Nature
All of a
flutter
Ireland’s butterfly species may be few in number, but they are an enduring harbinger of summer and source of constant surprise, says Eugenie Regan. Photos by Chris Wilson
B
utterflies are fascinating creatures. Not only as the classic biology lesson for small children of the caterpillar turning into a butterfly, but also as intriguing creatures that attract our attention as a flash of colour while on a country walk. Butterflies are amongst the most charismatic of our fauna. They are beautiful emblematic animals that enrich our quality of life. They fulfil a vital role as flagship species; engaging the public, local communities, and the media in wildlife conservation. Butterflies belong to the order of insects known as Lepidoptera, meaning ‘scale wing’, and it is the overlapping formation of these pigmented and reflective scales that give butterflies and moths their wonderful variety of colours. We have 34 different species of butterflies in Ireland. This compares with 58 in Britain and over 440 on the continent. While Ireland may not be a hotspot for butterflies, we know very little about ours and interestingly the same species can behave very differently in other countries. We also have had a few scientific surprises recently that have puzzled scientists and caused jealousy in Britain! I will explain…
The Peacock butterfly
The mystery of the Wood White Butterfly experts had been puzzled by the behaviour of some of Ireland’s butterflies for over a century. The Wood White butterfly is a small, unassuming insect that rarely attracts much attention. In England, it is a very rare butterfly which is under threat of extinction. In Ireland, it occurs across the country and behaves quite differently. While Wood White butterflies in England are restricted to woodlands, Wood Whites in Ireland are much less choosy about where they live and can be found living along roadsides, fields, and laneways. English lepidopterists (a fancy word for butterfly nerds) assumed it was something to do with the fact that us Irish puzzle them at the best of times! We are wayward, much too easy-going, and very lenient with rules and regulations. And the Wood White appeared to be the same. Two Irish lepidopterists, however, were not convinced. They undertook a detailed study of the Irish Wood Whites and discovered that we have a different species from the English Wood White! And we now have a butterfly in Ireland that doesn’t occur in Britain and we have made the British lepidopterists very envious indeed.
The Réal’s Wood White doesn’t occur in Britain - much to the envy of British naturalists!
The Painted Lady
The Painted Lady migration of 2009 was a spectacular one. These tiny creatures have wing spans of less than 3 inches and yet travelled My favourite butterfly at the moment is without doubt the Painted from the Atlas Mountains of Morocco to Ireland to escape the hot Lady. It may not be the most beautiful butterfly but it is one of the summer. Heavy winter rains created ideal conditions for the food most fascinating. Weighing less than a gram these butterflies can plant of the caterpillars in Africa and combined with ideal weather for migrate hundreds and sometimes thousands of miles. However, travelling north over the May bank holiday weekend, Ireland despite being the most common species in the world its migration is a experienced one of the largest migrations on record. mystery to scientists. The Painted Lady is a migrant butterfly and it provides some of the In 2009 I was looking out my kitchen window and saw a butterfly most impressive and memorable butterfly spectacles in Ireland, fly by. Not unusual. But then another and another. I went outside to arriving in great abundance in some years while remaining scarce in see what they were and they were all Painted Lady butterflies. others. Once arrived (generally in early summer) the butterfly breeds on thistles during the summer months but is not capable of “Painted Ladies migrate from the Atlas surviving our winters. In fact, the species is believed to be biologically Mountains of Morocco to Ireland to incapable of proper hibernation and escape the hot summer.” thus the adults have a nomadic lifestyle, moving from country to country. What happens to these butterflies at the end of the summer has been an enduring entomological mystery. They cannot survive here due to the cold so it seems logical that they should migrate south to warmer climes. Such return migration is regularly recorded elsewhere in Europe but there is almost no evidence that they do so from Ireland. This is all the more odd as the closely related Red Admiral is often seen flying southwards in the autumn. Scientists speculate that the Painted Ladies undertake southerly migration at night or at high altitude. But for the moment, the mystery remains. The Painted Lady travels hundreds of miles each year from northern Africa
Nature Getting hot… Butterflies are becoming key to understanding the effects of climate change on our wildlife. Butterflies are very sensitive to changes in temperature especially in the chrysalis stage so they are inexorably linked with climate. Put simply, climate limits where butterflies can live more than the availability of habitats or the particular plants on which they feed. So species can spread into new areas if the climate becomes warmer. They can also produce multiple generations within a year as a result of warmer summers. Both of these effects are being seen in the Irish butterfly population. Firstly, we have new species arriving to our shores. The most recent is the Essex Skipper. This butterfly has more than doubled its population in Britain in the past 20 years and was first discovered in Ireland in county Wexford in 2006. Since its discovery, it has been found in other sites in Wexford and no doubt will become a common member of the Irish butterfly fauna in the coming years. A warmer climate also impacts on the behaviour of butterflies. Increased temperatures allow them to produce multiple generations within the one year. This has been recorded with the Holly Blue butterfly in Ireland in recent years. This butterfly only produced one generation per year. This changed to two generations in the southeast of the country and each year this change spread northwards. The Holly Blue butterflies now achieve a second generation as far north as Belfast. It’s amazing what an impact a small change in temperature can make.
