随机配对种群的两性模型的动力学性态

基于Kendall-Goodman模型，提出了一个两性具有不同生理性态的随机配对的两性模型．如果不考虑密度制约因素，那么模型存在一个全局渐近稳定的指数解；如果考虑密度制约因素，对于给定的一个出生函数，得到了唯一正平衡态存在及全局稳定的充要条件．结论表明，无论是否考虑密度制约因素，种群的性比总是稳定的．     

棉蚜田间种群特定死亡率分析

棉蚜田间种群特定死亡率分析戈峰丁岩钦（中国科学院动物研究所,北京１０００８０）ＡｎａｌｙｓｉｓｏｆｔｈｅＴｉｍｅ┐ｓｐｅｃｉｆｉｃＭｏｒｔａｌｉｔｙｏｆＣｏｔｔｏｎＡｐｈｉｄ（Ａｐｈｉｓｇｏｓｓｙｐü）Ｐｏｐｕｌａｔｉｏｎ．ＧｅＦｅｎｇ,ＤｉｎｇＹａ...     

植物种群的性比

总结了植物种群性比的最新研究成果,阐明了自然界植物不同性别的个体间的差异、影响植物种群性比的因素和有关种群性比变化的机理,论述了种群性比变化研究的理论和实践意义.     

运用年龄-龄期两性生命表模拟昆虫种群动态及其在害虫治理中的应用

计算机模拟昆虫的种群数量动态变化对于昆虫种群预测和害虫治理十分重要。本文介绍以年龄-龄期两性生命表(age-stage, two-sex life table)为基础,利用计算机模拟预测昆虫的种群动态、种群捕食、寄生和取食的波动、害虫防治时机以及模拟的变异性。利用年龄-龄期两性生命表软件(程式)TWOSEX-MSChart与捕食率软件CONSUME-MSChart分析生命表与捕食率数据,再将分析结果用模拟软件TIMING-MSChart模拟预测种群增长过程中龄期结构以及捕食能力、寄生能力和取食能力的变化。依据种群动态可以预测害虫危害、天敌捕食、寄生蜂寄生能力,再用这些数据确定杀虫剂的施药时机和施药次数,预测生物防治中天敌释放的适当时机、释放数量和释放次数等;同时还可以依据生命表的变异性,利用自我重复取样(bootstrap)技术得到的2.5和97.5百分位(percentiles)或其他百分位的生命表预测种群增长的不确定性。借助基于两性生命表理论的计算机模拟可以预测害虫种群增长以及化学防治和生物防治的最佳时期,以达到经济有效的害虫综合治理,并为农业可持续性提供理论与技术支撑。     

网湖似刺鳊Ju种群生长和死亡率研究

本文根据６６９尾标本,研究长江中游网湖小型经济鱼类似刺鳊Ｊｕ的种群生长和死亡率,从理论推导证明,鱼类的生长拐点与其临界年龄是一致的,并据以对网湖似刺鳊Ｊｕ等小型经济鱼类的合理渔业对策问题进行了初步分析讨论。     

陕西凤县驯养林麝的种群动态、性比和年龄结构

林麝是濒危资源动物,林麝驯养是保育濒危林麝资源及可持续利用麝香的有效方式。基于对2001至2012年间的陕西凤县林麝驯养的监测和调查,分析了其种群动态、性比和年龄结构。结果表明,陕西凤县的林麝驯养在近10余年获得了快速发展,全县共有150余个麝场,麝场数呈指数式增长,增长率达27.33%,但其平均驯养规模无明显增长,平均存栏种群仅为16.38头。凤县的驯养麝种群总体增长近似指数式增长,增长率达27.22%,目前存栏种群已达3712头。区分性别和年龄,各亚群的增长均呈指数式增长,幼年麝的增长率(30.30%)高于成年麝(27.16%),雄麝的增长率(28.30%)高于雌麝(27.78%)。在2001至2012年间,幼麝种群的雌雄性比((102.64±3.15)%,n=12)和成年麝种群的雌雄性比((100.85±2.585)%,n=10)均显著偏雌(P0.01),但幼麝、成年麝种群间的性比差异不显著(P0.05)。在2005年及2010—2012年间,幼麝(0.5岁龄)占种群的比例为31.91%,亚成体麝(1.5岁龄)占种群的比例为21.11%,成麝(2.5—12.5岁龄)比例为42.72%,老年麝(13.5岁龄及以上)仅占种群的4.26%。合并年龄分析,育龄前个体(幼麝和亚成体麝)的平均比例为53.02%,表明凤县驯养林麝属快速增长种群,其增长潜力较大。在林麝驯养实践中,管理部门可制定准入制度或适当重组现有麝场,促进较大的驯养种群构建,并建立通畅的麝香交易渠道,控制林麝种源的过热交易,以利于林麝驯养种群的性比平衡及可持续的繁育、增长。     

高原鼠兔种群的性比

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.     

