The Winter Garden is part of the big office-conference complex located next to the entrance of Zoo Antwerpen and along one side of the Queen Astrid Square (Koningin-Astridplein), the square next to the Central Station where the Zoo's entrance is located.
The complex was designed by architect Emile Thielens and built between 1895 and 1897 and most recently restored between 2013 and 2016. To my knowledge no structural work was done to the Winter Garden during this restoration.
Somewhere between 2000 and 2013 for a while some animals (callithrichid monkeys, invertebrates, poison dart frogs) were kept in a cage and in terraria within the Winter Garden, but these were removed in 2013, apparently because of incompatibilities between the temperature and humidity regime necessary for the animals and that needed by the plants. Possibly the preservation of the building's aesthetic and heritage value also played a role.
Since 2014 the Wintergarden has been used to house tropical butterflies - but only between April and October as it would be too expensive to maintain appropriate conditions for butterflies in this old house during the cold months. The Central-American butterflies are imported in chrysalis-form from butterfly farmers in Costa Rica.
The Winter Garden with butterflies can be accessed from the same hall that also gives access to the Small Monkey House and seems to be quite popular with visitors.
In this picture you can just slightly see that there is a fine mesh net present underneath the roof to prevent butterflies from flying up all the way to the glass roof and escaping if there is any damage or cooling down or heating up too much and dying when touching the glass.
