Fruit color and fruit size of bird-disseminated plants in Japan

Abstract

Fruit color, fruit size and phenology of bird-disseminated plants were examined in different climatic zones of Japan and the relationships between the plants and frugivorous birds were disscussed. Black fruit was the most common in warm-temperate areas and red was the most common in cool-temperate and subarctic zones. Red was more dominant in the lower layer of the forests in all climatic zones. Bicolor fruits were frequent in trees and were not found in herbs. Both in warm- and cool-temperate zones conspicuous fruits which are red and bicolored display were more frequent in summer than in winter. The diameter of most fruits were 4–11 mm. Fruits in warm-temperate were somewhat bigger than those in cooltemperate zone. In forest strata the fruits of shrubs were smaller than those of trees and herbs in width. However I found no relationships between fruit size and fruit color. The frugivorous birds could have influenced not only the evolution of seasonal differences in the proportion of fruit color between warm-temperate and cool-temperate region, but also affect the fruit size.