Saturday, 28 May 2011

Pass the pepper, we're 400-up

It's nice to celebrate this 400th post on MM with an old and attractive friend: the illustrious Peppered Moth which has played a major part in Darwinian theory. Google it, and you enter a world of competing ideologues, one lot as determined to use the moth to discredit the principle of natural selection as the others are certain that it provides proof of it.

I know where I stand; alongside Darwin. But I'm happy just to enjoy the beauty of the moth - look at the lovely salt-and-pepper marking and those antennae, right - and take pleasure in the ever-growing ascendancy of the standard form shown here. When I was a boy, the much duller melanistic version held sway in smoky Yorkshire. The whole Darwinian business involves the shifts between the two forms as their environment changed and camouflage became ineffective. A standard Peppered moth is hard to spot on a clean-barked birch tree or unpolluted walls. The melanistic version hides equally well on grubby foliage or soot-blackened stone. They're not so good for the standard, as shown - I can see you! - below.

The surgeon Sir Cyril Clarke did an appealing piece of research which correlated the decline of the melanistic Peppered in the UK with the increase in the number of centenarians (helped by an obliging Buckingham Palace and its records of Royal telegrams on 100th birthdays).
I have had both forms here since I started light-trapping in 2004 but have not seen a melanistic one for some years. Thanks to Butterfly Conservation for this piclet of one, left.

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