Folivory in Fruit Bats: Leaves Provide a Natural Source of Calicum

Leaves are an important dietary source of carbohydrates and protein, and an especially rich source of calcium for bats. Most studies of leaf eating by fruit bats have suggested that only male bats feed on leaves. In this study, 23 wild-caught Tongan fruit bats (Pteropus tonganus) were used in feeding trials conducted in an outdoor enclosure. The number of leaves and percentage of each leaf eaten were recorded for each bat on a daily basis, and these data were then multiplied by a calcium constant that was derived from a chemical analysis of leaves from Callophylum neo-ebudicum. Leaves of C. neo-ebudicum that were available in the enclosure were consumed by 82.7% of the bats. Overall, males consumed leaves in greater quantities and with higher frequency than females. Bats that consumed leaves on a regular basis consumed up to 46% more calcium to their diet compared with bats that did not regularly consume leaves. Leaves may represent a readily available, widely used, concentrated source of minerals for foraging bats, and have the potential to contribute significantly to the total amount of ingested calcium.     

Geophagy as a correlate of folivory in red-handed howler monkeys (Alouatta belzebul) from eastern Brazilian Amazonia

Howler monkeys, Alouatta spp., are the most folivorous of neotropical primates (Platyrrhini), although Amazonian red-handed howlers (Alouatta belzebul) are relatively frugivorous. The feeding ecology of a free-ranging group of A. belzebul was monitored at a site in eastern Brazilian Amazonia over a ten-month period (November 1997 to August 1998). The first half of the study period encompassed the peak of the wet season, during which the study group's diet was predominantly frugivorous (scan sample records: 53.5% fruit, 40.8% leaves), and the second half, the transition from wet to dry season, characterized by a marked shift to folivory (18.9% fruit, 77.9% leaves). This shift was accompanied by a marked increase in mature, as opposed to flush leaves, which are relatively rich in secondary compounds. Ingestion of soil from termitaria was recorded on a total of 26 occasions, all of which occurred during the second half of the study period. Soil from termitaria was relatively rich in elements such as Ca and Na and in organic carbon, in comparison with that from the forest floor. The extent to which the monkeys ingested soil for their mineral supplements, or as an aid for the digestion of leaves, in particular the absorption of secondary compounds, remains unclear. The marked correlation with the observed patterns of folivory suggests that the latter function may have been the primary motive for geophagy in this species.     

Chemical Composition of Fruits and Leaves Eaten by Short-Nosed Fruit Bat, Cynopterus sphinx

We evaluated organic and macromineral composition of selected fruits and leaves consumed by the short-nosed fruit bat, Cynopterus sphinx in South India. Results of principal components analysis (PCA) comparing soluble carbohydrates, crude protein, and crude fats indicate a higher percentage of protein in leaves and a higher percentage of carbohydrates and lipids in fruits. However, results of a paired t test comparing these organic components indicated no differences between fruits and leaves. Among the fruits analyzed, Musa x paradisiaca had the highest percentage of carbohydrates, and Psidium guajava had the highest percentage of lipids. Leaves of Cassia fistula, Moringa oleifera, coccinia cordifolia, and F. religiosa had the highest percentage of protein. PCA of selected macrominerals (Ca, Na, K, and P) indicate higher levels of Ca in leaves than in fruits. Results of t tests comparing these macrominerals revealed a difference between fruits and leaves for Ca, but not for the other macrominerals. Among the leaves analyzed, Ca was highest in mature leaves of C. fistula and lowest in leaves of F. religiosa. Leaves of M. oleifera and fruits of Achras sapota were highest in sodium. Among fruits analyzed for macrominerals, Ca was highest in F. bengalensis and lowest in Prosopis juliflora, A. sapota, and M. x paradisiaca. Potassium levels were highest in leaves of C. cordifolia and fruit pods of Prosopis juliflora. Phosphorus content was highest in leaves of M. oleifera and fruits of M. x paradisiaca. The relatively high concentrations of protein and calcium in leaves eaten by C. sphinx supports the hypothesis that leaves are important dietary sources for this plant-visiting bat.     

Vertebrate Herbivory on Eucalyptus—Identification of Specific Feeding Deterrents for Common Ringtail Possums (Pseudocheirus peregrinus) by Bioassay-Guided Fractionation of Eucalyptus ovata Foliage

Factors determining the acceptance of Eucalyptus ovata foliage by common ringtail possums (Pseudocheirus peregrinus) were studied. Bioassay-guided fractionation was used with foliage from both browser-susceptible and browser-resistant trees to identify the chemical components underlying the resistance. In foliage from browser-resistant trees, the deterrent principles were contained in the base-soluble fraction of the chloroform extract. Further fractionation of this material yielded polar and nonpolar fractions that contained acylphloroglucinol derivatives, and from the polar fraction we isolated macrocarpal G. Addition of this compound to an artificial diet at a concentration of 2.1% of dry matter resulted in a 90% reduction of voluntary food intake compared with solvent-treated controls. This is the first time that a specific compound in Eucalyptus has been shown to inhibit feeding of any marsupial folivore.