Why are many butterflies so colourful?

Answer 1

Butterfly wing colors are functional and are a means of communicating to other members of their species as well as to predators. First, imagine a situation where butterflies of the same kind must find prospective mates. The visual clue of wing color makes that task possible and practicable. If the risk of predation from birds is low then the most pressing task for a butterfly is to find a mate. Another type coloration as in the Monarch butterfly is to warn off potential predators. The butterflies food contains a toxin that is concentrated in their bodies. Predators that eat a Monarch will get sick, remember the color of the nasty bug, and henceforth avoid it.

see: http://www.answers.com/topic/monarch-butterfly-1

Men pass in front of our eyes like butterflies, creatures of a brief season. We love them; they are brave, proud, beautiful, clever; and they die almost at once. They die so soon that our hearts are continually racked with pain.

Philip Pullman

"The Butterfly"

The last, the very last,

So richly, brightly, dazzlingly yellow.

Perhaps if the sun's tears would sing

against a white stone. . . .

Such, such a yellow

Is carried lightly 'way up high.

It went away I'm sure because it wished to

kiss the world good-bye.

For seven weeks I've lived in here,

Penned up inside this ghetto.

But I have found what I love here.

The dandelions call to me

And the white chestnut branches in the court.

Only I never saw another butterfly.

That butterfly was the last one.

Butterflies don't live in here,

in the ghetto.

Pavel Friedmann

The cited reference states that : "The wings of butterflies and moths are decorated with vivid colour patterns that have been shown to function in species recognition, mate choice, camouflage, warning signalling, and in the deflection of predator attack."

Answer 2

because they love the warm sun and they collect nectar