Challenge to sexual selection in peacocks...?

http://webcache.googleusercontent.com/search?q=cac...

There are lots of things lumped under the term "sexual selection." It could mean female choice, or it could mean male-male combat for the right to mate, or it could also mean female-female competition to evolve larger body size so as to carry more eggs, without any combat. Male combat often leads to weapons (antlers and horns) and/or large body size and sexual dimorphism. Female competition, in the absence of male combat, will lead to females being larger than males.

I have always been skeptical of the claim that female choice is solely responsible for the elaborate ornamental feathers in male birds. In reality the gaudy male feathers are used to identify a bird's species status (hey, I am a male CARDINAL, or I am a male MALLARD), because it is a major penalty to one's individual fitness if one crosses species boundaries and produces hybrids that are ecologically maladaptive because of a less than optimal genotype due to mixing of two incompatible genotypes. Most researchers, however, assume that the gaudy feathers advertise the physical health of the male bird. The current study pretty much falsifies that feathers are indicators of health.

Another assumption that Darwin and most other scientists made without any investigation is that the gaudy feathers of the peacock renders it more susceptible to predation. That is a fundamental but unfortunately false assumption that then lead to another assumption of how these feathers could have evolved: female choice. The current study questions, if not falsifies this fundamental assumptions that male peacocks are more vulnerable to predation or that females pick males on the basis of their tail feathers.

The take home lesson is that many of the theories we hold as self-evident truths may actually be based on unwarranted and unverified assumptions. Given the fact that peahens are smaller, and more cryptically colored but they fell victim to predators more often, perhaps the large tail feathers and the eyes spots of the peacock's tail have an anti-predatory function, similar to the large eye spots found on the wings of some butterflies. These eye spots and the oversized tail feathers may fool predators into believing that the male peacock is a much bigger animal that it really is. Therefore, even without female preference for the eye spots, they will evolve to help the males avoid predators. This is not the only unverified assumption floating around in the scientific literature. Another assumption that is widely held is that coral snakes and their presumed "mimics" have aposematic coloration. No one has ever observed a predator avoid the color of the coral snake "mimics" and yet there is no shortage of observations that hawks will eat the dangerous coral snakes themselves, not just the "mimics." In fact, there is also observation that the "mimics" are actually cryptic in their natural surroundings, even though they look conspicuous in an empty glass cage inside a university laboratory. The coral snake mimicry hypothesis and the female choice hypothesis of male peacock feathers have been exposed to be what they really are: unverified hypotheses based on unverified, albeit seemingly logical, assumptions.

Sexual Selection In Peacocks

Cool, but I am wondering how close to wild stock the birds in the study are. That can make a HUGE difference in the results. The fact that an earlier study found opposite results makes me wonder even more. Especially since in the last 10 - 20 years are so, there have been many color variations bred, many without any eye spots...which if they come from a breed with fewer eye spots, the results may easily be the opposite of wild stock.

So if these researchers are correct, then where does the pressure come from? Male to male selection as territorial display? Possible

Also of course predation rate in the situation they were in is no different. Peacock adults do not suffer a high predation rate when not in the wild.

You have to remember that the study was NOT conducted in the wild. Thus may not be in the least valid....it may be....but no one can say.

I have the pdf of the article in question:

Actually 2008

Peahens do not prefer peacocks with more elaborate trains

Mariko Takahashi∗, , , Hiroyuki Arita†, 1, Mariko Hiraiwa-Hasegawa‡, 2, Toshikazu Hasegawa∗

Can send it on.