共查询到10条相似文献,搜索用时 31 毫秒
1.
高原鼠兔种群的性比 总被引:6,自引:1,他引:5
The sex ratio (♂ / ♀ ) of plateau pika's (Ochotona curzoniae) population was studied by re-captured method in the region of the Haibei Mpine Meadow Ecosystem Research Station, Northwest Institute of Plateau Biology, the Chinese Academy of Sciences from April of 2001 to August of 2002. The result showed that there was no significant difference from 1:1 in adult's sex ratio in whole breeding season, whereas the sex ratio of juvenile had some fluctuations among different age stages. The sex ratio of the second litter varied significantly from embryo to 60-day-old, but no difference at the first and the third litter. We concluded it was caused by conflict between maternal strategy and juvenile's strategy. No significant differences of sex ratio were found both in adult and juvenile between 2001 and 2002. The sex ratio of plateau pika before and after overwintering did not vary. In summary,we proposed that sex ratio of plateau pika's population was not influenced by exogenous factors, but some serf-regulation mechanisms may be involved. 相似文献
2.
贺兰山保护区冬季岩羊集群特征的初步分析 总被引:9,自引:1,他引:8
Group size and composition of blue sheep (Pseudois nayaur) were studied in the Helan Mountains, Ningxia Autonomous Region from November to December 2003. We scanned mountain slopes with binoculars and observed with 20 - 60 x spotting-scope. A total of 310 herds of blue sheep and 1 336 individuals were observed during the study period. Blue sheep were frequently seen in small herds of 2 to 8 individuals, which represent 94.8% of total herds observed. Herds consisting of 9 individuals or more represented 5.2%. The largest herd we observed numbered 51 individuals. Mean group size was 4.2 individuals. Blue sheep herds can be divided into three types: male herds (composed solely of males), female herds (consisting of females with or without juveniles of both sexes), and mixed herds (including adult males, females, and subadults). Among the 310 herds, female herds were counted 150 times (48.4%}, mixed herds 154 times (49.7%), and male berds 6 times (1.9%) . Of 1 336 blue sheep classified by sex and age, adults, subadults and juveniles composed 64.1%, 20.8%, and 15.1% respectively. The female: male ratio of adults was 1:0.73. The ratio of adult females to juveniles was 1:0.56, which is higher than the ratio recorded in spring ( 1:0.43) or summer ( 1:0.44). The results showed that the Helan Mountains State Nature Reserve has succeed in protecting blue sheep. 相似文献
3.
OMKAR AHMAD PERVEZ SATYENDRA K. SINGH 《Insect Science》2005,12(5):375-379
The developmental parameters, namely developmental periods, larval survival, adult emergence, growth index, developmental rate and sex ratio in terms of female proportion in a population of two aphidophagous ladybirds, namely, Coelophora biplagiata (Swartz) and Micraspis discolor (Fabricius) were investigated, using three aphid species as prey. The immature stages of C. biplagiata were significantly affected by prey quality and developed fastest when fed on Aphis craccivora followed by Aphis gossypii and Rhopalosiphum maidis. The order of prey suitability in terms of developmental rate of immature stages of M. discolor was just reversed. The adult females were heavier than males, while pre-pupae were heavier than pupae in both ladybirds. The sex ratio of adult emergence, though female-biased in both ladybird species, was not significantly affected by prey quality. 相似文献
4.
笼养红斑羚生态生物学的初步观察 总被引:1,自引:0,他引:1
This study presents the results of a demographic analysis of 20 years of birth and death records of red gorals kept at the Shanghai Zoo.The age of the first successful breeding,sex ratio at birth,seasonality of reproduction and mortality rate are presented.The females or males of red goral born in captivity can give their first birth at the age of 2 or 3 separately.The births mainly occurred from May to July and peaked in June.Ratio of females to males at birth was 2.36:1.1 The mortality rate for infants and adults were 23.1% and 11.8%,respectively while there was no sub-adult death recorded during the 20 years period.There was a definite relation between mortality rate and seasons and mainly in July. 相似文献
5.