基于粪便DNA的马鹿种群数量和性比

为分析黑龙江省完达山林区马鹿种群生存状态,制定科学有效地保护措施,从分子水平研究了种群数量和性比。2006、2007两年冬季跟踪马鹿足迹链,于五泡林场共搜集210份粪便,以成功提取DNA的167份作为分析样本。通过多态性较高的7个微卫星位点进行了基因分型分析,显示167份粪便DNA分属66只个体。基于非损伤性标志重捕法,统计出林场内马鹿数量2a平均47(39—60)只,密度0.302(0.251—0.386)只/km2,与2002年大样方法调查结果相比有减无增。SRY基因性别鉴定显示,种群雌雄性比1.00∶2.00(22♀,44♂),存在较多雄性个体,分析认为偷猎是导致性比失衡的最主要原因。数量的持续下降和性比失衡提示完达山林区马鹿种群数量的恢复需要更好地保护工作。     

网湖似刺鳊鮈种群生长和死亡率研究

本文根据６６９尾标本,研究长江中游网湖小型经济鱼类似刺鳊的种群生长和死亡率,从理论推导证明,鱼类的生长拐点与其临界年龄是一致的,并据以对网湖似刺鳊等小型经济鱼类的合理渔业对策问题进行了初步分析讨论。     

具有吸收状态的昆虫种群矩阵模型的研究

在Vandermeer的昆虫矩阵模型的基础上,提出了具有吸收状态的昆虫种群矩阵模型。并且导出了k步吸收状态与转移状态的矩阵表达式,将有助于昆虫种群动态的研究．     

Population structure leads to male‐biased population sex ratios under environmental sex determination

Spatial structure has been shown to favor female‐biased sex allocation, but current theory fails to explain male biases seen in many taxa, particularly those with environmental sex determination (ESD). We present a theory and accompanying individual‐based simulation model that demonstrates how population structure leads to male‐biased population sex ratios under ESD. Our simulations agree with earlier work showing that the high productivity of female‐producing habitats creates a net influx of sex‐determining alleles into male‐producing habitats, causing larger sex ratio biases, and lower productivity in male‐producing environments (Harts et al. 2014). In contrast to previous findings, we show that male‐biasing habitats disproportionately impact the global sex ratio, resulting in stable male‐biased population sex ratios under ESD. The failure to detect a male bias in earlier work can be attributed to small subpopulation sizes leading to local mate competition, a condition unlikely to be met in most ESD systems. Simulations revealed that consistent male biases are expected over a wide range of population structures, environmental conditions, and genetic architectures of sex determination, with male excesses as large as 30 percent under some conditions. Given the ubiquity of genetic structure in natural populations, we predict that modest, enduring male biased allocation should be common in ESD species, a pattern consistent with reviews of ESD sex ratios.     

Intragenomic conflict produces sex ratio dynamics that favor maternal sex ratio distorters

Maternal sex ratio distorters (MSDs) are selfish elements that enhance their transmission by biasing their host's sex allocation in favor of females. While previous models have predicted that the female‐biased populations resulting from sex ratio distortion can benefit from enhanced productivity, these models neglect Fisherian selection for nuclear suppressors, an unrealistic assumption in most systems. We used individual‐based computer simulation modeling to explore the intragenomic conflict between sex ratio distorters and their suppressors and explored the impacts of these dynamics on population‐level competition between species characterized by MSDs and those lacking them. The conflict between distorters and suppressors was capable of producing large cyclical fluctuations in the population sex ratio and reproductive rate. Despite fitness costs associated with the distorters and suppressors, MSD populations often exhibited enhanced productivity and outcompeted non‐MSD populations in single and multiple‐population competition simulations. Notably, the conflict itself is beneficial to the success of populations, as sex ratio oscillations limit the competitive deficits associated with prolonged periods of male rarity. Although intragenomic conflict has been historically viewed as deleterious to populations, our results suggest that distorter–suppressor conflict can provide population‐level advantages, potentially helping to explain the persistence of sex ratio distorters in a range of taxa.     

