Sexual selection, first proposed by Darwin himself in this case: he thought peahens preferred peacocks with bigger tails, and so bigger tails evolved, regardless of expense in fitness.
This isn’t an explanation until it can explain why peahens prefer peacocks with bigger tails. That’s what the signalling hypothesis is for. I don’t see why these are considered competing hypotheses.
Sorry, should have made that an independent comment, not really an answer to anything in this thread. Just a pet theory brought to mind by all this talk of peacocks and signalling. Cats threaten each other with a toneless sound of rushing air, and and are afraid of high-powered mechanical devices that produce a version of the same effect.
A surplus of resources is one thing that can be signaled, and resistance to parasites is another. They both involve signalling, but these ideas are a bit different from each other—and from sexual selection, which can magnify a wide range of “fashionable” traits.
Of course those things are different from sexual selection. Comparing a trait that can be signalled, to a mechanism by which traits can be magnified, is a type error.
I’m not saying that “sexual selection” and “costly signalling” are the same hypothesis, I’m just saying they aren’t competing. One attempts to explain how a trait gets magnified, the other attempts to explain why.
It looks as though the post you were responding to was wrong to treat these as incompatible hypotheses.
No doubt, peackock tails are magnified by sexual selection, costly and illustrating parasite resistance. However, though compatible, these explanations do compete with each other a little—for example, when explaining particular features of the tails.
This isn’t an explanation until it can explain why peahens prefer peacocks with bigger tails. That’s what the signalling hypothesis is for. I don’t see why these are considered competing hypotheses.
Do you suppose a cat’s hiss tells another cat something about strength and fitness via lung-power?
That could explain their fear of vacuum cleaners and blow-driers.
I don’t suppose that, and I assume you don’t expect me to suppose that, but I don’t know what you’re trying to tell me.
Sorry, should have made that an independent comment, not really an answer to anything in this thread. Just a pet theory brought to mind by all this talk of peacocks and signalling. Cats threaten each other with a toneless sound of rushing air, and and are afraid of high-powered mechanical devices that produce a version of the same effect.
A surplus of resources is one thing that can be signaled, and resistance to parasites is another. They both involve signalling, but these ideas are a bit different from each other—and from sexual selection, which can magnify a wide range of “fashionable” traits.
Of course those things are different from sexual selection. Comparing a trait that can be signalled, to a mechanism by which traits can be magnified, is a type error.
I’m not saying that “sexual selection” and “costly signalling” are the same hypothesis, I’m just saying they aren’t competing. One attempts to explain how a trait gets magnified, the other attempts to explain why.
It looks as though the post you were responding to was wrong to treat these as incompatible hypotheses.
No doubt, peackock tails are magnified by sexual selection, costly and illustrating parasite resistance. However, though compatible, these explanations do compete with each other a little—for example, when explaining particular features of the tails.