Another Life: Captivating moth on the rise ignores the hovering humans

An oldie’s sortie to the loo at three in the morning confirmed the progress of summer, as a heart-stopping clatter about my head resolved into a big brown moth making bouncy overtures to the ceiling light. There have been times when, agog at the infinite variety of noctuids, I would have stowed it somewhere dark until morning, for matching among the many pages of possible species. It might have been an Old Lady, say, though not really big enough, or a Dark Arches, or a Great Brocade. As it was, this not being my first trip of the night, I caught it in cupped hands and tossed it gently back out the window.

The mystery and beauty of moths is, however, clearly catching on, as more than 900 sightings were reported last month to mothsireland.com, our leading lepidopteran website. Many arrived from enthusiasts using overnight light traps. And to me came a phone call from a reader in the Mayo interior, Stephen Clancy of Balla, who found a hummingbird hawkmoth whirring away at pink campion flowers in his garden.

At the first encounter with the day-flying Macroglossum stellatum, especially in Ireland, anyone has to wonder at its novelty and elegance. Here is a browny blur hovering in front of a flower while its long, thin tongue probes its heart for nectar. At rest, it resolves into a stubby moth about four centimetres long, with very dark and narrow front wings covering a pair of amber ones, and a fan of dark hairs at the tail. It does, indeed, hum a bit, quite audibly, as it darts from flower to flower, paying little or no attention to any hovering human.

There has been a marked rise in Irish reports of it since 1980, and while at least a few are now seen every year, especially in the east and south, there were influxes in 2000 and 2003 when readers expressed their puzzlement, awe and fascination – even, on occasion, tremors of fear and disbelief at something so new and strange.

The moth is most often noticed over the next few weeks of summer, but readers’ sightings have come as early as March 25th – this from Blackrock, Co Dublin, in 2012. This suggested the possibility of overwintering of this southern European species as the climate warms, but the experts want harder evidence. The moth was taking nectar from a starry white floret of viburnum, in line with the moth’s known preference for two very different shapes of flower – those with long tubes, such as honeysuckle, tobacco plants or petunias, and those with clusters of small, round, symmetrical flowers. Notable among these is dame’s rocket, a clove- scented wildflower of the moth’s native Spain and a prolifically self-sowing plant in my garden – the scene, indeed, of my only meeting with the moth some years ago.

Bronze caterpillar

Macroglossum stellatum

now ranks as the commonest of visiting hawkmoths, but there are others with spectacular, art nouveau shapes and colours – the poplar, death’s head, lime, convolvulus – that people are eager to capture with digital cameras and phones. Our lovely, pink-splashed native hawkmoth, the elephant, on the other hand, is more often reported in the form of its big bronze caterpillar, usually found chewing on the leaves of fuchsia and sometimes inflating an alarmingly painted “eye”.

The hummingbird hawkmoth is not the only moth to be confused with another kind of creature. A reader near Westport, Meriel Donaghy, was recently stacking willow logs brought from her parents' garden in Donegal when she found a what looked like a giant wasp, moving sluggishly and freshly emerged from a nearby pupa. Looking up "hornet" in Google's images, she came across pictures to match her insect – not, in fact, a hornet, but the lunar hornet moth, Sesia bembeciformis. This is the largest of Ireland's day-flying clearwing moths – a species that mimics the warning colours of a wasp but lacks its pinched-in waist.

S bembeciformis gets special mention in the 2006 Butterflies and Moths of Northern Ireland, by Brian Nelson and Robert Thompson, one of the mammoth natural history volumes published by the Ulster Museum. The moth used to be much more common in the north's old willows and apple trees in damp places. The larvae burrow into the tree and stay there for two winters, the pupae emerging to yield the adults in late June or July. Their wings then lose most of their scales, leaving clear "windows" between the veins. They then fly away in the sun – as Ms Donaghy's did.

Only a few adult moths have been seen in today’s Northern Ireland and the Westport encounter may rank as a rare modern record for the Republic. Our reader would welcome a colonisation of the willows already grown from Donegal twigs. But hornet clearwings like their trees old and mossy and holed by many generations of their kind.