Riddles of Mother Nature

Well this was a weird question I had when I was on a trek in konkan. A butterfly which falls into the buck-eye species are found in plenty there. Please see pic

So this is how these butterflies look like, an the reason behind these eye-like designs on their wings is that they tend to confuse their predators. Now this is one of the many creations of evolution. And such tricks do still work in nature and hence the genome of these species perpetuate and we are seeing these species thriving. So this triggered a question in my mind.

There are several protocols followed in nature which convey specific messages to their predators, e.g.
1) bright colors: I am poisonous... Don't you dare eat me.
2) eye-like, head-like designs: I am trying to fool you by misplacing my eyes/head

Besides these common signals, there may be many more tactics of self defense. Naturally these tactics didn't suddenly come out of the blue. It took several generations of species and several mutations and sub mutations to come to a exactly working combination. So we can assume that the poison arrow frog (see the image) had several mutations tried out before settling down to a bright colored skin which was recognized amongst the group of his predators that its not safe to eat.

Now here goes my confusion/question/anomaly whatever you may call it.
How does the frog informs his habitat that bright colored skin means "Dont eat me, you will die", because even if the predator eats him both of them die and invariably the frogs bright color did not help him and neither did it helped his mutated genes pass over to the next generation, so that his decendents may wear the same skin. If we think the other way round, How did his predators come to know that this new design is what we should not eat. Cos any way post eating, they are dying, forbidding their learnt lesson to be passed on to their descendents in form of mutations.

So in a broader meaning, my question is : How does a mutation in a specie attain equilibrium with its habitat and what is the process of the same to avoid failure of the mutation?