Steppingstone to evolution secret ?!

Just read the article – “Butterfly unlocks evolution secretover at BBC.

The article does not throw enough light on the background of the theories and on how the observations exactly connect with them. Over excitedly, I was looking for the answer to the basic question “Why ?” in the article and was sorely disappointed. But It does cover about speciation and specifically due to geographical differences for reasons that would become obvious after reading the following sentence.
If similarly closely related species are living side-by-side, the researchers noticed, they frequently look strikingly different – their “teams” are clearly advertised.

This has the effect of discouraging inter-species mating, thus encouraging genetic isolation and species divergence.

This process, called “reinforcement”, prevents closely related species from interbreeding thus driving them further apart genetically and promoting speciation.

Well eventhough this sort of thing is intuitive, IMO, knowledge is nothing but memories digged out from our own mind, hidden until the right moment, felt in a flash as intuition ! Before i become more philosophical, just read the article. Nothing mind-bending really but definitely worth the time.