Population frequencies of alternative male phenotypes in tree lizards: geographic variation and common-garden rearing studies

Tree lizards (Urosaurus ornatus) vary in throat fan (dewlap) color. Earlier, we described five dewlap types (Orange, Orange-Blue, Yellow, Yellow-Blue, and Blue), and reported that only males had blue in the dewlap and that presence or absence of a discrete blue patch was correlated with male alternative reproductive phenotypes in a central Arizona population. Here, with a modified scheme characterizing two dewlap elements, background color (orange, yellow, blue) and blue patch occurrence, we assessed: (1) sexual, annual, and geographic variation in the frequencies of dewlap elements; (2) simple habitat correlates; and (3) the effects of laboratory rearing regime on dewlap type. Within a population, frequencies of males and females expressing orange or yellow backgrounds did not differ, suggesting that control of background is similar in the sexes. Within several populations, frequencies of the dewlap elements did not differ across years (and probably generations), indicating that phenotype frequencies are relatively stable. Among five populations frequencies of background colors varied, as did frequencies of male types (blue patch present or absent). Dewlap frequencies did not correlate with habitat (boulders or mesquite trees), although few populations were sampled. In male and female offspring reared from eggs to sexual maturity in a common-garden laboratory study, background color frequencies in both sexes and blue patch frequencies in males differed among offspring from different populations. Offspring frequencies matched respective parental population frequencies. Results suggest that among-population variation in frequencies of the two dewlap elements are mediated by differences in genetics, in maternal effects, or both. Thus, differences in male behavior functionally linked to the blue patch also may be controlled by genetic or maternal effects. Received: 17 January 1997 / Accepted after revision: 30 August 1997     

重视生态策略在建筑设计中的运用

建筑既作用于生态环境，也作用于人类，它始终持续地影响着周围的环境和使用者的生活，特别是对于我国高速发展的城市来说，其影响更是巨大。生态建筑将成为21世纪建筑设计的主流。建筑与可持续发展的三个重要方面(环境保护、经济发展和社会进步)密切相关，生态建筑应是可持续发展的一个组成部分。文章针对我国生态环境与建筑设计中存在的主要问题，提出在建筑设计中要注重生态策略的运用，推动生态建筑设计要依靠全社会生态意识的提高，增强人与自然环境的沟通，完善生态建筑设计的法律规范。     

湖南省南瓜和西葫芦的产业现状、问题及发展战略

就湖南省农业产业化结构的调整,正确认识南瓜、西葫芦产业化的优势,现根据湖南农业气候状况及南瓜、西葫芦生产现状,找出南瓜、西葫芦生产中存在的问题,提出南瓜、西葫芦产业竞争力的科学发展战略.表1,参8.     

解决农业高职院校负债融资问题的对策

随着农业高等职业教育的发展,大部分的农业高职院校都普遍地采用了负债融资这一形式来维持运转和发展.然而,如果到期没有足够现金流偿债,会使高校陷入财政危机而影响正常教学秩序,形成负债融资风险.本文从改善农业高职院校的负债融资环境,拓展农业高职院校的负债融资渠道,加强农业高职院校的负债融资管理三方面对农业高职院校的负债融资问题进行研究,提出了解决的对策.     

Evolution of male dimorphic allometry in a population of the Japanese horned beetle <Emphasis Type="Italic">Trypoxylus dichotomus septentrionalis</Emphasis>

I conducted a detailed morphological analysis of the Japanese horned beetle Trypoxylus dichotomus septentrionalis to clarify the allometric relationship between horn length and body size and examined its mating success and reproductive behaviour in the field. The relationship between horn and body size was not discontinuous at the switch point body size, but the slope of the linear relationship changed at the switch point. Shape of the allometric relationship was initially steep and became flatten around the switch point in both linear and log scales; that is, minor males showed a positive relationship and major males showed a negative one. Major males gained more mating success than minor males. Within major males, individuals with larger horn or body size had higher mating success than individuals with smaller ones. Within minor males there were no differences in horn and body size between mated and unmated individuals. Although sneak-like behaviours were exhibited by both morphs, it is likely that these behaviours rarely lead to direct benefit. These results suggest that dimorphic allometry of T. dichotomus is consistent with the hypothesis of a continuous reaction norm that meets a ceiling, which restrains further allometric growth.     

