The lesson that Darwin’s Sphinx Moth teaches writers
I’ve made much over the years of a writer’s peculiar capacity to imagine himself into the consciousness of another human being, to share his feelings, to be able, in a word, to see the universe from another’s perspective. It is thanks to this ability that we are able to write imaginative fictions at all.
Nothing demonstrates this better than a story about Charles Darwin. It begins with his receiving one day a parcel of orchids from a collector who’d scoured Madagascar for new species. Among them was a Star of Bethlehem orchid which possessed an unusually long, and very narrow, whip-like nectary – the vessel at the bottom of which lay the pool of nectar of interest to pollinators. The name of the orchid was Angræcum sesquipedalia. “Sesquipedalian” has long been one of my favourite obscure words; it usually refers to words, and it means polysyllabic, from the Latin which in turn means “a foot and a half long”.
This orchid’s nectary was, in fact, not quite a foot and a half long – but almost. The nectary spur of most specimens ranges between ten and fourteen inches in length.
In the book he wrote about orchids* Darwin describes inserting the tip of a pencil into the throat of an orchid. He then did what writers do – he tried to imagine himself into the brain of a pollinator – in the case of this orchid, a moth. The only means by which a moth would be able to reach the nectar would be if it possessed a tongue at least as long as the nectary. But what moth, even in the fabulous etymological kingdom of Madagascar, had a tongue ten or fourteen inches in length? It was unthinkable.
“Good Heavens,” Darwin wrote to his friend Joseph Hooker, “what insect can suck it?”
But then, as a fictional contemporary of Darwin’s, one Sherlock Holmes, might have said, “when you have eliminated the impossible, whatever remains, however improbable, must be the truth.”**
So Darwin went out on a limb and predicted that a moth would be found on the island with a tongue 14 inches long. It was, as his book set out to demonstrate, an extreme example of the co-evolution of insects and orchids, in which, over countless generations, the insect and the plant evolved the better to serve each other’s needs.
His prediction was mocked by some of his fellow naturalists. It was obvious, they thought, that a tongue that long was simply a physical and biological impossibility. The explanation, they thought, had to lie elsewhere.
Forty one years later, a party of naturalists drawn to the wonders of Madagascar, found a species of Sphinx Moth with precisely the proboscis Darwin had predicted. His exercise in imagining himself into the mind and body of an insect had paid off.
* It bears the cumbersome title, On the Various Contrivances by which British and Foreign Orchids are Fertilised by Insects, and on the Good Effects of Intercrossing.
** Sherlock Holmes in fact only came into existence in 1887, five years after Darwin’s death – but presumably, in the gauzy world of fictional reality his life would have overlapped with the naturalist’s. A Study in Scarlet, the first Sherlock Holmes story, was, in fact, set in 1880.