Question

An example of natural selection is the tail of a male peacock. The females of the species choose mates based on the colors of the males’ tail feathers. If females begin using different criteria than feather color when they choose mates, what would most likely happen to the tails of peacocks over time?
increased variation in tail feather color because the selection pressure has been relieved
increased variation in tail feather color because the peacocks try different ways to impress the females
decreased variation in tail feather color because no form of the trait is advantageous
decreased variation in tail feather color because the only reason for variation was selection pressure

Answer 1

The correct answer is the last one: Decreased variation in tail feather color because the only reason for variation was selection pressure.

If the female peacock were to base her selection criteria on something other than the colors of the male's tail feathers, the latter would not play such an important role anymore and therefore there would no longer be the pressure of needing to have the brightest, most variant and vibrant colors. 

Answer 2

The female peacock will be based in her selection no through the color of the tail of the male. So if females begin using different criteria than feather color when they choose mates, the event that ould most likely happen to the tails of peacocks over time is decreased variation in tail feather color because the only reason for variation was selection pressure.