Genetic structure and differentiation of Reaumuria soongorica (Pall.) Maxim population from the desert of Fukang, Xinjiang, were assessed by means of random amplified polymorphic DNA (RAPD) markers. High genetic diversity and differentiation were revealed in the population of R. soongorica by 15 random primers. One hundred and thirty-six individuals from seven subpopulations were sampled in the study. Seventy-one loci have been detected, and among them 69 were polymorphic. The mean proportion of polymorphic loci (PPB) was 97.18%. The analyses of Shannon information index (0.307 5), Nei抯 gene diversity (0.312 7) and GST (0.312 0) indicated that there were more genetic variations within the subpopu-lations than those among the subpopulations. The results of AMOVA analysis showed that 61.58% of the genetic variations existed within subpopulations, and 38.02% among the subpopulations. The gene flow among the subpopulations of R. soongorica (Nm = 1.102 8) was much less than that of the common anemophytes (Nm = 5.24), so genetic differentiation among the subpopulations occurred to some extent. Additionally, through the use of clustering and the correlation analyses, we found that the genetic struc-ture of natural population of R. soongorica was related to some ecological factors (soil factors mainly) of the oasis-desert transition zone. The genetic diversity level of R. soongorica had negative correlation with the content of total soil P and Cl- significantly (P<0.05). On the contrary, it had significant positive correlation with CO32- (P<0.05), showing that the distribution of the individuals of R. soongorica in the sampled areas correlates with certain soluble salt. Furthermore, the genetic diversity of the natural population of R. soongorica increased with the decreasing of the content of soil organic matters, water, total N and total P in soil. The paper concluded that the microenvironment ecological factors played an important role in the adaptive evolution of R. soongorica population. 相似文献
6.
利用尿液中的雌二醇、孕酮含量监测雌性川金丝猴的月经周期和妊娠 总被引:8,自引:2,他引:8
During two consecutive mating seasons from August 2001 to December 2002, we observed the sexual behavior of Sichuan golden monkeys in the Chengdu Zoo and the Shanghai Wild Animal Park. We collected urine samples from females in the early morning. We also measured urinary estradiol and progesterone levels using radioimmunoassay. Based on the estradiol concentration during the menstrual cycle, we discovered that the length of the menstrual cycle was 286.33 1.67 days. The length of pregnancy was about 200 days. The level of estradiol after impregnation was significantly different with the level during the ,same period in the non-receptive part of the cycle. Thus we could diagnose early pregnancy in female Sichuan golden monkeys by checking their urinary estradiol level . 相似文献
7.
The genus Papulaspora was named by Preuss in 1851 based on the characters of “bulbils” (papulospores) and interpreted by Hotson (1912,1917) as consisting of sterile mycelia with various kinds of “bulbils”. 25 Papulaspora species were described by Hotson in detail (1912, 1917), among them 10 species were acknowledged by Weresub & LeClair (1971) and 20 species were recorded in the Dictionary of the Fungi (2003). The ecology of Papulaspora species is not well known, most species were isolated from dung, decaying plant material or soil. 相似文献
8.
