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Appealing Choice

By Erika Lorraine Milam Appealing Choice A book is born from pondering why sexual selection was, for so long, a minor component of evolutionary biology. Erika Lorraine Milam Courtesy of The University Of Maryland I became fascinated by the history of sexual selection during my second year of graduate work in biology. I was drafting a review paper on the evolution of internal reproduction in fishes. The two dominant theories at the time (worked out with in

By | January 1, 2011

Appealing Choice

A book is born from pondering why sexual selection was,
for so long, a minor component of evolutionary biology.

Erika Lorraine Milam
Courtesy of The University Of Maryland

I became fascinated by the history of sexual selection during my second year of graduate work in biology. I was drafting a review paper on the evolution of internal reproduction in fishes. The two dominant theories at the time (worked out with insects) suggested that the insemination of females evolved either because of male-male competition for access to the time and place of fertilization, or because cryptic female choice drove increased competition between males. Who was in charge of the mating game, I wondered, males or females? The evidence for both claims was very similar: the tendency of sexual organs to become more complex over evolutionary time. What differed was the interpretation.

Around the same time, my advisor was consistently vexed by the university’s reluctance to support what it saw as old-fashioned science. At a meeting he had been asked to name even one recent theory developed by organismal biologists that had transformed our fundamental knowledge of life or nature. My answer would have been sexual selection. I thought of it then as a relatively new theory—conceived by Charles Darwin in 1859, yes, but transformed into modern biology only in the mid-1970s—that provided an exciting set of tools for addressing many of the big issues in biological theory, from speciation to the evolution of sex.

Combined, these experiences made me want to know more about the history of sexual selection as an idea, how the theory was entangled in social conceptions of masculinity and femininity, and, perhaps most importantly, how theories of sexual behavior in animals could help us understand what it means (and meant) to be human. Many years later, Looking for a Few Good Males: Female Choice in Evolutionary Biology is my answer—which of course turned out to be far more complicated than I anticipated.

Listen to Erika Lorraine Milam read from her book, Looking for a Few Good Males: Female Choice in Evolutionary Biology

For Darwin, sexual selection served as a naturalistic mechanism explaining why beauty evolved in the animal kingdom and why variations within a species could persist for long periods of time. Sexual selection, he posited, worked according to two mechanisms: male-male competition and female choice. Many zoologists of Darwin’s era dismissed sexual selection because female choice seemed to require a great deal of mental capacity. Could a female bird or insect really compare male mating displays and then choose the prettiest male as a mate? They considered such characterizations of the animal mind to be pure anthropomorphism. Darwin’s theory hit it big only in the mid-1970s, when theoretical biologists like Robert Trivers applied new mathematical explanations of sexual selection to animals as well as people. Critics of sexual selection in this new age of sociobiology attacked accounts of female choice in humans as zoomorphic, contending that far more was involved in human mate choice than simple instinctive preferences and stylized courtship rituals.

Typically, biologists and historians have pinned the blame for the relative lack of scientific interest in sexual selection on the female in female choice, supposing that earlier biologists had neglected the topic because they assumed a negligible role for females in their evolutionary theories of social behavior. As a result of my research, however, I began to understand that female mating behavior had been a topic of immense interest to biologists throughout the twentieth century. In the early decades, women’s choice of marriage partners formed a crucial component of eugenicists’ hopes for the betterment of society. By midcentury, zoologists used female mating behavior as a tool to understand how species become reproductively isolated. Biologists even investigated the courtship behavior of fruit flies to see if female mating preferences for rare males served to maintain the genetic diversity of a population. Yet sexual selection remained a minor component of evolutionary theory for the first two-thirds of the last century. Why? Not because of the agency it imparted to females, but thanks to arguments over animal minds and human instincts—not the female component of female choice, but choice itself.

Since the 1970s, sexual selection has become a cornerstone of modern evolutionary theory, but the controversies are far from over. Knowing the history provides us with an explanation of how and why these controversies persist. Theories of female choice and sexual selection are often as much about what it means to be human as they are about animal nature.

Published by The Johns Hopkins University Press in 2010, Milam’s book had its genesis when she was a doctoral student in the History of Science Department at the University of Wisconsin. She now teaches history of science at the University of Maryland, College Park. Her current project explores theories of human aggression and animal nature in the 1960s.

