苹果全爪螨在吉尔吉斯与金冠苹果上的实验种群两性生命表

为明确新疆野苹果Malus sieversii吉尔吉斯与栽培苹果Malus domestica金冠对苹果全爪螨Panonychus ulmi生长发育和繁殖的影响, 在室温23±1℃, 相对湿度75%±5%, 光周期16L∶8D条件下, 组建了苹果全爪螨在吉尔吉斯和金冠上的实验种群两性生命表。结果显示： 吉尔吉斯和金冠对苹果全爪螨雌螨寿命、 产卵期及总产卵量等有明显影响、 而对总发育历期、 总产卵前期、 未成熟螨存活率等影响不显著。苹果全爪螨总发育历期在吉尔吉斯（雌12.60 d, 雄11.40 d）和金冠（雌12.54 d, 雄 11.67 d）上无显著差异, 雌成螨寿命在金冠(13.46 d)上显著长于在吉尔吉斯（10.88 d）上(P<0.05)。产卵期在金冠和吉尔吉斯上分别为10.55 d和8.30 d, 达到显著差异水平(P<0.05)。总产卵量在金冠上为34.12粒/雌, 显著高于在吉尔吉斯上（22.48粒/雌）(P<0.05)。苹果全爪螨在吉尔吉斯上内禀增长率(r)、 净增殖率(R₀)、 世代平均周期(T)、 周限增长率(λ)分别为0.1354, 11.96, 18.33和1.1450, 而在金冠上分别为0.1489, 17.39, 19.18和1.1606。由种群动态参数可知, 苹果全爪螨在金冠上种群数量增长快于在吉尔吉斯上。研究结果有助于深入了解该螨在新疆野苹果与栽培苹果上种群动态, 并为苹果抗螨性育种及害螨综合治理提供理论依据。     

胡瓜钝绥螨对苹果全爪螨的生物防治效果

以生命表参数及天敌在室内和田间的应用效果来评价胡瓜钝绥螨对苹果全爪螨的控制效果.结果表明:胡瓜钝绥螨取食苹果全爪螨,能够完成发育历期并产卵,在(25±1)℃条件下一个世代仅需9.54d;其雌螨产卵期(24.85d)和寿命(38.52d)都比猎物的产卵期(15.93d)和寿命(34.79d)长,雌螨的平均产卵量仅为苹果全爪螨的56.1%;苹果全爪螨净增殖率(R0)和内禀增长率(rm)分别比胡瓜钝绥螨高103.9%和13.2%.室内释放情况下,无论益害比是1:30还是1:150,释放20d后防治效果均可达95%以上;在苹果示范园释放胡瓜钝绥螨,60d后防治效果达91.73%,比化防园高23.77%.表明胡瓜钝绥螨具有优良天敌的重要特征,在每叶苹果全爪螨低于2头时,果园释放胡瓜钝绥螨能有效控制苹果全爪螨的种群增长.     

苹果全爪螨的空间分布格局及时序动态

苹果全爪螨是影响我国苹果生产的重要害虫之一.为明确其在苹果树冠上的时空格局,在2007年5-11月整个生长季节,采用不同方位、不同层面随机取样的方法调查害螨数量.应用聚集度指标法和Iwao回归测度法分析苹果全爪螨在苹果树上的分布型及其变化动态.结果表明:苹果全爪螨在苹果树冠整体范围内前期和中期符合负二项分布,呈聚集型,基本成分为个体群,且个体间相互吸引.聚集强度随种群密度的消长而波动,表现出高密度、低聚块及低密度、高聚块的规律,并且在树冠的不同方位和不同层面上存在一定差异:个体群的聚块性南部最高,西部最低;树冠中、下层高于上层,内层高于外层.     

