Butterfly Journey

In November 2008 the Zoo opened its latest exhibit the Butterfly Journey, which is the largest zoo-based butterfly house in the UK. The 400sq metre tropical house which is heated to 28 degrees Celsius, is home to more than 30 species of butterfly from South America, Africa and south east Asia. The exotic species on show will include Blue Morphos, Giant Owls, Glasswings, Swallowtails and the Atlas Moth.

Our keepers Adam Richardson and Heather Prince are experts in the field of butterflies and have outlined below in their 'Keeper's Notes' exactly what they do on a day to day basis to look after the butterflies and to make the exhibit such a spectacular experience.

" From a keeper’s perspective, we can certainly think of worse places to spend the day but it was no easy task achieving and now maintaining this slice of tropical paradise.

The final few months prior to the opening day were spent ensuring that all the needs of the butterflies were going to be met. First and foremost this meant planting the hundreds of exotic plants, all of which were carefully chosen for specific reasons. For example Lantana, a tropical evergreen shrub which produces many flowers over the majority of the year, was chosen as an essential nectar source to feed the butterflies. Other plants were chosen due to them being the host-plant (larval food) of a particular species or family of butterflies, for example the banana, citrus and passionflower plants serve as a host to the eggs and larvae of the giant owl (Caligo memnon), swallowtails (Papilio spp.) and the longwings (Heliconius spp) respectively. Those plant species not serving as a nectar source or a host-plant, were chosen for their aesthetic value - to better the visitor experience of being immersed in tropical vegetation.

In amongst the plants, artificial flowers can be found with tubes in the centre that hold a sugar and water solution. These act as a substitute for nectar during times of the year when there are fewer natural flowers for the butterflies. We have chosen to trial the use of these modified artificial flowers, rather than using the normal plastic discs with painted-on flowers that most other butterfly houses use, as we hope they will fit in better with the natural theming of the exhibit.

Along with all the plants, a seemingly endless amount of rocks and pebbles had to be carried into the house. These were then individually placed to make up the bed of the stream which meanders from the waterfall down the length of the house to the entrance. It was a long and tiring task but an important one as the watercourse helps to achieve that vital environmental condition – humidity.

Another of the essential conditions is heat. It’s not always comfortable for us keepers working in temperatures in the high-twenties (80 degrees Farenheit) but without the heat there would be little if any flight activity for our visitors to enjoy. Visitors often tell us we have the best job on a cold winter's day but sweeping, digging and other necessary manual work in the Butterfly Journey ‘tropics’ can be an uncomfortable labour of love at times.

Now that the exhibit is up and running the challenge is to keep the butterfly population healthy and prosperous. We have strict daily duties that we carry out in order to achieve this. The mornings, before we open the doors to the public, are always the busiest time for us. The waterfall does help maintain humidity but spraying over the foliage and watering the paths and soil raises it to around the necessary 70%, so that’s generally the first of the day’s tasks.

Inevitably, with any animal population where the adult stage only lives for two to three weeks, there are always going to be deceased butterflies to collect but this is offset by the next job - releasing the newly emerged butterflies from the emerging case. Unfortunately for our visitors, the vast majority of the butterflies emerge during the early hours. This means you are more likely to see the adults finishing drying off their wings whilst hanging from the tree adjacent to the case, rather than the marvel of a butterfly pulling its swollen abdomen out of its pupa and pumping up its wings. Of course, not every butterfly emerges successfully from its pupa. Each morning and afternoon we check through the pupae looking for the early signs of parasitism or disease whether it be viral, fungal or bacterial. It is extremely important for us to remove any bad pupa as disease can spread quickly in the warm humid conditions of the house.

One of the most common questions we are asked is in reference to the breeding of the butterflies. Even though we are successfully rearing larvae of a few chosen species, we cannot possibly be completely self-sufficient when it comes to stocking the exhibit. The majority of the pupae that can be seen in the emerging case are those which we have obtained from sustainable butterfly farms in the tropics. When it comes to choosing which species to order, out of several hundred possibilities, it’s a carefully-calculated decision. Our choices are based on factors including differing times of activity, specific behaviour or educational benefits, and we’d be lying if we said some of it wasn’t down to personal preference.

We receive our pupae delivery once a week, usually on a Wednesday. The pupae are sent to us carefully laid among layers of cotton wool in a polystyrene box, the presentation somewhat resembling a box of chocolates! We then have to pick them out and either carefully pin them by their silk (naturally spun by the larvae in order to attach themselves to a leaf or other object before pupating) or glue them to a doweling stick if the silk is absent. These sticks are then placed in the emerging case where they are kept at a constant temperature and humidity. Our mid-week visitors may see us preparing the pupae if they look through the windows into the butterfly breeding room near the exit. This is also the room where you are more likely to see the larvae which have been bred here at the zoo. Within this room the delicate caterpillars have more protection from over-eager fingers until they pupate, after which we move them into the emerging case.

You may also see our silk moths in this room, or on one of the plants by the window, or at rest in the emerging case. Despite popular belief, it is actually only the silkmoths which emerge from a cocoon. These protective cases can be seen hanging with the rest of the pupae.

The rest of our days are taken up tending to the plants, ensuring that rotting fruit is available to those species which desire it, keeping strict records on emergence and disease, and just staying hydrated in the tropical conditions! At least one of us is always available within the house to answer any questions that our visitors may have, so don’t hesitate to ask. We hope to see you soon!"

Photographs courtesy of Richard Gibson.