The Vapourer…the name sounds like some kind of superhero. I see a mysterious figure surrounding by mist and lighting that exudes steam to destroy the enemy. But let me stop here before this turns into a fantasy blog! The vapourer (Orgyia antiqua) is actually a day-active moth and as a caterpillar it is quite conspicuous and beautiful.
I encountered this caterpillar two years ago when walking through a nearby park during lunch break. I found it a very funky caterpillar and had to look it up as soon as I got back to my desk. Because of its funkyness, it was easy to determine. Had I found the female adult, I wouldn’t even thought it was a moth! Adult male and female vapourers look very different (sexual dimorphism). The male is a rusty-brown coloured moth with a white dot on each of the wings. This is why the moth is called ‘witvlakvlinder’ in Dutch. The female however, doesn’t even have wings! It looks like a fat, gray worm with vestigial wings. When fertile, the female sits on her cocoon and spreads out pheromones to attract males. Males smell this from miles away with their feathered antennas and come flying in to mate with her. Afterwards, she lays her eggs and soon after dies. Males also die soon, as adult moths don’t eat, but rather live off the reserves they accumulated as a caterpillar. The eggs overwinter and hatch early spring. As the larvae spread out on threads into the wide open world, they look a bit like mist, hence the common English name ‘vapourer‘. The Latin name Orgyia has to do with the way the adult males stretch their legs forwards when resting. Antiqua means ‘old, old-fashioned’ after the adult female who ‘stays at home’. Interesting how in different languages, different aspects of behaviour or looks are used to give a species a name.