巴氏钝绥螨对柑桔全爪螨的捕食效能

本文研究了巴氏钝绥螨Amblyseius barkeri的雌成螨、雄成螨、若螨在实验条件下对柑桔全爪螨的捕食效能。结果表明：5个实验温度条件下（16、20、24、28和32℃,RH85％）,利用椭圆食粉螨饲养的巴氏钝绥螨Panonychus citri对柑桔全爪螨均有较强的捕食能力;巴氏钝绥螨对柑桔全爪螨的功能反应均属于Holling Ⅱ型。在实验温度范围内,各螨态对柑桔全爪螨的控制能力（α／Th值）随温度升高而增大,在28℃时达到峰值;同一温度条件下,雌成螨的捕食能力最大,若螨其次,雄成螨的捕食能力最弱;在猎物密度固定时,由于巴氏钝绥螨个体之间存在相互竞争和相互干扰作用,随着捕食者密度的提高,捕食者平均捕食量逐渐减少。巴氏钝绥螨对各螨态柑桔全爪螨的取食有选择性,柑桔全爪螨的幼若螨是巴氏钝绥螨的嗜好虫态。     

柑桔全爪螨自然种群动态的模拟模型

本文运用时间序列分析方法对上海市长兴岛前卫农场柑桔园内柑桔全爪螨及其天敌江原钝绥螨的种群动态进行分析和模拟,分别建立了关于柑桔全爪螨及其天敌种群数量动态的作用,预测柑桔全爪螨种群数量的变化趋势,模拟效果良好,对田间防治具有一定的参考价值。     

纽氏钝绥螨、尼氏钝绥螨及其猎物—桔全爪螨生态学特性的比较研究

本文从天敌与猎物的种群内禀增长力,天敌对猎物不同密度的功能反应及数值反应三个方面来评价和比较纽氏钝绥螨、尼氏钝绥螨时其猎物——枯全爪螨的控制作用。在五种温度下,两种捕食螨的种群内禀增长力都大于桔全爪螨。它们对猎物的功能反应属HollingⅡ型。尼氏钝绥螨的捕食量大于纽氏钝绥螨,在25℃时两种捕食螨捕食量最大,应用Rogers的模型能较好地对试验结果进行模拟。尼氏钝绥螨对桔全爪不同虫态的取食不存在选择效应,纽氏钝绥螨则嗜食若螨和幼螨。两种捕食螨对桔全爪螨的数值反应表明,仅供给桔全爪螨雌成螨作为食物,对两种捕食螨都不利,尤其对尼氏钝绥螨更为明显。综上所述,两种捕食螨能比较有效地控制桔全爪螨种群,当猎物密度较高时,尼氏钝绥螨控制效果优于纽氏钝绥螨,但纽氏钝绥螨控制效果优于纽氏钝绥螨,但纽氏钝绥螨田间种群数量比尼氏钝绥螨稳定。柑桔园中存在其它补充食物时对这两种捕食敌有利。     

竹缺爪螨生态学初步研究

本报道严重危害毛竹生长和害螨－－竹缺爪螨在不同温度下生长,发育历期以及在竹林间种群动态。结果表明：在20－35℃范围内随着温度升高其发育历期缩短,温度与发育历期呈直线回归关系：Y全代＝651573-1.6250X（=-0.98);光照是影响竹缺爪螨的卵,幼螨存活及成螨产卵量的重要因素。在竹林间,毛竹换叶,降雨量,天敌数量是影响竹缺爪螨种群消长的和重要因素,最后提出综合防治的措施。     

桔全爪螨与柑桔相互作用的研究

研究了不同柑桔品种对桔全爪螨Ｐａｎｏｎｙｃｈｕｓｃｉｔｒｉ（ＭｃＧ）种群的影响,桔全爪螨危害对柑桔生理的影响以及柑桔叶片受受后对桔全爪螨种群的反馈作用,结果表明：供试的１０个柑桔品种对桔全爪螨种群生长发育,繁殖时明显的影响,品种间存在感螨性差异。     

