Driving home late at night, thinking of bed, I caught a flash of movement – a muntjac deer on the verge. I implored it to stay put. Next, a flurry of pale flakes: not snow but moths, illuminated in the car’s beam.
Winter seems an odd time for gossamer-soft, fragile moths. Most insects hide away, or diapause, a process that is similar to hibernation. But for winter moths, Operophtera brumata, now is their peak of activity. Eschewing balmy summer nights has given them an advantage: the night sky is free from hungry bats.
It was a boys’ night out. Female winter moths are flightless, practically wingless, and unable to join this night-time swirling. By day, they often sit on the base of trees, waiting for nightfall, when they crawl upwards, releasing pheromones that attract the males to them for mating.
The next morning the wood was still, except for a small flock of great tits and long-tailed tits flitting among the trees, which was a good sign, for they often feast on these moths. At the foot of an oak, there was a scattering of broken wings.
I scoured the tree trunks, finding centipedes, woodlice and spiders but only one dead female, caught in a web. She was a sorry, slightly soggy, specimen but peculiar with her stunted wings and mottled body, like a strange fluffy grasshopper or stretched spider.
After mating, the females lay their eggs, about 150 of them, on the buds of trees such as apple and oak. Thousands of green, looping caterpillars emerge when the first nascent leaves unfold in early spring – when, with perfect synchronicity, the blue and great tit chicks hatch and are fed on them. Survivors float down the tree on a silken thread, either to another tree or to pupate underground before the cycle begins anew.
A few days later, returning home again after dark, there on my front door, as if waiting for me, was a male winter moth. Small, dusky brown with faint wing bars, it looked entirely unremarkable. As I watched him fly away, pheromone finding, I felt the warm glow of knowing a few of its secrets.