EFFECTS OF HUMAN ACTIVITIES ON STRUCTURE AND COMPOSITION OF WOODY SPECIES OF THE NOKREK BIOSPHERE RESERVE OF MEGHALAYA,NORTHEAST INDIA
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Aims Our study was conducted in the Nokrek Biosphere Reserve (NBR) in the Garo hills districts of Meghalaya, Northeast India. Our aim was to assess the effects of human activities on plant diversity,population structure and regeneration.Methods We selected a representative 1.2 hm2 stand in both the core and buffer zones of NBR. Structure and composition were determined by randomly sampling square quadrats, population structure was assessed by determining age structure, and regeneration was assessed by measuring densities of seedling, sapling and adult trees.Important findings More woody species were recorded from the core zone than the buffer zone (87 vs. 81 species), and there were a large number of tropical, temperate, and Sino-Himalayan, Burma-Malaysian and Malayan elements, primitive families and primitive genera. The trees were distributed in three distinct strata,canopy, subcanopy and sapling. Subcanopy and sapling layers had the highest species richness (81% -88% ). Lauraceae and Euphorbiaceae were the dominant families in terms of the number of species, and a large number of families were represented by single species. Most woody species (57 % - 79 % ) were contagiously distributed and had low frequency ( < 20% ). Although stand density was high in the buffer zone, its basal area was low compared to the stand in the core zone. Low similarity and high β-diversity indicate marked differences in species composition of the stands. Shannon diversity index was high in both the stands, while Simpson dominance index was low. The diameter-class distribution for dominant species revealed that the most had a large number of young individuals in their populations. Preponderance of tree seedlings, followed by a steep decline in population density of saplings and adult trees, indicated that the seedling to sapling stage was the most critical in the life cycle of the tree populations. Most species (42 % - 48 % ) had no regeneration,25 % - 35 % had good/fair regeneration, and the rest had poor regeneration or reoccurred as immigrants. 相似文献
9.
Xun-Xun CHU Joshua Dominic Rizak Shang-Chuan YANG Jian-Hong WANG Yuan-Ye MA Xin-Tian HU 《动物学研究》2014,(3)
Within the postpartum period, both mothers and infants are susceptible; but because PPD typically occurs for short durations and has moderate symptoms, there exists challenges in exploring and addressing the underlying cause of the depression. This fact highlights the need for relevant animal models. In the present study, postpartum adult female cynomolgus monkeys(Macaca fascicularis) living in breeding groups were observed for typical depressive behavior. The huddle posture behavior was utilized as an indicator of behavioral depression postpartum(BDP) as it has been established as the core depressive-like behavior in primates. Monkeys were divided into two groups: A BDP group(n=6), which were found to spend more time huddling over the first two weeks postpartum than other individuals that formed a non-depression control group(n=4). The two groups were then further analyzed for locomotive activity, stressful events, hair cortisol levels and for maternal interactive behaviors. No differences were found between the BDP and control groups in locomotive activity, in the frequencies of stressful events experienced and in hair cortisol levels. These findings suggested that the postpartum depression witnessed in the monkeys was not related to external factors other than puerperium period. Interestingly, the BDP monkeys displayed an abnormal maternal relationship consisting of increased infant grooming. Taken together, these findings suggest that the adult female cynomolgus monkeys provide a natural model of behavioral postpartum depression that holds a number of advantages over commonly used rodent systems in PPD modeling. The cynomolgus monkeys have a highly-organized social hierarchy and reproductive characteristics without seasonal restriction—similar to humans—as well as much greater homology to humans than rodents. As such, this model may provide a greater translational efficiency and research platform for systematically investigating the etiology, treatment, prevention of PPD. 相似文献
10.
Genetic diversity level of Cathaya argyrophylla was confirmed by random amplified polymorphic DNA (RAPD) markers. Seventy five samples (individuals), collected from Hunan and Sichuan provinces of China were used in the study. 21 10-mer oligonucleotide primers detected 106 sites, and 34 (32% ) of them were polymor-phic. The level of genetic variation in C. argyrophylla was lower than those of other conifers, and was considered to be associated with the complexity of habitats. The percentages of polymorphic sites (PPS) in the Hunan and Sichuan pop-ulations were 18% and 25% respectively. 7.99% of genetic variation existed between the two populations; this value was higher than the mean value (6.8%) among populations in conifers displayed by allozyme. Some subpopulations of C. argyrophylla were greatly differentiated because of site mutation and genetic drift. The highest value of genetic dif-ference between subpopulations amounted to 16. 23% . In addition, a concept of diversity coefficient(DC), a value us 相似文献