ニホンリスによるオニグルミ種子の貯食および分散

抄録

Hoarding behaviour of Japanese squirrels (Sciurus lis Temminck) was studied using walnuts (Juglans airanthifolia Carr.) attached radio transmitters. A hundred of walnut seeds were provided on the feeding stands in the walnut forest from September to December of 1992. Squirrels immediately ate 35 walnuts near the feeding stand, and 60 of them were scatter-hoarded. The hoarding site tended to be upper part of the slope than the feeding stand. The distance from the feeding stand to hoarding sites ranged from 1-62m. Thirty-eight of hoarded walnuts were retrieved by squirrels later, but 15 were stolen by wood mice (Apodemus speciosus Temminck). Consequently, 7 of them were left at the hoarded site until May, 1993, when starting the germination. The scatter-hoarding by Japanese squirrels had an important role for seed dispersion of walnuts.