Search Results

You are looking at 1 - 10 of 29 items for

  • Author or Editor: Xin Lu x
  • Nach Ebene eingrenzen: All x
Clear All
Authors: Xin Lu and Wen Bo Liao

Abstract

In animals, body size is a prominent trait that generally positively affects ecological and reproductive success. Through field observations and experiments, we investigated the effects of two mechanisms of sexual selection on large male mating advantage in the Andrew's toad, Bufo andrewsi, a species widely distributed in western China. We observed a large male mating advantage in the field. Field data were corroborated by experiments in which large males mated more frequently than smaller males. However, in female preference tests, in which females could choose freely between two males differing in body size, choosing females showed no size preference while many females did not exert mate choice at all. We suggest that the large male mating advantage observed in the field and laboratory is caused by competition among males rather than by female choice.

In: Behaviour
Authors: Wen Bo Liao and Xin Lu

Abstract

Elevation that results in changes in climate, duration of breeding season and food resource has long been considered a major influence on the evolution of life-history traits in amphibians. The present study examined differences in reproductive output (clutch size and egg size) of the Omei Treefrog (Rhacophorus omeimontis) at two elevations (1000 m and 1700 m above sea level) in Baoxing County, western China. Within each population, female attributes (size and age) were responsible for much of the reproductive output variation in that larger or older females produced larger clutches of smaller eggs. Clutch size and egg size showed a significantly negative correlation, which was indicative of a trade-off between the two parameters. The high-elevation females were significantly larger than the low-elevation counterparts. After accounting for interpopulational difference in body size, clutch size, egg size and clutch volume differed significantly between the populations. For the high-elevation population relatively smaller clutches tended to be associated with larger eggs. Our findings suggest that females produce smaller clutches relative to body size and larger eggs in the high-elevation population to ensure that each egg is adequately provisioned in the face of cold climate and short duration of development.

In: Animal Biology
Authors: Xin Lu and Wen Bo Liao

Abstract

The age and body size of Amolops mantzorum between two populations distributed in western China were estimated using skeletochronology. The age at sexual mature of individuals was be estimated 2 yrs old in males for both populations while females reached sexual maturity at 2 yrs old at the low-altitude site and 3 yrs old at the high-altitude site. The oldest males and females from the high-altitude site were 7 yrs and 10 yrs old while longevity of males reached 6 yrs and 7 yrs in females at the low-altitude site. Average age between males and females differed significantly at the high-altitude site, but it did no differ significantly at the low-altitude site. For both sexes, average age did not differ significantly between the populations. On average, adult females had significantly larger body sizes than adult males for both populations. Sexual size dimorphism from the low-altitude site and the high-altitude site was 0.280 and 0.282, respectively. Body size between the populations differed significantly within each sex. Positive correlations were found between age and body size for both sexes within each site. The growth coefficient did not differ significantly within a population both sexes or in a sex between the populations. Our findings suggest that inter-population difference in body size of the frogs seems to be related to longevity of individuals, ambient temperature and construction of dams for electricity.

In: Animal Biology
Authors: Xin Lu and Xiaoyan Ma

Abstract

The annual cycle of reproductive organs in a wild population of a Tibetan frog, Nanorana parkeri, was studied. For females we used the pigmentation and size of the ovarian follicles to designate the reproductive conditions. Males were analyzed according to their spermatogenic stages using histological sections of their testes. The results showed that each sex had a seasonal reproductive cycle. However, females reproduced biennially or more, while males bred annually. We presumed that the sexual differences in reproductive investment contributed to the annual reproductive cycle difference between the sexes of N. parkeri. Moreover, this species did not have the post-breeding resting period, which was confirmed by the fact of reinitiation of spermatogenesis shortly after breeding.

