A bat survey in the Jean Massart Botanical Garden was carried out during the summer of 2019 by Plecotus, bat working group of the nature conservation NGO Natagora, with the use of manual and automatic recording techniques. It showed the presence of 10 species on the site, including the Brown Long-eared Bat, Plecotus auritus (L.), detected in several locations within the garden. Concurrently, an inventory of arthropods, conducted since 2013 on the site, detected the presence of numerous wings of Mormo maura (L.), a large moth, at the entrance of an old underground passage frequented by P. auritus. This observation suggests predation by P. auritus on this species of moth, which can thus be added to the diet of the bat. [ABSTRACT FROM AUTHOR]