Originally posted by Shaggy Hiker


This is not the same as the peacock, or the grackle, where the display item (tail feathers) has no known purpose other than to show off to other members of the same species.
When peahens mate with peacocks who have larger 'eyes' on their tail feathers, the eggs turn out to be stronger, and the offspring also have the larger 'eyes' on the tailfeathers.

Fine and good.

You're a fish biologist, do crabs fall under your purview? Have you studied about the Heike crabs? It also features in Carl Sagan's "Cosmos". Some heike crabs had a formation on their carapaces that resemble the face of a samurai warrior, and in their superstitious beliefs, they would not to eat such a crab. Instead, they threw it back into the sea. Since this has been going on for a couple hundred years now, you have almost all of the Heike Crab's with a formation on their carapace.

The samurai-heike-crabs were selected and females preferred that.

What I'm trying to get at is, it does not mean that the diversity of all species arose from female preference only. Over time, different entities found different paths, they developed different appendages, different physical appearances. Out of necessity most likely, and this is what the females would further propagate in the preferential treatment they'd mete out.

In other words, it's more cyclic.