Yesterday my partner and I were sitting by Caldecotte Lake, when she pointed out a “huge caterpillar” on willow-herb a few feet away over tangled waterside vegetation.  With close-focused bins I quickly confirmed it as an Elephant hawkmoth, and was pleased she’d spotted it as she’d been wowed finding an adult in her garden a few years ago.  Though dark, it was lighter and more strikingly marked than the typical velvety black – sadly an exact match for tarmac – seen by most who encounter these larvae when roving pre-pupation.

I then launched into some “mansplaining”: eyespots, head, mandibles, horned tail – that sort of thing.  However, her responses – in particular her efforts to describe its markings – made little sense to me.  If there is a goddess of effective communication she was clearly struggling, but disagreement would only have spoiled the moment.  I wanted to share the pleasure – my sense that in some small corner all’s well with the world – which I have always had seeing a caterpillar peaceably munching its food-plant.  A Kingfisher shot past, a Heron settled in a dead tree.

Eventually:
She:  “What’s that dark thing a bit above it?  Is it a dead leaf or something?”
Me:   “What dark thing?  The only dark thing is the caterpillar.”
She:  “My caterpillar’s not dark at all”.

Her caterpillar was in fact about six inches lower, bright apple-green and equally large, though I’d entirely failed to see it (I plead intervening foliage and a slightly different sightline).  It was of course a second Elephant hawk.  Though the adult is pretty constant, the larvae have a wide spectrum of colour variation, and this was clearly “extreme green”—more like an Emperor or Privet hawk, in fact.

Yet it’s likely both larvae were from eggs laid by one female, and mated by a single male.  A genetic conundrum almost as interesting as how two people can spend twenty minutes thinking they are discussing the same object when they’re not.

Chris Coppock, 27 August 2020

[Photo of Elephant Hawkmoth caterpillar, Deilephilia Elpenor, by Julian Lambley, Old Wolverton Mill, 11 September 2016]