I’ve always felt the Fisherian runaway hypothesis begs the (second order) question:
The first order question (for the scenario here) is—Why don’t the male bird head plumage continue to grow indefinitely longer from generation to generation? This one is easy. At some point the plumage would become so impractical as to make mating impossible.
The second order question is harder: Why is it that some species get away with remarkably impractical features (the peacock comes quickly to mind), while other species appear to be pretty close to a local maximum in adaptation?
I suppose that a scarcity of predators and a generous environment ought to be part of the story for the most flamboyantly maladaptive species. But has this been empirically verified? And are their other considerations at work?
I’ve always felt the Fisherian runaway hypothesis begs the (second order) question:
The first order question (for the scenario here) is—Why don’t the male bird head plumage continue to grow indefinitely longer from generation to generation? This one is easy. At some point the plumage would become so impractical as to make mating impossible.
The second order question is harder: Why is it that some species get away with remarkably impractical features (the peacock comes quickly to mind), while other species appear to be pretty close to a local maximum in adaptation?
I suppose that a scarcity of predators and a generous environment ought to be part of the story for the most flamboyantly maladaptive species. But has this been empirically verified? And are their other considerations at work?
That sounds plausible, but I’ve not looked into the empirical research on that topic so I can’t tell you much more!