Moth magic

We’ve all seen those items on the local news where a rescued animal, a seal perhaps or a badger, is finally released into the wild: the mixed feelings of its carers – pride, anxiety, regret – like a parent with a first-day-at-school infant. Well, such feelings – on a more modest scale – were shared with me recently by Anne, a fellow Wharfedale naturalist, their object – a moth!

The story starts in early June two years ago when a female puss moth was caught in the Burley trap. Puss moths are attractive creatures – creamy white wings, spotted with black, and luxuriant white fur all over the body and legs, hence, I guess, the name. The female, sleepy in the morning sunlight, was placed on a log and put in a box in a shaded spot, ready to be photographed later in the day. When Anne came to take the photographs, she discovered that the moth had laid several chestnut-coloured bead-like eggs on the bark. The photo was taken, the moth released and the eggs put on one side to await events.

Actually, events proceeded rapidly: eight days later the eggs hatched – 2mm. long caterpillars emerged, their bedraggled black fur making them look like extremely skinny kittens. These were divided between a number of naturalist friends and Anne took two. Caterpillars are simple organisms, designed to eat and grow. On a diet of fresh willow leaves these two were revealed as champions on both counts. They munched, grew and kept casting their skin to accommodate increasing girth till they were about 7cm. long, smooth and green with a natty row of yellow spots on each flank – a credit to a nutritious diet and safe environment. On 20th July they began to change colour – flushing a dark red, like ripening plums; on the 21st each began the laborious process of constructing a cocoon, spinning silk for the structure and filling this in with chewed bark. The process took about three hours, at the end of which each caterpillar was encased in a domed shell that hardened and darkened to exactly match the bark on which it stood, so that all one saw was a sort of fault or knot in the natural texture of the bark.

Inside this papier mache home the most miraculous transformation takes place. The simple sack-like caterpillar body breaks down and from these parts is constructed the complex, exquisitely beautiful adult moth. According to the reference books the puss moth over-winters as a chrysalis, emerging in May- June the following year. That’s the theory. So, the box was put in a safe place, dampened tissue changed regularly to keep the precious contents from drying out, and patience was cultivated. May 2007 came and went and nothing happened. Summer passed – still nothing. So much for theory. Then last month, two years later, a tiny hole appeared in one of the domes and a small crumpled moth fought its way free. Soon it was busy gradually extending its abdomen with regular contractions; then it was the turn of the wings: these tiny frills attached to the shoulders soon began to lengthen and smooth out and suddenly flipped over into the characteristic moth-at-rest position. Now all it had to do was harden the tender surfaces, rest and wait for darkness – a beautiful male puss moth. Its sibling emerged a day later, another male, and both were released into the garden where, we hope, their delicate feathered antennae picked up that vital trail of pheromones which would lead them to mates and the beginning of another cycle of life.

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