Country diary: a dowdy female with the vapours gets male moths a-flutter

Langstone, Hampshire: Potential mates can detect the emergence of an adult vapourer moth from miles away

It was impossible to miss the rusty tussock moth (Orgyia antiqua) caterpillar foraging on my raspberry bush. Its body was dotted with orangey-red pinacula, wart-like growths sprouting clusters of pale lemon hairs. It had two bristly black antler-like protrusions at the front of its head, and a tail-like projection from its rear. Along its back four sulphur-yellow dorsal tufts stood proud, like the bristles of an interdental toothbrush. Measuring it at 25mm in length, I could tell it was a female, as males reach a maximum of about 15mm.

These caterpillars are polyphagous, feeding on a wide range of deciduous trees and shrubs, so I potted up a selection of raspberry, blueberry, hazel and birch, and introduced her to a rearing cage. After five days of feasting, she stopped eating and spun a cocoon on the underside of a hazel leaf. Over the course of a week I squinted through the web of silken threads, watching the silhouette of her larval body melting and morphing into adult form.