In his youth, Charles Darwin also had an inordinate fondness for beetles. Late in life, he wrote in his autobiography:

No poet ever felt more delighted at seeing his first poem published than I did at seeing, in Stephens’ ‘Illustrations of British Insects,’ the magic words, “captured by C. Darwin, Esq.”

The Stephens in question was James Francis Stephens, a top entomologist, whom the young Darwin had visited in early 1829, later writing to his cousin:

On Monday evening I drank tea with Stephens: his cabinet is more magnificent than the most zealous Entomologist could dream of: He appears to be a very goodhumoured pleasant little man.

The momentous event of Darwin’s citation in Stephens’ illustrious journal occurred a few months later, 180 years ago today, on 15th June, 1829.

This Saturday’s Guardian magazine had a great set of Martin Parr photos. They also published them and some of his other photos online. One of the online-only photos grabbed my attention for obvious reasons:

Darwin’s beetle collection, Cambridge University Museum of Zoology.

Meadow Brown butterfly [Maniola jurtina]

More of this afternoon’s garden snaps here.

Female Orange-tip Butterfly [Anthocharis cardamines] sitting on one of its favourite food plants, Lady’s Smock / Cuckoo Flower [Cardamine pratensis]

Fantastic camouflage. As my partner Jen remarked, it looked just like a dollop of bird poo.

I love my macro lens!

The interview explains how the experimental weaknesses were blown out of all proportion by creationists, who saw the flawed experiments as somehow disproving evolution. It goes on to explain how Majerus has painstakingly repeated Kettlewell’s experiments, having carefully removed the flaws, and verified Kettlewell’s original findings. It also makes a lie of the claim often made against evolution that it is unscientific because it makes no predictions by predicting that industrial melanism in moths will continue to decline in the UK, now that the air is a lot cleaner, whereas it will start to rise in countries where pollution is on the rise, such as China and India.

A fascinating programme. (The second half contains an interview with the recent winner of the Nobel Prize for Medicine, Sir Martin Evans, which is also pretty interesting.)

Is it a twig, or is it a caterpillar?

Isn’t Natural Selection utterly amazing? I would never have spotted this creature had it not, rather stupidly, taken up residence on a fence, rather than the branch of a tree. As a rule, fences tend not to have twigs.

The delay in posting this photo was due to my unsuccessful attempts to identify the species in question. My best guess at the moment is that it is the caterpillar of the world-famous peppered moth—which would be rather cool. Apparently, it isn’t just adult peppered moths that come in a variety of camouflaged colours, hence my uncertainty.

I will get to the bottom of this one.

See also: Books: Of Moths & Men

Postscript (21-Oct-2007): I eventually managed to find the excellent UK website Eggs, Larvae and Pupae of Butterflies and Moths, which confirmed that my find was indeed the caterpillar of a peppered moth. The website took me so long to find because I had been searching for ‘UK caterpillars’, but the experts tend to refer to them as pupae!

Apparently, every time male diving beetles evolve better suction cups on their feet to hold on to females during mating, the females evolve countermeasures to decrease the effectiveness of the suction cups. This is because the optimal time, length or the number of matings is not the same for males and females.

Who says romance is dead?

Then I vaguely remembered reading about such behaviour somewhere in Darwin’s correspondence. A quick search later, and there it was. Darwin had written to the Gardeners’ Chronicle magazine to elaborate on earlier observations made by other readers:

Darwin, C. R. to Gardeners’ Chronicle, [16 Aug 1841]

Perhaps some of your readers may like to hear a few more particulars about the humble-bees which bore holes in flowers, and thus extract the nectar. This operation has been performed on a large scale in the Zoological Gardens […] I observed some plants of Marvel of Peru, and of Salvia coccinea, with holes in similar positions; […] I first noticed them a week since, when, from the brown colour of their edges, they appeared to have been made some time before. The beds of Stachys and Pentstemon are frequented by numerous humble-bees of many very different kinds; at one moment I saw between twenty and thirty round a bed of the latter flower; they fly very quickly from flower to flower, and always alight with their heads just over the little orifices, into which they most dexterously insert their proboscis, and in the case of the Pentstemon, first into the orifice on one side and then into the other, so that they thus extract the nectar on both sides of the germen. […]—C.

It’s crane fly season here in West Yorkshire. Last week, we were suddenly inundated with them. One week there wasn’t any sign of them, the next they were all over the place—particularly in the evenings.

I didn’t know, until I looked it up, that crane flies spend most of their lives underground in their larval forms, which are known a leatherjackets. I knew that leatherjackets were very common round here, and are a favourite food of the local crows (particularly the rooks), but I did not know that leatherjackets transform into crane flies. You learn something every day.

I naturally supposed that crane flies emerge en masse to increase their chances of encountering a mate—which I still guess is right. But then I had another thought: emerging en masse will also give the individual crane flies a better chance of avoiding being eaten by predators: plenty more fish in the sea, so to speak. And then it occurred to me that they emerge in early September, which is about the time that swallows traditionally start heading south for the winter. Could the timing of the crane flies’ emergence in September be an adaptation to avoid being eaten by swallows?

If so, it isn’t a 100% reliable strategy. One evening last week, a family of swallows spent a good half-hour hunting around the west-facing eaves of my house. I initially mistook them for local bats—I had not seen swallows that close to the house before. I wonder if they were hunting crane flies, which appear to be attracted to the residual warmth of the building after sunset.

See also: Swallows preparing for migration

Postscript: Telegraph: Hot weather breeding boom brings invasion of the daddy long-legs