黑龙江省熊类年龄构成、性比及繁殖情况的初步研究

熊类是重要的狩猎动物,肉、皮、骨、脂均可利用,熊掌和熊胆尤为名贵,因而具有很高的经济价值。 目前,国际上对于熊类生态学的研究日益深入。近二十年来多次举行国际熊类研究专题讨论会并出版了论文集。研究方向集中于熊类的群体生态,行为生态及种群的管理方面并正朝着集约管理和合理利用的方向发展。     

中国云南西部小哺乳动物革螨的性比及年龄结构(英文)

1990～ 1 996年对中国云南西部 1 3个县进行了调查 ,从所捕获的 38种、30 2 3只小哺乳动物体表采集到革螨 70种、7485只。绝大多数革螨的雌性个体比例 ( 80 %～ 1 0 0 % )高于其雄性个体比例 (P <0 .0 1 ) ,唯贡山血革螨Haemogamasusgongshanensis和格氏血厉螨Haemolaelapsglasgowi例外。贡山血革螨的雄性个体比例高于其雌性个体比例 (P <0 .0 1 ) ,格氏血厉螨的雌雄比例接近 (P >0 .0 5)。在现场采集中 ,绝大多数革螨种类未见幼虫阶段。除柏氏禽刺螨Ornithonyssusbacoti及格氏血厉螨Haemolaelapsglasgowi的若虫比例 (分别为 62 .84%和 49.48% )较高外 ,绝大多数革螨的未成熟期 (主要是前若虫和后若虫 )比例( 0～ 1 2 .84% )明显低于成虫期比例 (P <0 .0 1 )。采自小哺乳动物体表革螨雌雄性比的不同可能与雌雄螨的吸血习性及孤雌生殖有关。绝大多数革螨在其宿主体表缺乏幼虫阶段以及若虫比例很低提示 :这些革螨的幼虫或若虫阶段可能不取食或不吸血 ,主要生活在宿主的窝巢内。另一种可能原因是某些革螨的雌螨可能直接产前若虫或后若虫 ,因此难以从宿主体表发现幼虫。     

SEX RATIO AND AGE STRUCTURE OF GAMASID MITES FROM SMALL MAMMALS IN WESTERN YUNNAN,CHINA*

Abstract A total of 70 species of gamasid mites (7485 individuals) were collected from the body surface of 38 species of small mammals (3023 individuals) during an investigation of 13 counties of western Yunnan, China, from 1990 to 1996. Most species of gamasid mites have more females (80% 100%) than males (P <0.01). Exceptions are Haemogamasus gongshanensis where males outnumber females (P < 0.01) and Haemolaelaps glasgowi where there are similar numbers of males and females (P > 0.05). No larva was found in most of the mite species. The proportion of individuals at the immature stages (mainly protonymphs and deutonymphs) in most mite species is small (0–12.84%) compared to the adults (P < 0.01). Exceptions are Ornithonyssus bacoti and Haemolaelaps glasgowi where 62.84% and 49.48% respectively are nymphs. The biased sex ratios may reflect the probable different bloodsucking preferences and parthenogenesis of the gamasid mites. The absence of larvae and a low proportion of nymph stages in most mite species probably reflect that the larvae or nymphs of most mite species are non‐feeding or non‐blood sucking and are in their hosts' nests. Another possibility is that some species directly produce protonymphs or even deutonymphs without eggs and larvae which makes it difficult to find the larval stage.     

桂林甑皮岩新石器时代遗址2例儿童的年龄问题

作者报告２例于桂林甑皮岩新石器时代早期遗址出土的正处于换牙期的儿童乳、恒牙更换及其被磨耗的状况,讨论了从他们的牙磨耗级估计的年龄与从其乳、恒牙更换关系估计的年龄的误差,并提出用现代人牙磨耗级估计史前人类年龄的意见．     

草兔的年龄鉴定和种群结构分析

根据１９９１年２－１０月猎自晋东南的２１２只和１９９０－１９９２年狩猎季节猎自山西和陕西省各地的１５１０只草兔眼晶体重的分布规律并参照繁殖资料,确定２２５毫克为区别１年以下及其以上个体的临界重量。秋－冬季种群中,当年兔占８６．３（７２．２－９３．５）％;随着繁殖季节的推移,当年兔的比例逐渐增加。在４０１１只标本中,雌性占５２．３％;其中１２２６只幼体和１９５只成体中分别有雌性５２．４％和５４．４％。在２－９月所获的９１只当年兔有雌性５０．５％,而成体中雌性则有５８．２％。     

对亲本受孕时生理状态与子代性比关系的某些理论的检验

在亲本受孕时生理状态与代性比的关系上存在着多种理论。在１９８８－１９９２年期间，作者用实验对其中的营养理论、氧化还原理论、酸碱理论和激素假说的部分观点进行了检验。结果表明：这些理论在某种速度上均具有合理性。作者还发现：这些理论之间是相互联系的。用一系列生理指标来描述双亲受孕时影响子代性比的生理状态，对于通过调节配种时双亲的生理状态来控制子代性比具有重要意义。     

SEX AND AGE SEGREGATION BY PHOCA VITULINA CONCOLOR AT HAUL-OUT SITES DURING THE BREEDING SEASON IN THE PASSAMAQUODDY BAY REGION, NEW BRUNSWICK

The size and composition of groups of harbor seals at two haul-out sites were studied during the breeding season of 1989, in the Passamaquoddy Bay region of Atlantic Canada. Evidence of segregation both by age and sex was found in the distinct composition of the two groups. One group contained mainly males and no pups, and the other had a sex ratio not significantly different from one and contained pups. The proportion of females increased at the nursery site with the onset of birthing in the region while the proportion of males increased through the breeding season at the other site. No increase in the number of adults, in total, was detected over the study period, suggesting that sexual segregation and not a change in haul-out frequency was responsible for the disparity in the sex structure of the two groups. The proportion of juveniles was significantly greater at the male dominated site than at the nursery site.     

佛坪自然保护区羚牛的种群数量与结构特征

１９９６年对佛坪自然保护区内的羚牛种群进行了数量调查,结果表明,保护区内羚牛的数量为４３５～５２７只,种群密度达到１．２９～１．５６只／ｋｍ２。羚牛种群的成体雌雄个体之比约为１∶０．５,明显地偏向雌性。在羚牛种群中幼仔占１２．２４％,亚成体占３５．０３％,成年雄性个体占１７．３３％,成年雌性个体占３５．４０％。该羚牛种群在１９９１年至１９９６年间的年均增长率为１８．４８％,明显高于１９８４至１９９１年间羚牛种群的年均增长率。保护区周边地区的生境不断丧失,迫使羚牛向保护区境内迁移,是保护区内羚牛种群数量在短期内迅速升高的原因。