布氏田鼠标志种群的繁殖参数

THE REPRODUCTIVE PARAMETERS IN THE MARKED POPULATIONS OF BRANDT'S VOLE

采用标志重捕和染色观测法跟踪了内蒙古典型草原区布氏田鼠野外种群 ,按绝对时间年龄研究其种群繁殖参数。结果表明 :4～ 5月份出生的雄鼠能在当年达到性成熟 ,性成熟发育历期约为 1 5个月 ,6月后出生的雄鼠当年达不到性成熟。在达到性成熟的当年雄鼠中 ,多数个体再度转入性休止期 ,其平均繁殖结束时间要比越冬雄鼠早 1个月 ,而越冬雄鼠则在整个繁殖期保持性活动状态。雌鼠性成熟发育历期约为 1个月 ,首次产仔时间约为2月龄。雌鼠在一年中的产仔窝数与其年龄有关 :越冬鼠能产 3～ 4窝 ,4月份出生的雌鼠能产 2～ 3窝 ,5月份出生的雌鼠当年能产 1～ 2窝 ,6月份出生的雌鼠能产 0～ 1窝 ,7月份之后出生雌鼠当年不参加繁殖。在自然条件下 ,布氏田鼠一生中最多能产

Marking-recapture and directly sighting techniques were used to census wild populations of Brandt's vole (Microtus brandti) in the typical steppe in the Inner Mongolian grassland. The reproductive parameters were analyzed based on absolute age. Results revealed that males born in April and May can reach sexual maturation at about 1.5 month old, while males born in June, July, and August cannot reach sexual maturation in current year. However, only a part of matured-newborn males can remain sexual active status, while over-winter males remain sexual maturation across the whole breeding season. Current analysis also detected that females born in April, May, and June can reach sexual maturation at about 1 month old and firstly breed at about 2 month old, and females born in July and August can not breed in current year. The number of litters that a female can breed in current year is related with its age: over-winter voles can breed 3-4 litters, and those born in April, May, and June can breed 2-3, 1-2, and 0-1 litter(s) in current year, respectively. A female can breed 4 litters, as a maximum number, during its life under filed condition.