Monday, August 06, 2007

From This to This

I still think it's surprising that these caterpillars - -

turn into these moths:

They are cinnabar moths. These live near Tenby, which is where I took their photographs. The caterpillars eat ragwort, which is poisonous, and absorb the poison, so birds quickly learn that it's not a good idea to eat either the caterpillars or the moths.

It's this kind of thing that lends weight to the Intelligent Design theory. How clever of God, its supporters argue, to invent this. The caterpillars even have that yellow-and-black not-good-to-eat signal which is also worn by wasps and bees and other insects.

Actually, I find it easier to believe that it all came about by evolution. Those caterpillars which ate a poisonous plant, and didn't die, and happened to be a bit black-and-yellow-stripy, just did better, survival-wise, than the ones that either ate the poisonous plant and snuffed it, or turned out to be brown with BIRD FOOD written on them in big letters. And because they survived, therefore the next generation were even more poison-absorbing and stripy.

But if God designed them, I find myself asking WHY? And what was the conversation down the pub later?

GOD: "I've done the moths now. Most of them, anyway. The cinnabar moth caterpillars have black and yellow stripes, so the birds will know not to eat them, because they absorb the poison from the plants they eat. Clever eh?"

GOD'S MATE JEFF: "So what do the birds eat, then, if they can't eat the caterpillars?"

GOD: "Errr - - well, I haven't finished the birds yet. Worms, I expect."

GMJ: "So what have you got against the worms?"

GOD: "Pardon? Oh, I see what you mean. Well, nothing, really. But they're not poisonous."

GMJ: "Why not?"

GOD: "They're just not, that's all. The birds have to eat something, don't they?"

GMJ: "So you prefer caterpillars to worms? You seem to be giving the caterpillars an unfair advantage."

GOD: "Well, no, not really. And there are other caterpillars which aren't poisonous. The birds can eat those as well as the worms."

GMJ: "So you're basically giving cinnabar moths preferential treatment?"

GOD: "Look, I've had a very busy day and I've got the Great Plains of Africa to do tomorrow. Drink your pint and shut up."

Hurrah for Charles Darwin, says I.


Blogger John said...

bugger the catapillars, that plant's amazing, one minute all yellowy green, the next a blaze of pinky purple - eat your heart out Almighty One.

6:33 pm  
Anonymous Anonymous said...

I agree with John - wow!

6:58 pm  

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