In: Animal Biology
Authors: Xin Lu and Xiaoyan Ma

Abstract

The number of lines of arrested growth (LAGs) in diaphyseal cross-sections of phalanges or femora was used to assess individual age and growth of 612 Nanorana parkeri, including 363 males, 143 females, 70 juveniles, and 36 tadpoles, in a population from central Tibet, China. The oldest immature frogs had an age of 6 years; both the youngest sexually mature males and females were 3 years old. However, the majority of individuals bred for the first time at 5 years in males and 6 years in females. Females had greater average age (6.27 years) and lifespan (11 years) than males (5.72 and 10 years). At the population level, females, on average, were significantly larger in body length (40.3 mm) than males (37.0 mm). However, the significant size difference only occurred when both sexes were over 6 years old, at which most frogs attained maturity. Growth curve and growth rate estimated for each sex based on a von Bertalanffy model showed that females had a larger asymptotic size (54.2 mm) but smaller growth coefficient k (0.16) than males (40.0 mm, 0.37), and that females had greater growth rate than males in all age classes, except at metamorphosis. According to these results, we concluded that the sexual difference of growth between pre- and post-maturation periods contributed to the age-specific sexual size dimorphism of N. parkeri.

In: Amphibia-Reptilia
Authors: Xueyi Lu and Peilin Li
Editor: Xin Ru
With a population of now over 1.3 billion people, any change in China’s social environment is bound to have dramatic impact. The China Society Yearbook (2006) provides analysis of and commentary on social issues in contemporary China, broken down into chapters on different aspects of China’s social development, including change in social structure, population growth, employment, standard of living and education. The Yearbook provides detailed insight into the vast changes in Chinese society since the foundation of the People’s Republic of China and the Mao period, the effects of the country’s ongoing reform and liberalization process on its social makeup, the main aims of the 11th Five-Year Plan, and the daunting problems that China’s economic and social planners face as their country’s economy adapts to a free market system, while raising the standard of living and generating employment for its burgeoning work force.

Also included are in-depth comparisons of the country’s different social groups, including its 120 million migrant workers, as well as descriptions of social development in different areas of China’s vast hinterland, where economic development varies greatly from that of the economically and socially upwardly-mobile coastal crescent. Compiled and edited by top sociologists of the Chinese Academy of Social Sciences (CASS), this collection of current research and analysis represents some of the most pioneering and influential articles by social science scholars in the People’s Republic of China.
Editors: Xin Ru, Xueyi Lu, and Peilin Li
The China Society Yearbook, Volume 5 continues the ten-year tradition of presenting precise and venerable academic principles by compiling the findings of the Chinese Academy of Social Sciences’ subject research group for the “Analysis and Forecast of the Social Situation”. The focus of the research group centered around three themes for 2009-2010. First, the steps China is taking to lead the country away from the shadow of the financial crisis and begin a new stage of growth. The second focus was how to organize this new growth stage. China's development relies on upgrading the industrial structures, transforming the social and economic structures, and stimulating domestic consumption demand. Finally, the group addressed China’s policy of an overall restructuring that focuses on major societal issues such as employment, division of income, education, health and medical systems, social security, the urban-rural administration system, public institution administration, and the community and social organizational reform.

Written by contributors from professional research and survey organizations, universities, and related governmental sections, The China Society Yearbook, Volume 5 provides an excellent resource for those interested in current societal changes in China.
Editors: Xin Ru, Xueyi Lu, and Peilin Li
The year 2008 marked a historical turning point for China, with the 30th anniversary of the launch of China’s opening and reform policy, and the Olympic Games in Beijing. On a negative note, the year was also marked by the Sichuan earthquake and the subprime mortgage crisis in the USA. China maintained a growth rate of 10% from 2003 to 2007, and began to adjust its industrial structures, shift development modes, and reform the urban-rural duality. China also increased its investment in employment, education, healthcare, social security, and public service sectors, especially in rural areas. The international economic crisis has however dragged down the international economic situation, in response to which the Chinese government is aiming to invest RMB 4 trillion over the next two years to confront this major challenge. China’s economic and social development situation in 2009 will have major significance in the drafting of future economic policy.
Editors: Xin Ru, Xueyi Lu, and Peilin Li
The 2007 volume of The China Society Yearbook, the second volume in the annual China Society Blue Book series to be translated into English, contains important facts and analysis from Chinese scholars on a wide array of issues in China. With over 1.3 billion people and continuous economic growth, Chinese society is experiencing changes on an unprecedented scale. Issues explored in this volume include the progress and goals of the Eleventh Five-Year Plan, China’s rural-to-urban migration, changes in the labor force, labor relations, and consumption habits, assessments of health care and education, analysis of China’s demographic changes, and reports on China’s security, social psychology, and living standards. Along with analysis, this volume offers recommendations and insight into the daunting issues and opportunities facing China as it moves towards a free-market system.