赤狐气味对高原鼠兔繁殖的影响

The Influence of Red Fox′s Odor on the Reproduction of the Plateau Pika

在野外条件下,利用赤狐的粪尿气味增加高原鼠兔的捕食风险,研究捕食风险对高原鼠兔繁殖的影响。结果表明,作为衡量高原鼠兔繁殖投入大小的定量指标,成体高原鼠兔的体重变化在捕食风险处理样方与对照样方之间没有明显的不同,随着繁殖期的延长,两样方内雌雄个体的体重均显著减少,说明捕食风险对高原鼠兔的繁殖投入无明显影响,因此,捕食风险对幼体的生长、发育也无明显的作用。捕食风险增加后,高原鼠兔平均每个雌性成体拥有的后代数目、性比和居留率与对照样方比较均无明显不同,但是由于扩散等原因使每个雄性成体拥有的后代数、繁殖期结束后幼体的性比有明显的差异。以上结果并未显示出捕食者气味作为捕食风险对高原鼠兔的繁殖产生抑制作用,其主要原因是捕食风险的类型不同和研究期间高原鼠兔本身承受的捕食风险较大,高原鼠兔可能通过行为变化调节捕食风险增加对其产生的不利影响。

The influence of the predation risk by using feces and urine of the red fox on the reproduction of the plateau pika ((Ochotona curzoniae)) was studied and the reproduction suppression hypothesis was verified in the field. The results showed that the body weight of the pika, which was the index to assess the reproduction investment of the pika, has no significant difference between treatment and control plots. The red fox′s odor could not influence the reproduction investment of the pika. During the early period of their reproduction, both of male and female obviously increased their reproduction investment, but the investment of female was much higher than that of male during the late period of reproduction, because the male finished his mating activity and spent less time to care for the offspring than female. The reproductive success of the female, sexual ratio and resident rate for plateau pika have no difference between the treatment and control plots, but the reproductive success of male and the sexual ratio of the offspring for plateau pika were different between two plots. The pika could make decision and behaviorally decrease the predation risk. The results did not supported the reproduction suppression hypothesis and the predation risk did not suppress the reproduction of the plateau pika significantly.