Print PageGut retention time (GRT), which is defined as the time needed for seeds swallowed by frugivores to pass the digestive tracts, may affect both the germination rate and spatial distribution of seeds. Previous GRT studies indicated that the source and amount of fibers in the diet may cause significant variation in the GRT of primates which are important seed dispersers because they consume a large amount of fruits and defecate lots of viable seeds, and germination rate of seeds. This study was set to investigate the relationship between the fiber content in diets and GRT in hindgut-fermentated primates, and the effect of GRT on germination rate of seeds with different types of dormancy. We compare the effect of fiber content in diet of on GRT in four hindgut-fermentated primate species (Macaca cyclopis, M. fascicularis, Hylobates lar, and Pongo pygmmaeus). In addition, we examined the effect of GRT on seed germination of non-dormancy seeds (Ficus septica) and shallow dormancy seeds (Trema orientalis).
Results/Conclusions
The results showed that the GRT was longer for digesting higher fiber ratio diets in Hylobates lar (20.6±0.6/24.5±0.7 hr) and P. pygmmaeus (124.7±9.0/146.5±11.4 hr), but not in macaques. The germination rate of F. septica seeds after passing the gut of P. pygmmaeus was lower (0.27±0.10) and germination time needed was longer (18.1±0.8 days) than controls (0.81±0.22; 11.0±1.6 days). The germination time of F. septica seeds correlated positively with GRT in M. cyclopis (R2 =0.817) and P. pygmmaeus (R2 =0.794). However, the germination rate of Trema orientalis seeds after passing the gut of M. cyclopis tended to be lower than control. Moreover, the germination time of T. orientalis seeds correlated negatively with GRT in P. pygmmaeus (R2 =0.401). In conclusion, GRT increased with fiber ratio in the diets in P. pygmmaeus and H. lar, and GRT had different effects on seed germination in seeds with different dormancy types.