Comments

Avatar of: anonymous poster

anonymous poster

Posts: 15

January 14, 2011

I have never understood why sexual selection is considered any differently than any other component of fitness. If a male is fleet and catches prey readily, his fitness is high. If he is pretty and females are attracted to him, his fitness is high. What's the difference?
Avatar of: Gunjan Guha

Gunjan Guha

Posts: 1

January 14, 2011

Fitness is also evaluated in terms of biotic potential. How does sexual selection work there?
Avatar of: naomi diaz

naomi diaz

Posts: 17

January 14, 2011

I think fitness is another way to call it. You will notice than the healthiest and prettiest which you can call the most fit tend to be preferred my females. i.e. flies will mate with male flies that have symmetric wings maybe because they are prettiest but also because having symmetric wings is a sing of fitness and agility which indicate good genes and better offspring. This is why I do believe that it requires a great deal of mental capacity for a female insect to deduce this.Just my opinion, I do cancer research, I don't know much about zoology but I love this topic.
Avatar of: Ankur Dnyanmote

Ankur Dnyanmote

Posts: 1

January 14, 2011

It seems that sexual selection is as enigmatic as natural selection. I mean why is it that "we" who are having this discussion here exist and not someone else?
Avatar of: Nirmal Mishra

Nirmal Mishra

Posts: 22

January 14, 2011

Sexual selection seems to have a mental component ,that is, brain development.\nWith the development of neuronal component the choice of males/femeles relied not only on physical fitness, but on other behavioral aspects that females found more sustainable. Fidelity, mutual trust, altruistic behavior also became determinants of sexual selection.\n\nNirmal Kumar Mishra\nRetd. University Professor of Zoology, Patna University, Patna (India)\nJanuary 15, 2011, Scientist.com\n

January 15, 2011

I dont think it needs a great deal of mental capacity for females to deduce the fitness of males(because thats not wat they do).\nImagine a situation where a female arises (by random event) in a population with slight preference towards the males who display the characters (ex. peacock's tail, symmetry etc). These females will have selective advantage over others(since only fit males will be able to display such characters). And then over a period of time you will see most of the females having preferences for these characters (just bcoz they have been selected for it).\n\nHemant S\nDelhi
Avatar of: naomi diaz

naomi diaz

Posts: 17

January 15, 2011

I was just agreeing with the author about the mental capacity. I still do agree it needs some mental capacity to prefer the better fit male because its a matter of intuition and the fact that better fitness means better genes and better offspring even if the female selects by pure instinct, she will still select the male with a higher chance of giving better offspring. That is part of the same natural selection process, to capacitate mates to find the best partner to have better fit offspring for whatever the physical needs in the environmental conditions available at that moment. There are other examples of physical features disappearing when they are not needed anymore, I think that may also have to do with mates choosing to mate with those who lack those physical features. But the same applies with human, most women are the ones who choose the guy who they want to mate with based on good genetics and good physical features, as it would mean smart good looking kids. Now with genetic manipulation we are closer to being able to choose how we want our kids to look.
Avatar of: Richard Patrock

Richard Patrock

Posts: 52

January 17, 2011

My formative years were in the age of strict anthropomorphism. The basic assumption about extrapolation just needed to be offset by caution in its use. I became interested in tool use when I was an undergraduate in the 70's after taking an anthropology course. I was told that seagulls who dropped a bivalve on a rock weren't using tools since they didn't handle the rock. At that time, I wasn't able to articulate why this logic was nuts or even the context for such twisted logic. What struck me at that time and it hasn't left me is that these were people who gained theoretical benefit by simplifying nature into black and white; maintaining man vs. beast as the rule of law. Only man could plan, only man could make decisions, only man could have choice. Animal choice could only follow after knowing they could suffer; after knowing that they had free will. Imagine, bacteria can make choices! Insects use tools! Chimps can speak with their hands!
Avatar of: naomi diaz

naomi diaz

Posts: 17

January 19, 2011

I totally agree with you!! That is why I agreed and believe in the above article. Insects as simple as they look can make decisions as intuitive as they may seem such as choosing the best fit mate to prolong its existence. That is part of the selective nature of life.

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