Tricky Magic Traits

I was "thumbing" through my favorite eco-evolution blog and read the post on magic traits. "Magic" traits? What on Earth (Ocean) would provoke someone to call a trait magic? thought I. I read on.

Magic traits, which is now a published term, are traits under environmental divergent and sexual selection. For example, if nature is "pressuring" fish to evolve wider mouths, and the females are also really diggin' on the wide-mouthed males, not only do the males grow bigger and stronger because they can fit more in their pie holes but they get to reproduce more because the females find them more attractive. This causes them to rapidly evolve, just like magic! Recently, X. Thibert-Plante and S. Gavrilets published something about how this occurrence, once thought rare, is perhaps actually the norm:

"...certain traits that are under direct natural selection are more likely to be co-opted as mating cues, leading to the appearance of magic traits (i.e. phenotypic traits involved in both local adaptation and mating decisions)."

"Multiple mechanisms of non-random mating can interact so that trait co-evolution enables the evolution of non-random mating mechanisms that would not evolve alone."

(If you understand this last statement, please enlighten me. I put it in here so someone can explain what s/he thinks it means.)

If the traits change quickly, soon enough the divergent trait will become the normal trait. How do females know when selection is no longer divergent? Do they guess based on the number of males they've encountered recently? Obviously I should read the paper, and when I do, this post will likely change.
Another thing: Are these fish evolving the ability to evolve faster? 

These sorts of findings are what make the study of evolution so attractive to me. Nature is so dynamic. It has so many hidden devices that make it resilient, make it adaptable, make it work. Humans will never come close to recreating such compatible complexities.

One of the more interesting images from a Google image search 

on "magic traits." Maybe white Siberian tigers are evolving magically?

Maybe they are magically evolving into zebras. 
Photo from fubiz.net. Art by Andrei Clompos.