繁殖期高原鼠兔的行为时间分配与后代存活率的关系

2002年4-8月份,在中国科学院海北高寒草甸生态系统定位站附近,采用标志流放、直接观察法和解剖法对青藏高原特有的植食性小哺乳动物———高原鼠兔(Ochotonacurzoniae)的行为时间分配、繁殖特征和后代存活率等方面进行了研究。结果表明,雌、雄成体平均地面活动时间占总时间的比例分别为88.67%和89.88%,在不同的繁殖时段,成体的各种行为时间分配存在显著的变化,并影响后代的存活率。幼体从出生到15d的存活率和雌、雄性成体的每次移动距离以及雌性成体的地面活动强度都显著的正相关;从15d到45d的存活率和雄性成体的地面活动强度、观望强度显著的正相关。在相同的观察时期,高原鼠兔雌、雄成体的一些行为时间分配存在显著差异,如雄性成体地面移动距离、频次在繁殖前期显著的高于雌性成体;雄性成体的观望强度在6、7月份显著高于雌性成体。说明雄性成体在领域防卫中较雌性成体承担更多的责任,雌、雄成体在育幼活动中的繁殖投入存在互补性。

Relationship between activity budgets of the plateau pika Ochotona curzoniae and survival rates of offspring

The plateau pika (Ochotona curzoniae, also called the black-lipped pika) is a small non-hibernating diurnal lagomorph which inhabits alpine meadows in Qinghai-Xizang plateau (Tibetan), China. During the period April to August 2002, time budget of behavior and survival rates of their offspring were studied in the Haibei Research Station of Alpine Meadow Ecosystem, using mark-recapture, direct field observations and anatomical methods. The results showed that above-ground activities for males and females from 07:00 to 18:00 were 89.88% and 88.67%, respectively. Activities on the surface during the early breeding period was significantly higher than that of the later breeding period in both mature males and females. Activity on surface had a direct effect on the survival of juveniles. The survival rate of juveniles from birth to 15 days old had a significant positive correlation with mature females on surface activity. On the other hand, the surviving rate of juveniles from 15 to 45 days old was positively correlated with surface activity of mature males. Meanwhile, the distance of each movement of mature plateau pika was positively correlated with the survival of juveniles from birth to 15 days of age. The observation behavior of mature males had also a significant positive correlation with survival of juveniles from 15 to 45 days of age. The results are in accord with predictions that the reproductive cost of parents would influence their reproductive success. In the same period, there was an apparently difference between the activity budget of mature males and females. Mature males showed significantly higher frequency (cases/15 min), distance of locomotion from April to May, 2002 and the intensity, frequency (cases/15 min) of observation behavior from June to July, 2002 compared with mature females. The results indicated that, mature males spend more time on the defence of territory than mature females. In conclusion, there is a mutually complementarity between the reproductive investment of mature males and females in nursing off-spring.