Alternative reproductive tactics and male-dimorphism in the horned beetle Onthophagus acuminatus (Coleoptera: Scarabaeidae)

Adult dung beetles (Onthophagus acuminatus) exhibit continuous variation in body size resulting from differential nutritional conditions experienced during larval development. Males of this species have a pair of horns that protrude from the base of the head, and the lengths of these horns are bimodally distributed in natural populations. Males growing larger than a threshold body size develop long horns, and males that do not achieve this size grow only rudimentary horns or no horns at all. Previous studies of other horned beetle species have shown that horned and hornless males often have different types of reproductive behavior. Here I describe the mating behaviors of the two male morphs of O. acuminatus during encounters with females. Females excavate tunnels beneath dung, where they feed, mate and provision eggs. Large, horned males were found to guard entrances to tunnels containing females. These males fought with all other males that attempted to enter these tunnels. In contrast, small, hornless males encountered females by sneaking into tunnels guarded by other males. In many instances, this was accomplished by digging new tunnels that intercepted the guarded tunnels below ground. Side-tunneling behavior allowed sneaking males to enter tunnels beneath the guarding male, and mate with females undetected. Both overall body size and relative horn length significantly affected the outcome of fights over tunnel ownership. These results suggest that alternative reproductive tactics may favor divergence in male horn morphology, with long horns favored in males large enough to guard tunnels, and hornlessness favored in smaller males that adopt the “sneaking” behavioral alternative. Received: 12 October 1996 / Accepted after revision: 8 August 1997     

南岳自然保护区兽类资源考察报告

南岳自然保护区野生兽类动物资源丰富,共有33种,包括7目16科,属东洋界的25种,占75.8 %,属古北界的7种,占24.2 %.区内珍稀动物种类多,有大灵猫、小灵猫、野猪、穿山甲、林麝、獐等6种国家二级保护动物,12种湖南省重点保护动物.区内兽类动物由于偷猎乱捕,有些种类如华南虎、云豹已灭绝,有些动物种类已濒临灭绝,采取措施保护已刻不容缓.     

Sperm traits of the quacking frog, Crinia georgiana: intra- and interpopulation variation in a species with a high risk of sperm competition

Sperm traits often show extreme variation both between and within species. Between-species variation may often be interpreted in the context of a sperm competition theory, but within-species variation has remained unexplained. Previous studies on intraspecific variation in sperm traits have focused on a limited set of variables and may have failed to explain observed variation because of potential trade-offs between different sperm traits. We report on variation in number, size, motility and longevity of sperm in the frog Crinia georgiana, a species where sperm competition is common. We found intrapopulation variation in sperm size and motility and interpopulation variation in relative sperm number and size. When we combined relative sperm number and size into one variable, and motility and longevity into another, we found significant interpopulation variation in these variables as well. We also detected considerable intra- and significant interpopulation variation in cumulative sperm quality, a combination of all four sperm traits. Furthermore, a significant effect of the interaction between population origin and male size on sperm characteristics indicated interpopulation variation in the strength of selection acting on sperm traits of males adopting different mating strategies. We discuss heterogeneity in the reproductive environment, a complex genetic background in the determination of sperm characteristics and varying levels of developmental noise as potential contributors to the observed variation in sperm traits.     

上市公司会计数字游戏的剖析

本文从会计数字游戏产生的根源着手，分析了上市公司会计数字游戏滋生的内、外部条件及诱因，进而分析如何才能够减少会计数字游戏．     

揭阳市生态农业发展的思路

分析了揭阳市生态农业发展的现状、有利条件及制约囚素，总结了对该市发展生态农业有积极影响的揭东县塔西种养场生态种养模式，最后提出了该市生态农业的发展模式、发展思路和对策。