柑橘全爪螨种群空间格局的地学统计学分析

应用地学统计学方法分析了柑橘园主要害螨柑橘全爪螨Panonychus citri（McGregor）种群的空间格局及其动态。结果表明,柑橘全爪螨种群具有空间相关性,变程介于1．10～21．0m,其半变异函数主要符合高斯模型,表现为聚集分布,其中3月、8月和9月的聚集强度较大;种群空间格局动态显示,4月、10月为该种群的两个发生高峰期,柑橘全爪螨种群数量快速上升扩散。地学统计学方法能够应用于柑橘全爪螨种群的空间格局分析,并有助于对该害螨进行发生预测与控制处理。     

苹果全爪螨实验种群的密度效应研究

研究了苹果全爪螨实验种群的密度效应。实验结果表明：二斑叶螨卵期不存在密度效应;幼、若螨期间存在密度效应,幼、若螨密度与其成活率明显相关,幼、若螨初始密度的增加导致死亡率增加,并且当代性比向偏雌性方向发展,而子代性比向偏雄性方向发展;不同幼、若螨密度和成螨密度对成螨产卵量均有极显著差异。苹果叶片上螨口密度大于2．5～3．5头／cm^2时,扩散量明显增加。     

A host shift from wild blue cohosh to cultivated potato by the phytophagous ladybird beetle, Epilachna yasutomii (Coleoptera, Coccinellidae)

Life history traits of the phytophagous ladybird beetle Epilachna yasutomii were compared between a nonpest population feeding on wild blue cohosh and a pest population feeding on cultivated solanaceous crops, mainly potato. Newly emerged adults of the nonpest population entered diapause early in midsummer when blue cohosh withered, while adults of the pest population were found in tomato and eggplant fields until late autumn. The pest population had larger females, a higher population growth rate, a shorter larval developmental period, and reduced longevity of overwintered females, compared with the nonpest population. ANOVA indicated that all these life history traits were influenced by the food plant, and that the number of eggs laid per female and the longevity of overwintered females were also affected by the population type. These findings suggest that the life history pattern of E. yasutomii changed to high fecundity with a short life span from low fecundity with a long life span as a result of the host shift from wild blue cohosh to cultivated solanaceous crops. Received: May 22, 1998 / Accepted: January 13, 1999     

武夷山米槠种群结构及谱分析

在武夷山自然保护区对米槠种群数量动态进行了系统研究,编制了静态生命表,分析了存活曲线和死亡曲线,同时应用谱分析方法分析种群数量的动态变化。结果表明,武夷山自然保护区米槠种群基本属于进展型或稳定型,幼龄级个体多,中老龄级个体少。不同海拔的种群密度存在差异,其中C种群密度最大;静态生命表显示,种群在Ⅰ、Ⅱ径级时死亡率较高,随着年龄增加,死亡率逐渐降低,但到了Ⅳ、Ⅴ径级,由于生理衰老死亡率又上升;种群期望寿命在Ⅰ、Ⅱ径级较高,随着年龄增加,期望寿命逐渐下降;不同海拔的米槠种群的存活曲线均接近于Deevey Ⅲ 型。米槠种群自然更新过程存在明显的周期。     

Life‐history strategy varies with the strength of competition in a food‐limited ungulate population

Fluctuating population density in stochastic environments can contribute to maintain life‐history variation within populations via density‐dependent selection. We used individual‐based data from a population of Soay sheep to examine variation in life‐history strategies at high and low population density. We incorporated life‐history trade‐offs among survival, reproduction and body mass growth into structured population models and found support for the prediction that different life‐history strategies are optimal at low and high population densities. Shorter generation times and lower asymptotic body mass were selected for in high‐density environments even though heavier individuals had higher probabilities to survive and reproduce. In contrast, greater asymptotic body mass and longer generation times were optimal at low population density. If populations fluctuate between high density when resources are scarce, and low densities when they are abundant, the variation in density will generate fluctuating selection for different life‐history strategies, that could act to maintain life‐history variation.     

