Potential of Myrica rubra seed dispersal by spitting out by sika deer during rumination and its effect on germination rate after dispersal

Some ruminants spit out seeds that are too large to pass through the third stomach. Seed dispersal by spitting out has not been reported in sika deer (Cervus nippon), and its function as a seed disperser has been underestimated. This study examined the effects of different seed sizes on the time taken to spit out seeds by feeding Myrica rubra fruits to captive individuals. In addition, germination tests were conducted to evaluate the factors affecting the germination ratio by incubating pulp-free seeds under various environmental conditions. The results showed that 74% of the wild M. rubra seeds were spat out within 24 hours, and no seeds retaining their original shape were detected in the feces. The presence or absence of pulp did not affect the germination ratio. in vitro germination tests revealed a positive effect of temperature and a negative effect of treatment time on the germination ratio. When M. rubra seeds were soaked in rumen contents, their germination ratio was lower than that soaked in distilled water. Further field research is needed to determine the effectiveness of M. rubra seed dispersal by spitting out sika deer.