This study is an assessment of the use of mealworm dispensers as environmental enrichment devices for Rodrigues fruit bats (Pteropus rodncensis). Captive animals frequently receive easily consumed food at set times and locations, which often minimizes the time they spend searching for and processing food. The mealworm dispensers used in this study provide an unpredictable food source, which allows the link between foraging and feeding to be reinstated. Mealworm dispensers were placed into the Rodrigues fruit bat enclosure at the Jersey Wildlife Preservation Trust and the behaviour of the bats recorded over 14 days. For 7 days the dispensers were empty but, for the remaining 7, 20 mealworms were placed in each dispenser. The number of bats feeding declined with increasing time from initial food presentation in all cases, but the presence of mealworms in the dispensers decreased the rate of decline. In addition, the number of bats active within 20cm of the food in the dishes and on the heater tops increased significantly when mealworms were present. Although the presence of mealworms had no effect on the number of flights made by the group of bats as a whole, both the number of bats on the enclosure floor and the amount of aggression observed in the enclosure decreased when mealworms were present.

Installation of mealworm dispensers meant that the bats found food items as a consequence of their natural exploratory and foraging behaviour, and as such they provided important ingredients for approximating a natural habitat and improving welfare.

The Rodrigues fruit bat Pteropus rodricensis is endemic to Rodrigues Island, the smallest of the Mascarene Islands in the Indian Ocean. The species is categorized as Critically Endangered on the IUCN Red List. A study between February 2001 and February 2002 identified 10 roosts, four previously unrecorded. Roost sites were located in the north and south of the island, all within forested valleys. Sixteen counts of each roost site, evenly spaced throughout the study period, showed dramatic changes in individual colony numbers, suggesting movement between roosts. Simultaneous counts of all colonies resulted in a minimum population estimate of 5,076, which is substantially higher than previous estimates of the species. This is believed to be due to a population increase since the last count, newly identified roosts and the movement of bats into different areas, allowing more accurate counts to be made.