The single most important food source for Pteropus rufus at Berenty, in south-east Madagascar, is the pollen of Agave sisalana, a commercial species introduced to the area 60 y ago, which was widely available and constantly eaten by the bats during this 28-mo study. The diet of the bats at this site is unique in this respect when compared with P. rufus elsewhere in Madagascar and with other Pteropus species. The dietary breadth of P. rufus at Berenty is narrow, consisting of only 14 plant species, identified through microsopic faecal analysis and direct field observations, and three unidentified ones. The bats also eat locally cultivated and introduced fruits (Mangifera indica, Psidium cf. cattleianum, Sclerocarya caffra, Cordia sinensis and Hylocereus species) and native and endemic forest species (Tamarindus indica, Celtis philippensis, Ficus megapoda, F. grevei, F. pachyclada and Grewia species). The majority of the plant species used by P. rufus for food are located within the gallery forests of the Mandrare valley. No evidence of adjacent endemic spiny forest species was identified in their diet. Thus, conservation of the remaining gallery forest as well as retention of the sisal plantations is important to maintain the food sources of P. rufus at this site.