25 November 2005

A happy survivor

"All that we can do, is to keep steadily in mind that each organic being is striving to increase in a geometrical ratio; that each at some period of its life, during some season of the year, during each generation or at intervals, has to struggle for life and to suffer great destruction. When we reflect on this struggle, we may console ourselves with the full belief, that the war of nature is not incessant, that no fear is felt, that death is generally prompt, and that the vigorous, the healthy, and the happy survive and multiply."

Charles Darwin, On the Origin of Species


Butterflies with damaged wings are common. Their wings may be damaged by predators, other butterflies during courtship or territorial fights, and perhaps even by strong winds and heavy rainstorms. The ability of butterflies to fly with wings missing chunks demonstrates that their wings are larger than the minimum size required for flight. Although it must be costly to grow larger wings, they are an indispensable safety mechanism. I have written about an example of a similar "over-adaptation" in land snails that can survive without water for periods much longer than they normally experience in the wild.

This Wood Nymph (Cercyonis pegala), with its wings literally falling apart, was a real survivor. Obviously, it had gone thru a lot. But it could still fly and it wasn't done yet. It was nectaring, perhaps to take care of one last unfinished business.

May its genes live long and evolve!

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