摘要 : A study was conducted during 1992-94 to investigate fruiting phenologies and competition for seed dispersal in species of Miconia and Psychotria of Barro Colorado Island and Soberania National Park, central Panama. These two gener... 展开 A study was conducted during 1992-94 to investigate fruiting phenologies and competition for seed dispersal in species of Miconia and Psychotria of Barro Colorado Island and Soberania National Park, central Panama. These two genera accounted for 18and 27%, respectively, of 1096 fleshy fruits found in regurgitation or faecal samples taken from 2054 birds of 103 species netted in the forest understoreys. Two species of manakins accounted for 62% (123/200) of all Miconia fruit taken, while 3 speciesof manakins and 3 species of migratory thrushes accounted for 97% (282/292) of all Psychotria fruits taken. A high potential for intrageneric competition for seed dispersal existed for both genera. Null model analyses indicated that the fruiting phenologies of Miconia (14 species) were segregated in time, while fruiting of Psychotria (21 species) was highly aggregated. The Miconia were found in up to 24% of the diet samples for the 2 manakin species, indicating that Miconia may be a critical resource for both species. The Psychotria fruited when the diversity of understorey fruits was greatest, suggesting a high potential for both intra- and extrageneric competition. The abundance and nomadism of the 6 bird species that consumed most Psychotria fruit peaked when the Psychotria fruited, supporting the enhancement hypothesis. 收起