IT may be a start stop summer as far as sunny weather is concerned, but a heatwave is persisting in a small pocket of the Connemara Gaeltacht. Temperatures are topping 32 Celsius, there's a sapping 85 per cent humidity and the feel is definitely tropical.

A special meteorological blessing is not being bestowed on Irish speakers, but the area is benefiting from one of the most unusual tourism amenities in the west of Ireland - the Tropical Butterfly Centre in Casla has been such a success that within a year of opening, its developers are adding an exhibition centre.

The centre is the brainchild of the Rehab Group, and doubles up as an all weather amenity and training centre where 10 trainees study horticulture, hothouse plant production - and how to deal with tourists who come to see its exotic butterflies.

In a simulated tropical environment (a large, airy enclosure with constantly watered paths which leech minerals for the butterflies to feed on), there are up to 40 species - about 600 butterflies in total - among a splendid mass of tropical plants.

Pupae (between the larval and adult stage) are flown in overnight by courier from Britain, where they are bred, though they originate from Malaya and South American rain forests. They are nurtured in a hatchery before being introduced to the enclosure among the plants and tropical birds which keep them company. While there are four butterfly centres in Ireland, Casla already claims to have the largest display of living butterflies and, uniquely, provides Irish language tours.

The pupae look like crumpled leaves or green pea pods. It is hard to believe that within days they emerge - after hectic feeding - to become such beautiful aerial beings. While hundreds of butterflies succeed in hiding among the tropical plants and exotic flowers, during a good fly period up to 100 can be seen.

The Owl butterfly - the largest in the collection with a wingspan of six inches - is a favourite. It may be the biggest, but it's difficult to locate. It sits around for hours doing next to nothing and then does a couple of mad flights around the house" and then roosts-up for the rest of the day. As its name suggests, it is most active in low light.

Looking after butterflies is a captivating business. Each one has its own quirks. The Tree Nymph is fussy. It needs a specific plant for its eggs and literally bursts if that plant is not available.

The butterflies feed on rotten fruit, honey, water and nectar. Insect control is paramount, so the parasitic wasp is introduced to suppress the white fly - it's not like the Irish wasp and can be barely seen - while trainees learn about organic control of insects, as blasting them with insecticide would ensure elimination of the butterflies.

The centre manager, Richard Casburn, says that since the centre opened in mid 1995 he is delighted with tourist numbers. Casla remains open to the public until the end of September. The display is then scaled down; fewer, butterflies are introduced and some simply hibernate.

"It is well supported from a casual tourism point of view," says Richard Casburn. "We expect it to do extremely well. The special features in the centre have enhanced the ability of trainees. Getting them to do tours has led to tremendous integration between them and the public."

The new phase, built with the help of Udaras na Gaeltachta, will enable more trainees to work there, and includes audio visual facilities and new display areas for live insects, spiders and toads likely to thrive in the Casla tropics.

Training instructor Sean Purtill has no doubt that the facility is proving to be of special benefit to people working there. "They develop an appreciation of the natural world," he explains. "It's a mini ecosystem here. They are interacting with people from all over the world. They are learning tourism and people related work. It's all very beneficial."

For the Aztecs and for the African Lulua tribe, the butterfly symbolised the soul. Visiting the butterflies of Casla, it is easy to grasp the good feeling they engender. The place is an abundance of colour amid the alluring sounds of cockateels, canaries, love birds and budgerigars.