darwin's theory in Biology as Ideology as:

"What Darwin did was take early-nineteenth-century political economy and expand it to include all of natural economy. Moreover, he developed a theory of sexual selection in evolution...in which the chief force is the competition among males to be more appealing to discriminating females.  This theory was meant to explain why males animals often display bright colors or complex mating dances.  It is not clear that Darwin was conscious of how similar his view of sexual selction was to the standard Victorian view of the relationship between middle-class males and females.  In reading Darwin's theory, one can see the proper young lady seated on her sofa while the swain on his knees before her begs for her hand, having laready told her father how many hundred a year he has in income"

It is certainly useful to understand the historical context of where the concept of female choice originated from. It helps describe why the writings on female mate choice has often excluded important factors that contribute to the choice. In this case, it is most likely because of the society that Darwin lived in which influenced him to view animals in relation to how he viewed human mating. His views of course, (it is pretty much impossible for a scientist to seperate the culture they live in from the science they conduct) influenced how he conduced and wrote about his research. Also, many scientists did not take female mate choice very seriously, they either did not notice it or described female mate choice that did not fit the Darwin's sexual selection theory as an exception. Darwin's theory was widely accepted as completely accurate until fairly recently when it became apparent that this explanation did not explain the complexities of female mate choice in the natural world in all cases.

Debates
Some scientists interpret the expansion of Darwin's original sexual selection theory as an unwelcome, unscientific backlash given by people (usually feminists) who have an agenda to empower women through scientific explanation. It is true that female mate choice has traditionally been depicted as passive in evolutionary biology. This passivity as described in the natural world has been used to justify a natural passivity in human women which has resulted in problematic explanation of human women's essential nature. Thus, some scientists think that these new explanations are an uncritical response from people trying to analyze the natural world to further agendas for human women empowerment. Fausto-Sterling, Gowaty and Zuk describe this very well:

"For a long time, and still to some extent today, students of human behavior used animal studies to validate assumptions about human sexuality. For example, male dominance was once thought to structure the societies of primates such as African baboons. Females were believed to follow meekly after males, who struggled with one another for leadership and mates. Similarly, scientists attributed the evolution of striking weapons such as antlers or huge canines to male competition, with the female passively accepting hte winner of the tournament as her mate. Based on such examples, a model of human behavior driven by male competition, male power plays, and often male violence seemed like a natural (in many sense of the word) conclusion."

This expansion of Darwin's original theory in a some-what radical new was seen as unwelcome by some. This expansion began mainly because of the new inclusion of women to the field of animal behavior in 1970. Again, Fausto-Sterling, Gowaty and Zuk describe this new perspective well:

"Over the last decade and a half, however, ideas about animal sexual behavior and the evolution of sexual differences have undergone a revolution. During the 1970's women flooded into the field of animal behavior-especially the study of primates. these new field workers emarged during the second wave of feminism. The new feminist revolution helped open once-closed laboratory doors to women...The new feminism also gave the a new way of viewing the world. For one thing, they started carefully watching the behavior of female animals in the field-with astonishing results. They found, for example, that female kin groups are responsible for determining much of the social lives of baboons...It is possible that their priori notion about sex roles hindered their abilities to observe. It's not the feminists who are blind to the scientific truth. Rather their male-biased predecessors made one-sided observations which led them to lopsided accounts of sexual difference "

Some in evolutionary biology believe that the expanded theory of sexual selection that focuses on female mate choice is incorrect science done to further a political agenda (by feminists), while other believe that it is just expanding a theory that needs expanding, scientifically.

Joan Roughgarden believes that the version of sexual selection given by Darwin, needs to be thrown out and completely re-thought. She believes it promotes "genetic classism" and should be radically re-considered. Rougharden writes "I conluded that Darwin's sexual-selection theory was completely false and needed to be replaced by some new and equally expansive theortical systmed". Her radically new view is called social selection and includes new ways of including female mate choice.

Author
Sarah Adelaida McIntire

Contributors
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