Energy (Im-)Balance in Frugivorous Lemurs in Southern Madagascar: A Preliminary Study in Lemur catta and Eulemur rufifrons × collaris

The reproductive cycle of several lemur species is synchronized by photoperiodic changes and it is attuned to the seasonal fluctuations in food supply. Nevertheless, irregular periods of food shortage occur in Madagascar, which can result in a negative energy balance and reduced fitness, especially in frugivorous species. Here, we tested whether ring-tailed lemurs (Lemur catta) and brown lemurs (Eulemur rufifrons × collaris) use fat stores to maintain their energy balance in a gallery forest of Madagascar (Berenty Reserve). We assessed the energy intake from weight-based estimates of food intake (mouthful count) and macronutrient contents in the diet during dry and wet months. The metabolizable energy ingested by these frugivorous/folivorous species was high during the late wet season, but it was insufficient to meet their energy requirements during the dry season. These preliminary data suggest that these lemurs must store sufficient amount of fat mass during the period of food abundance to meet their maintenance requirements and to cope with the energetic burden of the mating season. Estimates based on models assuming no fiber digestibility during the dry season are consistent with the prediction that brown lemurs should supplement their daytime diet with nighttime feeding in addition to the use of body fat stores.