Thursday, 28 May 2015


My title today is meant to be a sneeze - maybe I should have added 'Bless you!' - because this morning the year's first Peppered Moth was stylishly perched in one of the eggboxes. This is a nice coincidence because last week I had an email from Cornell University Press in the States saying that they were potentially interested in using a picture from one of the many previous mentions I've made of the Peppered Moth here.

I didn't ask the subject of the book when replying to say Yes, but I am sure the reference will be to the Peppered's hallowed place in the science of genetics, through the rise and fall of the melanic, or dark, version of the species and its relationship with the parallel rise and fall of pollution.  This was most entertainingly illustrated by the great entomologist and doctor Sir Cyril Clarke, who famously plotted a graph showing similar curves for (a) the decline of the melanic Peppered in the UK and (b) the rise in centenarians here during the same period, when much of the dreadful, unhealthy legacy of our industrial past was at last brought under control.

Scientifically, the Peppered plays a wider role as a striking and easy-to-understand example of Darwin's natural selection in action, though you will find many a furious counterblast to this from Creationists online. My pictures show, at the top, today's Peppered Moth and below, the picture of both types when they flew in together on the same night in 2013 - the one which Cornell UP may use. I hope they do.

The other feature of this moth which I've noticed over the years is how neatly it positions itself in the eggboxes which happened again this morning - the wings conforming almost exactly to the angles of the cone. This has been taken in previous years to the lengths of the moths sitting on the barcodes which have a vaguely similar black-and-white pattern to their own. The point about the correlation of melanism with pollution, I should have explained earlier, is that in sooty areas the dark moth was less likely to be predated than the standard, peppered one which conversely survives better in cleaner surroundings where the melanic moth stands out as a dark splodge.


Katie (Nature ID) said...

Hello, Martin. I find this post rather interesting, because about 15-20 years or so ago (when I was fresh out of college having majored in entomology and was working at a prominent natural history museum here in the States in order to write several peer-reviewed papers from a long-term moth study) when I read another paper documenting the biased and faulty methods of the research you mention. Essentially, the rebuttal authors stated the results, which had already entered into legend (and textbooks!), were completely bogus... akin to starving praying mantid females in the lab before introducing a male to mate - of course she would eat her mate, because no other food was offered, which has given the female praying mantids a bad rep (apparently in the wild, the females do not generally eat the males). It's been so long that I forget the details of the peppered moth confusion. I wasn't aware that this is somehow tied to the debate between evolutionists and creationists. Hmm...

Katie (Nature ID) said...

I'm glad you wrote about the peppered moth, Martin, because otherwise I may have never looked into the evolution vs. creationism debate. Honestly, I had no idea Ted Sargent's critiques from his 1998 paper were being used as propaganda by creationists. Coincidentally, my own mentor died unexpectedly before we could finish publishing analyses from her moth study (like Michael Majerus)... which, out of grief, caused me to stop studying moths altogether, hence why I haven't kept current over the past 15 years. Thanks.


MartinWainwright said...

Hi Katie

Many apologies for the delay in replying - my granddaughter has kept me busier than usual. You're quite right to be cautious about the Peppered Moth as your research online shows. I'm very well aware of my own scientific limitations (failed physics-with-chemistry long ago) so what I think isn't of any use to the debate, but I read an interesting piece by a Milton Wainwright (hooray, though no relation so far as I know) from Sheffield University which is here and the website hosting it seems wholly transparent about being Christian with traditional beliefs based on the Bible but also concerned to treat science dispassionately. I think it makes a good case for not getting over-excited about the Peppered Moth as Darwinian proof, while acknowledging its significance and interest. I think I find it interesting mainly as an example of natural selection in action (the predation of the 'wrongly' camouflaged types) which - I think - accords with Darwin's description of the mechanism.

I'm sorry that you suspended your moth studies and I'm very glad you're back in the field. Alas, I don't have the time, stamina or - I have to confess, interest - to amass the data which fortifies good science. For that, you need to follow the real experts on sites such as the Upper Thames Moths blog - But I get tremendous fun out of it and out of exchanges with your good self and others who comment

All warm wishes and sorry again for the delay