Reproduction of the brush mouse and white-footed mouse in the central United States
Reproduction of the brush mouse and white-footed mouse in the central United States
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DOI：
10.2307/2423225
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发表时间：
1964-01-01
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影响因子：
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通讯作者：
BROWN, L. N.
中科院分区：
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作者：
BROWN, L. N.
在美国密苏里州南部用11/2年的时间研究了毛笔鼠（Peromyscus boylii）和白足鼠（P. leucopus）的季节繁殖周期。雌性刷鼠的繁殖活动主要发生在经期；2月- 4月和9月- 11月在1961年和1962年。繁殖低潮发生在夏季和冬季。雌性白足鼠在1961年也遵循类似的模式，但繁殖一直持续到1962年的仲夏时期。波氏斑蝶每次排卵平均黄体数为3.40个[正负]0.42个；平均胚胎数，3.39+ 0.81；胎盘疤痕平均为3.28（正负）0.35。白蛉每次排卵平均黄体数为4.46个[正负]1.24个；平均胚胎数3.74±0.51；胎盘疤痕平均为4.32+0.97。在繁殖季节，产仔数与父母体长（年龄）或怀孕时间相关的差异无法证明。在这两个物种中，怀孕期间的胚胎损失平均在5-10%之间。没有观察到凋落物的总吸收。产前损失的差异与体长（年龄）或生殖季节怀孕时间无关。胚胎从一个子宫角转到另一个子宫角是这些Peromyscus的常见现象。在1961年8月繁殖季节开始时，观察到雌性首次怀孕发生的同行性。成虫的睾丸周期明显为两年一次。通过睾丸重量和长度、精囊长度和睾丸组织学来证明。1961年和1962年的春季高峰出现在2月或3月，秋季高峰出现在10月。这些年来，6月和12月的性生活下降幅度最大。用同样的标准对成年白斑小蠊进行分析，结果显示1961年雄性生殖道的季节活动高峰在3月和9月，低谷在6月和10月。在1962年夏天，睾丸没有完全退化，到6月精子发生又恢复到高水平。在两种雄性中，睾丸活动的消退或精子发生的恢复不是同步的；有些人比其他人落后或领先一个月或更长时间。密苏里州的毛鼠和白足鼠一年两次的繁殖周期不能用光周期、环境温度或降水来令人满意地解释，尽管这三者可能都有一定的重要性。圈养出生的12窝毛刷鼠平均产仔数为2.80[正负]0.41。单次非泌乳妊娠期为23 d，泌乳妊娠期为26 ~ 32 d。已知年龄的波氏p.b ylii睾丸中精子出现的最早年龄为60天。摘要作者：作者
The seasonal reproductive cycles of the brush mouse (Peromyscus boylii) and the white-footed mouse (P. leucopus) were studied for 11/2 years in southern Missouri. Breeding activity of female brush mice occurred primarily during periods; Feb.-April and Sept.-Nov., in 1961 and 1962. Lows in reproduction occurred in the summer and winter. Female white-footed mice followed a similar pattern in 1961, but but breeding continued through the mid-summer period of 1962. For P. boylii the average number of corpora lutea per ovulation was 3.40 [plus or minus] 0.42; the mean number of embryos, 3.39+ 0.81; and placental scars averaged 3.28 [plus or minus] 0.35. For P. leucopus the average number of corpora lutea per ovulation was 4.46 [plus or minus] 1.24; the mean number of embryos, 3.74 +[plus or minus] 0.51; and placental scars averaged 4.32+0.97. Differences in litter size correlated to parent body length (age) or to the time of pregnancy during the reproductive season could not be demonstrated. Embryonic loss during gestation averaged between 5-10% of ova ovulated in both species. Total litter resorption was not observed. Differences in prenatal loss could not be correlated with body length (age) or with the time of pregnancy during the reproductive season. Transmigration of embryos from one uterine horn to the other was a common phenomenon in these Peromyscus. Synchrony of females in the occurrence of first pregnancy was observed at the onset of the breeding season in August, 1961, for P. boylii. A marked biannual testicular cycle occurred in adult P. boylii. demonstrated by the criteria of testis weight and length, seminal vesicle length, and testis histology. The spring peak occurred in Feb. or March and the fall peak occurred in Oct. during 1961 and 1962. Greatest sexual decline was recorded in June and Dec. of these years. Use of the same criteria on adult P. leucopus revealed peak seasonal activity of the male reproductive tract in March and Sept., and lows in June and Oct. of 1961. During the summer of 1962 full regression of testes did not occur and spermatogenesis returned to high levels by June. Regression of testicular activity or resumption of spermatogenesis was not synchronous in males of either species; some lagged behind or preceded others by a month or more. The biannual nature of reproductive cycles of the brush mouse and white-footed mouse in Missouri cannot be explained satisfactorily on the basis of photoperiodism, environmental temperatures, or precipitation, although all 3 are probably of some importance. For 12 litters of brush mice born in captivity the mean litter size was 2.80 [plus or minus] 0.41. A single nonlactating gestation period of 23 days was recorded, and the length of lactating gestation ranged from 26-32 days. The earliest age recorded for the appearance of spermatozoa in the testes of known-age P. boylii was 60 days. || ABSTRACT AUTHORS: Author