摘要
在川西平原利用标志重捕、夹捕解剖和半自然条件下笼养的方法，提供了１９８９～１９９５年大足鼠种群雄性和雌性个体处于繁殖状态的比例、胎次数、每胎幼仔数、幼年个体的补充和发育等有关繁殖的基本资料。结果显示，大足鼠极灵活的繁殖策略提高了这个物种幼年个体的存活，使该物种在可预见而频繁的周期性变化的农田环境中能够保持相对稳定的种群。大足鼠的繁殖特征主要有：处于繁殖状态的雄性比例较大（平均０４９１，９５％置信区间０４５１和０５３４），怀孕雌性的比例较小（平均０２２７，９５％置信区间０２１３和０３０１），较高和相对稳定的繁殖能力（每年４胎，每胎８２４５±０４５２只），雌性幼仔较慢的生长和性成熟（４月），以及幼年个体加入种群与春季的小麦和秋季的水稻成熟相同步。这些繁殖特征使得大足鼠的繁殖活动集中在有利的时间。结果，虽然伴随繁殖活动雌雄性的个体质量下降，但仍能在短暂的时间里恢复到原来的水平。将大足鼠的胎仔数与一些关于中国啮齿动物繁殖参数地理变异的研究进行了分析比较，发现后者提供的资料尚不足以支持中国所有啮齿动物都有“胎仔数随纬度增加”的过分简单的一般结论。每一个物种种群都有自己的最优胎仔数，但最优胎仔数不一定随?
The extremely flexible reproductive ta ctics of Rattus nitidus facilitate juvenile survival and enable this species of rodent to maintain remar kably stable population despite predictably periodical and frequent fluctuations in its agricultural environment. Mark-recapture,trap-dissection and captive feeding in semi-natural condition provide data on proportions of the male and female individuals in reproductive condition,the number of litters per year,litter size,recruitment and development of juveniles for a population of R. nitidus in the Western Sichuan Plain from 1989 through 1995. Reproductive tactics are characterized by greater proportion of the males in reproductive condition (mean 0.491 with a 95% confidence interval of 0.451 and 0.534),smaller proportion of the pregnant females (mean 0.227 with a 95% confidence interval of 0.213 and 0.301),higher and relatively stable reproductive effort (4 litters per year,and an average of 8.245 (0.452 young per litter),slow growth and maturation of female young (about 4 months from birth to sexual maturity),and synchronizing recrui tment of juveniles following ripening of wheat (in spring) and rice (in fall). This combination of reproductive tactics enables R. nitidus to confine repr oduct ion mainly to favorable period,with the result that although adults of both sex es showed a loss of body mass associated with reproduction,body mass can recover to the level before reproduction quickly after breeding. At the same time we a nalyzed and compared the litter size of R. nitidus with other studies on region alvariations of reproduction parameters of rodents in China. Our critical examination of the data presented by some other authors shows that they do not provid e sufficient support for the over-simplified generalization of "latitudinal in crease in litter size" for all of rodents in China. Every population has its own optimal litter size. But the optimal litter size does not necessarily increase with latitude. While studying life-history traits like litter size on large scales,we prefer the diversity of life-history traits to over-simplified generaliz ations of a single life-history trait like litter size.
出处
《兽类学报》
CAS
CSCD
北大核心
1999年第3期183-196,共14页
Acta Theriologica Sinica
基金
The National Natural Foundation of China has supparted the project with grants 3880589 and 39270121
关键词
大足鼠
繁殖
种群生态学
川西平原
Himalayan rat( Rattus nitidus)
Recruitment
Diversity of life histories
Number of litters
Litter size
Reproduction