黄山松种群结构与动态研究

以“空间代替时间”的方法,以种群径级结构代替年龄结构,采用静态生命表和生存分析的方法,探讨了天柱山国家森林公园黄山松种群结构和动态规律。结果表明,随海拔升高,黄山松种群密度增大,径级分布范围减小,种群存活曲线由Deevey-Ⅱ型之间过渡到Deevey—Ⅰ型,种群由稳定型过渡为增长型。表明由低海拔向高海拔,黄山松种群处于不同的演替和发展阶段。     

Population dynamics of insects associated with Rumex obtusifolius in different habitats

The effect of different habitats on insect communities associated with Rumex obtusifolius was studied in detail. Study sites were selected for their variety of environmental characteristics (vegetation and habitat): shaded woodland, disturbed wasteland and pasture. The results of this study were that insect populations associated with R. obtusifolius responded differently to the different habitats. The observed differences in population dynamics among the insects showed quite clearly their responses to different habitats. There was also a pattern of time partitioning in the exploitation of the host‐plant among the insect species observed. Philaenus spumarius at nymphal stage had a peak density on approximately 20 June, Apion frumentarium and Apion spp. (Apion species other than A. frumentarium) had a peak density on approximately 30 June and Aphis rumicis had a peak density on approximately 28 July. This pattern of shift in time for peak population density (time‐shift) among the insects sharing a common host‐plant may guarantee each insect the opportunity to exploit the plant to a maximum.     

不同松林内马尾松毛虫种群动态的特征

通过对1992-2001年5种不同混交林型的马尾松林内各代幼虫发生量,受害面积和有虫株率的系统调查,研究了各种不同林型的松林对马尾松毛虫种群动态的影响。结果表明,不同树种混交的马尾松林对马尾松毛虫的种群动态有较大的影响。马尾松毛虫在马尾松纯林中发生量多,为害最严重。暴发周期最短;在与杉木等混交的马尾松林中发生次之;而在与阔叶树混交的马尾松林中平均每株虫口数少,发生与危害率及有虫株率均较其它林型小,不易引起松毛虫暴发为害。     

Population dynamics with age- and time-dependent birth and death rates

A continous, deterministic mathematical model is used to predict population distributions by age at any time, given the initial distribution and the variation of birth and death rates with age and time. Solutions are obtained on a computer using a semi-discretization algorithm in which time derivatives in the partial differential equations are replaced by finite-difference expressions. The resulting sets of ordinary differential equations are solved by a predictor-corrector method. Graphical results are shown for some examples.     

Population dynamics: Limits of predictability

Problems related to the complex pattern of ecosystem dynamics are discussed. Examples of studies on the complex population dynamics are considered, including those of plankton populations in a spatially heterogeneous environment and of an agroecosystem invaded by pests resistant to Bt toxins produced by genetically modified insecticidal crops.     

Environmental sex reversal,Trojan sex genes,and sex ratio adjustment: conditions and population consequences

The great diversity of sex determination mechanisms in animals and plants ranges from genetic sex determination (GSD, e.g. mammals, birds, and most dioecious plants) to environmental sex determination (ESD, e.g. many reptiles) and includes a mixture of both, for example when an individual’s genetically determined sex is environmentally reversed during ontogeny (ESR, environmental sex reversal, e.g. many fish and amphibia). ESD and ESR can lead to widely varying and unstable population sex ratios. Populations exposed to conditions such as endocrine‐active substances or temperature shifts may decline over time due to skewed sex ratios, a scenario that may become increasingly relevant with greater anthropogenic interference on watercourses. Continuous exposure of populations to factors causing ESR could lead to the extinction of genetic sex factors and may render a population dependent on the environmental factors that induce the sex change. However, ESR also presents opportunities for population management, especially if the Y or W chromosome is not, or not severely, degenerated. This seems to be the case in many amphibians and fish. Population growth or decline in such species can potentially be controlled through the introduction of so‐called Trojan sex genes carriers, individuals that possess sex chromosomes or genes opposite from what their phenotype predicts. Here, we review the conditions for ESR, its prevalence in natural populations, the resulting physiological and reproductive consequences, and how these may become instrumental for population management.