Another Life:As butterflies go, the small skipper is not exactly glamorous: a casual glance could mistake it for a little day-flying moth. But in summer sunshine, its darting, expert flight and golden-brown glint does catch the eye, along with its way of perching, wings half-open, as if eager to take off again, writes Michael Viney.
So it must have been quite an uplifting sight, on a rare dry and sunny day late last month, when a whole colony of small skippers were on the wing along a wild, grassy ride beneath an ESB line in south Co Wexford, and seven butterfly enthusiasts were trying to count them. They eventually agreed on 141, plus another 17 from a spot half a mile away, and went away ecstatic. The small skipper, Thymelicus sylvestris, hitherto a very English butterfly, seems to have arrived in Ireland to stay.
The first sightings came a year ago, thanks to an uncommonly nature-wise farmer (with, presumably, a good butterfly book). Jimmy Goodwin reported his find to Chris Wilson, the ecologist who looks after the Wexford Wildfowl Reserve, and a subsequent digital photograph brought him post-haste through the county's leafy lanes. By September, with identification confirmed, some 30 butterflies had been counted. But could this be an accidental introduction and a purely temporary colony? Or had global warming given Ireland its 29th resident butterfly?
The small skipper lays its eggs in the leaf-sheaths of Yorkshire fog, the tall, velvety grass with feathery pink panicles of flowers. The larvae hatch and hibernate, pupating in late spring in loosely-spun tents of leaves near the base of the plants. Adult butterflies emerge, more or less together, in July, though individual stragglers may be seen up to mid-September.
Common enough in England and Wales, small skippers are certainly moving north - last year also saw the first colonies at the Scottish Borders. The species is normally quite sedentary: a study in southern England showed that two-thirds of the population moved less than 20 metres per day - so the spread is clear evidence of climate change.
Even so, how did the butterflies get to Co Wexford? If they were carried on easterly winds, why haven't they colonised Ireland before? There's always a chance, for example, that their larvae arrived in hay brought in with horses from England. But warming is undoubtedly the key to their survival and expansion. Co Wexford is already the bridgehead of colonisation by the magnificent emperor dragonfly and its potential for fresh migrants is not lost on the Wexford Naturalists' Field Club (with so much excitement, its membership should boom).
So much for the kinds of insect that have, as it were, a ready and observant fan club. But climate change is bound to bring us insects we might not wish to have (hornets, for example) and those which could do us economic harm. Some of the latter were highlighted in a lecture by Dr Roy Anderson, of Queen's University, Belfast. He manages the Hillsborough, Co Down centre of the UK's Environmental Change Network and is ever alert to new bugs on the block, particularly those to do with trees.
Ireland is already accommodating a good many naturalised aliens brought in with plants from Australia and New Zealand, most of them harmless and even beneficial consumers of forest litter. With extra warmth and thriving garden centres, Dr Anderson foresees "a continuous and increasing accumulation of non-pestiferous but invasive alien invertebrates in Irish forests with unknown consequences".
The biggest-known threats are to our conifer forestry. Two new pine weevils have already arrived in the north-west, and climate change, warns Dr Anderson, will probably increase the populations of Hylobius abietis, the large and troublesome weevil that attacks clearfell replanted with young conifers.
Waiting in the wings is the great spruce bark beetle, Dendroctonus micans, first detected in Britain 25 years ago and already as far as Anglesea in Wales, and the aggressive European spruce bark beetle, Ips typographus, for which there's no control except clearfell. Both are capable of killing Sitka spruce already stressed by climate change.
Potential pests of hardwood trees are far fewer, unless the dreaded Asian longhorn beetle, Anoplophora glabripennis, moves up from southern Europe.
August is often the month in which a reader becomes alarmed by the approach of a large insect, boldly striped in yellow and black and with a long spike at the rear. This is the hornet-like but totally harmless female wood-wasp, Urocerus gigas. The spike is a stout, saw-toothed ovipositor, used to drill holes in conifer wood to lay eggs.
The insect's larvae tunnel even deeper into the wood and may spend up to three years slowly chewing away. They bring their burrows back eventually to within half-an-inch of the surface, so that the mature wood-wasp has not far to emerge.
EyeOnNature
I've noticed a mangy-looking fox with fur gone from her back and tail. It doesn't seem bothered, and there are no signs of scratching or wounds.
Peter McIlwaine, Manor Kilbride, Co Wicklow
I don't think it has mange. Foxes moult in summer from the legs, tail, rump and progressively forward on the body, and the fur is not fully replaced until November.
I spotted a dark, weasel-like creature loping across my driveway. It was about 30cm long. Was this a mink?
David Wilcoxson, Tinahely, Co Wicklow
It could have been a young mink. An adult mink measures 50-60cm.
There were three swallows' nests on the centre beam of the barn, a pair nesting in each of the two end nests. When these broods were fledged, one of the pairs started a brood in the centre nest and a battle between the two pairs ensued, resulting in the fledglings from this last brood being killed.
John McClung, Kells, Co Antrim
Swallows will defend a territory ranging from four to eight square metres.