The Gatekeeper is expanding its range as a result of climate change
Under threat of extinction The decline of Ireland’s butterflies throughout the last century has been dramatic and a cause for great concern, not only to naturalists but also to many people who can still remember the pleasure of seeing wildflower meadows dancing with butterflies. A recent report from the National Parks and Wildlife Service has found that six of our butterflies are under threat of extinction in Ireland– Pearl-Bordered Fritillary, Small Blue, Wall, Dark Green Fritillary, Large Heath and Marsh Fritillary. These butterflies have declined for a number of reasons but habitat change and destruction are the main culprits. Modern agriculture has had a huge impact on our wildlife with monocultures of deep green ryegrass swards dominating our landscape. This has resulted in the loss of wildflowers and nectar resources for adult butterflies and fine grasses that many of our native species feed on as caterpillars.
Keeping a close eye on our butterflies Two new initiatives have started recently in Ireland in response to this concern for dwindling butterfly populations. The first is the Irish Butterfly Monitoring Scheme that is co-ordinated by the National Biodiversity Data Centre. Over 150 volunteers across the country monitor butterflies in their local area each week and report their results to the Centre. The scheme began in 2007 and has been a great success. Last year we had huge media interest in the Scheme and it seemed that every radio station wanted an interview and every paper had butterflies brightening up their pages. Why the sudden interest? Why the huge response to our call for new volunteers? It took us completely by surprise. On the one hand, we are now run off our feet with this project. Running to stand still or perhaps all of a flutter... The second initiative is the establishment of Butterfly Conservation Ireland. A tiny charity whose aim is the conservation of Irish butterflies, moths and their habitats. They run a programme of events throughout the summer and operate a nature reserve at Lullybeg, county Kildare. For further information see www.butterflyconservation.ie
The Ringlet butterfly
If you’re interested in butterflies… If you’re interested in wildlife, butterflies are a great group to get started with. We have a manageable number of species that are easy to identify, they only come out in nice weather, and you can make a valuable contribution to our understanding of these animals. A simple record of when and where you saw a species can be important information on the distribution of our butterflies and their flight periods. A note on the behaviour and what food plant it was on can contribute important information on the ecology of the butterfly. For online resources
on Irish butterflies see www.irishbutterflies. com and www.butterflies.biodiversityireland. ie. A handy one-page identification chart is available from the Dublin Naturalists’ Field Club and the Irish Peatland Conservation Council. Also butterfly net can be helpful but is not essential. If you do collect records of Irish butterflies, then the National Biodiversity Data Centre would be delighted to receive them – go to www. biodiversityireland.ie. From the response last year to the Irish Butterfly Monitoring Scheme, it appears that there is a real shift in interest in wildlife again. It’s as if this recession has led us back to our landscape. Out of the shops and into
the fields. Brought us back home in a way. With over 12,000 species of insects in Ireland, monitoring butterflies is just one small step to gaining a better understanding of our insect fauna. But it’s certainly one large step for ourselves in gaining a better understanding of the natural world around us. So my challenge for you this year is to take time to observe the wildlife on your walks and in particular the butterflies. Note how nature is finely linked with the seasons and climate. A final word: in 1928 a net-wielding Englishman was arrested in county Galway as being obviously an escaped lunatic. Let that not be a discouragement to his successors!
The Small Tortoiseshell
Top butterfly walks in Ireland: Leinster
The Raven National Nature Reserve, Co. Wexford Scragh Bog, Co. Westmeath
Connacht
Mullaghmore, Co. Sligo Shores of Lough Carra, Co. Mayo
Munster
The Burren National Park, Co. Clare Dromore wood, Co. Clare Killarney National Park (Muckross Peninsula), Co. Kerry
Ulster
Murlough National Nature Reserve, Co. Down Ards Forest Park, Co. Donegal
Dr Eugenie Regan is an ecologist with the National Biodiversity Data Centre and co-ordinates the Irish Butterfly Monitoring Scheme.