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.
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.