Saturday, 25 July 2015

Make like a snake...

Hemel (BMT): Small, soft, vulnerable creatures that take on the appearance of something far more menacing are right up there in my estimation. Destined to be winged and free, moths and butterflies first have to survive the perilous larval stage. This is essentially a few weeks spent as a soft, slow-moving sausage surrounded by sausage loving predators! Any strategy which improves its chances of survival is most definitely a good one. And, pretending to be a snake, poisonous venom assumed, is about as good as it gets.

I was really chuffed to find one of these plucky snake imitators this week at Roughdown Common. I have been hoping to spot one for the last couple of years, obsessively checking patches of Rosebay Willowherb for Hawk-moth species. In fact, I found this chap climbing a stem of Agrimony whilst nibbling on overlapping Hedge Bedstraw! Some literature suggests that both species of Elephant Hawk-moth larvae feed on the Willowherb. However, the less common of the two, the Small Elephant Hawk-moth (Deilephila porcellus), the one I’d found, actually prefers Bedstraws (Gallium sp) established on nutrient poor grassland, like the chalk-based habitat at Roughdown. Superb! I was just happy to have finally found one.

I had to improvise a bit with the photographs. As I was setting up, the larva dropped to the ground and was instantly lost in the undergrowth. I carefully encouraged it onto a leaf, took a few photos and then put it straight back. The head has the incredible eye-like markings on the top. When alarmed, the larva retracts its long nose/mouth parts or trunk (from which its name is derived) and rears up like a snake, ready to strike. Very convincing it is too!

The images below feature the Small Elephant Hawk-moth adult, trapped and photographed at Roughdown Common, on 11th June. It could well be the parent of the larva.

The front end!

Side view [Left: larva/caterpillar, approx 4-4.5cm; Right: imago/moth]

Above [Left: larva/caterpillar; Right: imago/moth]

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