食物源距离对中华姬鼠贮藏策略的影响

摘要

The effect of food source distance on hoarding strategy of South China field mice (Apodemus draco) was tested in a semi-natural enclosure,and two predictions based on the Rapidly Sequestering Hypothesis and Optimal Cache Spacing Model were examined:(1) Seeds would be scatter-hoarded near the three test sites respectively regardless of distance between nest and test sites;(2) With increasing of distance between cache site and nest,the proportion of larder-hoarded-seeds would decrease.In our study,eight South China field mice were selected and tested successively,three test sites were placed with 20 seeds respectively once a time.After 14 hours free movement of the mice,the fate of seeds was recorded.The seed fate was classified into three types:(1) eaten in nest;(2) eaten out nest;(3) larder-hoarded;(4)scatter-hoarded.The results showed that scatter-hoarding behavior is the main caching strategy of A.draco,and there was no significant difference in the number of seeds scatter-hoarded in the three test sites,supporting prediction 1.The proportions of seeds that were larder-hoarded decreased with the increase of distance between test site and the nest (1 m ∶6.25％;5 m∶ 1.88％;13 m∶ 1.25％),supporting prediction 2.Our results indicated that with the increased predation risk,A.draco tend to reduce the number of seeds eaten and cached.%在围栏条件下,检验食物源距离对中华姬鼠贮藏策略的影响,并检验根据快速隔离假说和最优贮藏空间分布模型做出的两个预测:(1)3个释放点无论距离远近,种子均先被大量分散贮藏在各个释放点周围;(2)随着释放点远离巢穴,种子被集中贮藏的比例下降.结果发现:分散贮藏是中华姬鼠的主要贮藏方式,3个释放点种子被分散贮藏的数量无显著差异,这个结果支持预测(1);3个种子释放点(1m,5 m,13 m)被集中贮藏的比例分别为(1 m∶ 6.25％;5 m∶ 1.88％;13 m∶1.25％),说明被集中贮藏的种子数量随种子释放点与巢穴距离的增大而逐渐减少,这个结果支持预测(2).本研究表明中华姬鼠应对捕食风险升高的策略是降低取食量和贮藏量.