They're the best loved creatures in the insect world. Now you can get up close to some of the world's most stunning butterflies here in Bristol, as David Clensy discovers

When you think of Bristol Zoo Gardens, your mind may immediately turn to thoughts of roaring lions, playful penguins or melancholy gorillas.

But a new exhibit is turning visitors' attention to the fascinating, short lives of much more delicate creatures.

There's a sense of magic from the moment you enter the zoo's new Butterfly Forest.

“It's a bit like stepping through the wardrobe into Narnia,” says curator of invertebrates Warren Spencer as he pushes through the three sets of chain curtains designed to keep the free-flying butterflies from escaping.

“This area is also deliberately kept dark, because butterflies don't like flying into the darkness.”

As he moves the final curtain aside he unveils a vision of Eden.

Tropical plants and trees are growing throughout the exhibit, and hundreds of over-sized butterflies flutter through the air like a shimmering rainbow. Each child that enters the sophisticated polytunnel, gives the same reaction – a wide-eyed gasp. Here, at last, is a fairytale world they can believe in.

“We have 200 to 300 butterflies in here at any one time,” Warren says.

“It's impossible to keep track of exact numbers because butterflies are so short-lived, though they're not as short-lived as people often think – it's a complete misnomer that they only live as butterflies for a single day.

“Most survive in their butterfly form for three to four weeks, although some can live up to 12 weeks.

“Moths are another matter – sometimes they only tend to live for a few days, because many moths effectively don't have mouths. They're not designed to be around long enough to eat anything.

“They only live long enough to mate and lay eggs to start another generation of caterpillars.

“It's a little bit more cheerful if you're a butterfly – you do, at least, have the ability to feed on nectar.”

The exhibit has been set out with a variety of plants that are either suitable for butterfly feeding or egg-laying.

“The idea is that the exhibit will continue to develop over the next few years,” Warren says. “This really is just the start of the project.

“Eventually the plants should grow up and cover the ceiling – so it really will be like walking into a jungle. When we get to that stage some of the butterfly species in here may even be able to propagate themselves, generation after generation, with very little influence from the staff.”

For the moment though, all the butterflies arrive at the zoo in their pupae stage.

“We buy the pupae from special sustainable butterfly farms in Costa Rica and Kenya.

“We've chosen the farms very carefully, because they're set up in such a way that they offer a fair industry to the local people, and they also work in a sustainable way – none of the butterflies are lifted from the wild. Some of the money we pay for the pupae also goes into a series of conservation projects in these countries, to help those species of butterflies that are endangered in the wild. It's a wonderful system, which ensures that the local people and butterflies benefit.

“It's nice to be able to help butterflies around the world – Bristol Zoo already supports work to protect and monitor the silky wave moth in Bristol's own Avon Gorge – its only English habitat – through the Avon Gorge and Downs Wildlife Project.”

There are between 15 and 25 different species in the exhibit at any one time, ranging from the stunningly beautiful Blue Morpho to the enormous Brown Owl butterflies.

But they all start their life as a butterfly in a special climate- controlled cabinet at the back of the exhibit.

“We call it the chrysalarium,” Warren says. “It's designed so visitors can watch each butterfly emerging out of its chrysalis.

“It's an amazing thing to see. You'd never believe that creatures as big as these could be developing in such small pupae.

“When they first come out, their enormous wings are folded around themselves. They open these out, and hang next to their chrysalis, waiting for their wings to dry out before they can fly for the first time.

“It all depends on temperatures and conditions, but most butterflies will spend about five to 15 days in the pupae.

“Before this they have already been living, for many weeks, as caterpillars – feeding constantly to prepare for this incredible metamorphosis.”

The temperature in the attraction is kept to a humid 30ºC.

“It's the first exhibit of this kind to use a sustainable furnace to create the heat. We feed it constantly with special recycled wood-chip pellets.

“It means we're not having to use gas or electricity to run the furnace – and therefore burning more fossil fuels. Climate change is something we should be particularly aware of,” he explains. “Butterflies tend to be the first to suffer, because they're so intrinsically linked to their habitats.

“Any changes in plant life have immediate knock-on effects for butterflies.

“Even in our own country, butterflies are having a difficult time.

“There are fewer native butterflies than ever before. There are lots of reasons why that's happening, including ever-changing farming techniques, but I personally believe that climate change is also playing a part.”

In order to help the native English butterflies, a new nectar garden has been built to surround the polytunnel.

“We've included all those nectar-rich plants that butterflies particularly love,” he says.

“Our dream is that when the plants are nicely matured, the public will see hundreds of butterflies flying wild as they make their way towards the polytunnel.”

Warren hopes that visitors to the attraction will be inspired to do their bit to help wild butterflies.

“It's going to be a place where people can learn a lot about these wonderful creatures,” he says. “Their behaviour is fascinating to watch. Each of the species acts in a different way, and sometimes they can be quite eccentric.

“Take the owl butterflies, for example. As part of their mating rituals, they will sometimes fly in a neat snake of up to 12 individuals. It's a remarkable sight.”

Another highlight of the exhibit is the enormous Atlas Moth.

“It's the largest moth in the world – as big as my hand,” Warren says. “We wanted to have it here so that people really do get an idea of the variety in the butterfly and moth world.

“They really are creatures that you could study for years and still make new discoveries all the time.

“I hope visitors to the Butterfly Forest will feel just as inspired as I do about this new facility. It's a magical way to be introduced to the butterflies' world.”

● Admission to Bristol Zoo Gardens, including a voluntary donation to the zoo's conservation work, is £12 for adults, £7.50 for children, and under threes go free. For more information, visit www.bristolzoo.org.uk