The shift in perspective had something to do with it. I’d been crouched low, scratching weeds from some paving, when what appeared to be a small Chinese dragon rippled into view. Startled, I rocked back on my heels. The dragon seemed covered with hairs, which felt alarming. Then I got my bearings and recognised it as the caterpillar of a tussock moth, the vapourer to be precise, a creature that if it weren’t so common would be one more example of how nature can outperform the human imagination.
A little less than an inch and a half long, the vapourer’s black body was fringed with hairs the colour of ripe wheat. These emerged from raised scarlet pads called tubercules, one either side and two on top of each segment, except for the four middle segments, which were crowned with dramatic tussocks more yellow in tone. Aware of my presence, the caterpillar flexed itself. Vapourers have defence glands on the tail and, when threatened, flex like this to empty noxious fluid on to their body – a defence against predators, but no threat to a human.
Vapourer moths are unusual in several ways. The males fly during the day, especially in the late afternoon, on the hunt for the female’s pheromones drifting up from her hiding place, whereby this moth acquires its name. Female adults are flightless, remaining close to the remains of their pupae, where they spend the rest of their short lives incubating huge numbers of eggs. They are bigger than the males, and that extends to the caterpillar. Judging by the size of mine, it was female. Neither female nor male will eat after pupation; they last only as long as the energy they managed to consume as caterpillars.
Another quirk is their habit of dispersing after emerging from the egg – unusual behaviour for moth caterpillars. That doesn’t mean they won’t congregate. London was once famous for its vapourer infestations. As Yorkshire’s climate warms, northern vapourers, formerly restricted by cooler temperatures, may in the future behave more like their nesh cousins in the south.
• Country diary is on Twitter at @gdncountrydiary
• Under the Changing Skies: The Best of the Guardian’s Country Diary, 2018-2024 (Guardian Faber) is published on 26 September; pre-order now at the guardianbookshop.com and get a 20% discount
