Garden blogs

Volunteer makes priceless contribution to Plas Pilipala

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With the preparation for the National Botanic Garden of Wales’ first ever butterfly attraction – Plas Pilipala, opening to the public on the 1st of July 2016 – it’s all hands on deck as our staff and volunteers prepare for the arrival of our first batch of butterfly pupae.

As I write, our horticulture team are busy filling in what used to be the Tropical House’s pond and stocking it with delicious nectar plants for the butterflies. Meanwhile, nets are going up to prevent the butterflies dying awful deaths in the fans at the top of the Tropical House and our butterfly keepers are busy planning the daily schedule in the butterfly house and learning to identify our 23 different butterfly species.

But one of the most important jobs of all, and one without which our butterflies would never see the light of day, has been laid on the shoulders of beekeeper and Garden volunteer, Julian Caruana.

Julian’s job – to design and build the emergence cage for our pupae – is no small undertaking. This essential piece of kit is basically an incubator for our baby butterflies, and just like regular babies, these pupae require the perfect conditions to survive and develop. Tropical pupae require a humidity of 80% in order to emerge, and will become stressed, even twitching and jerking if it drops too low. They also require a temperature of 27-28 ᵒC. If the temperature is just a few degrees out, it could lead to the adult butterflies failing to emerge from the pupa casing at all. The cage also needs to be big enough to fit four hundred pupae, suspended with glue from wooden rods, where the adult butterflies can emerge, dry out their wings and prepare for life on the wing.

Julian’s connection with the Garden is as one of our volunteer beekeepers, who look after the Garden’s colonies of bees which are used for research and pollination purposes. His woodwork skills are generally called upon for beehive building and maintenance, but he has taken on a big responsibility in volunteering to build our emergence cage.

A few meetings back in March led to a rough plan of its size and shape, which were inspired by photos of similar cages from other butterfly houses. After we’d worked out the dimensions we needed (by measuring our arms and hands to see how far into the cage we’d be able to reach!), Julian drew a rough scale drawing and then really got to work.

The first step was to make the skeletal frame of the cage, as shown in the first picture. From this skeleton emerged a very professional-looking emergence cage, clad in wooden slats, made from a special Thermowood which maintains a constant water content in humid conditions in order to prevent rot and wood ‘movement’. Then came rows of slats in which the rods of pupae would rest, a slanted, stainless steel clad roof to keep water off the cage, a thermostat-controlled heater to monitor and regulate the temperature in the cage and the final piece of the jigsaw, a pair of toughened-glass doors. Today, the cage comes to its new home in Plas Pilipala, ready just in time for the first few pupae.

When you visit Plas Pilipala, by all means, enjoy the butterflies – that’s what they’re there for. But if you can spare a moment, use it to consider the amount of research, planning and hard work that has gone into its development, not least by volunteers like Julian who make a priceless contribution to everything the Garden does.