FEEDING ECOLOGY OF THE NORTHERN RYUKYU FRUIT BAT, PTEROPUS-DASYMALLUS-DASYMALLUS, IN A WARM-TEMPERATE REGION

The warm-temperate fruit bat, Pteropus dasymallus dasymallus consumed at least 17 species of fruits, five of flowers, nine of leaves, one of bark and eight of insects. Soft fruits formed the bulk of its diet. Ficus eaten by the bat fruited asynchronously among individuals of the same species. In these species, the ratios of trees bearing ripe fruit to all trees examined each month were very low except for F. erecta. On the other hand, some plant species showed synchronous fruit production over a short period. Both types of plants supply fruits in every season. Seasonal dietary shifts and food choice were evident, and flowers, leaves or insects formed a small but nutritionally important component of the diet of the bat. The frequency of mastication was 124-155 per one pellet produced within a few minutes. The bat extracted and swallowed 61-82% of the fruits' wet weight and 58-73% of the insects' weight. The swallowed juice passed through the digestive systems in only 34 min on average. The bat ingested 0-5 times its body weight in figs per day. It is probable that such a low food intake is adapted for the seasonal changes of food availability in the warm-temperature region.