Modelling life history strategies with capture–recapture data: Evolutionary demography of the water skink Eulamprus tympanum

Matrix population models, elasticity analysis and loop analysis can potentially provide powerful techniques for the analysis of life histories. Data from a capture–recapture study on a population of southern highland water skinks (Eulamprus tympanum) were used to construct a matrix population model. Errors in elasticities were calculated by using the parametric bootstrap technique. Elasticity and loop analyses were then conducted to identify the life history stages most important to fitness. The same techniques were used to investigate the relative importance of fast versus slow growth, and rapid versus delayed reproduction. Mature water skinks were long‐lived, but there was high immature mortality. The most sensitive life history stage was the subadult stage. It is suggested that life history evolution in E. tympanum may be strongly affected by predation, particularly by birds. Because our population declined over the study, slow growth and delayed reproduction were the optimal life history strategies over this period. Although the techniques of evolutionary demography provide a powerful approach for the analysis of life histories, there are formidable logistical obstacles in gathering enough high‐quality data for robust estimates of the critical parameters.     

准噶尔盆地东南缘梭梭种群结构与动态研究

通过样地调查和数据统计分析,对准噶尔盆地东南缘梭梭种群现状绘制径级结构图,编制生命表、分析存活曲线、死亡率曲线和寿命期望等参数,并运用时间序列模型预测种群数量动态.结果表明:种群整体结构属于增长型,但梭梭种群幼苗个体少,Ⅰ、Ⅱ龄级个体数目少于Ⅲ龄级的个体数目.存活曲线基本接近DeeveyⅢ型,种群偏离典型存活曲线的程度与幼苗缺乏有关;环境因素和人为干扰的影响,梭梭在Ⅲ～V龄级死亡率较高,种群在第Ⅳ级出现死亡高峰,且只有少量幼年个体能进入成年阶段,个体平均生存能力的期望在第Ⅳ级最大;时间序列分析表明,在未来第Ⅱ、Ⅳ、Ⅵ、Ⅷ龄级的个体会呈现老龄个体增加的趋势,种群稳定性长期维持困难.适当的人工辅助恢复和现有植株及生境的保护是保持梭梭种群自然更新和种群恢复的关键.     

木荷天然种群生命表分析

以种群生命表及生存分析理论为基础,编制的木荷种群特定时间生命表,绘制死亡密度函数曲线、危险率函数曲线及生存曲线,分析种群动态趋势。结果表明,木荷种群有3个死亡高峰,个体平均生存能力的期望在第3龄级最大;存活曲线属于典型的Deevey-Ⅲ型,种群前期存活数随龄级急剧下降,只有11%的幼株能进入第2龄级,而后期存活值波动不大。     

小陇山国家级自然保护区华山松种群更新动态分析

以种群生命表及生存分析理论为基础,将林木依胸径大小分级,以林木径级结构代替年龄结构,采用分段匀滑技术编制小陇山国家级自然保护区华山松种群静态生命表,对其种群年龄结构、死亡率曲线、损失度曲线、存活曲线、生存函数曲线及其幼苗的更新动态、死亡率和原因进行分析。结果表明:该种群属于增长型,表现出前期增长,中期稳定,后期衰退的特点;该种群的整个生命过程,显示了三次死亡高峰,其中幼苗死亡率较高,以后的死亡率低而平缓,符合种群的自然动态规律,也指出"天保工程"实施的意义和效果;该研究指示了华山松的动态以及种群的变化趋势,对保护区已经实施的生态监测和森林保护有着十分重要的意义。     

Effects of the population density on growth of SD-JCL rats (author's transl)]

The effects of the population density on growth and life span of 21 to 26 months in SD-JCL-rats were investigated. The mean life spans of males and females were 23 and 24 months, respectively. The population density had no definite influence on increase in body weight of females, whereas a most accelerated growth of males was seen with 2 rats per cage. The total amounts of food intake of each animal throughout its life were about 15 and 11 kg for males and females, respectively, and those of water intake were about twice the food. No correlation was observed between the population density and the weights of the liver, kidney, heart and femur, though mals reared at 5 animals per cage had lightest adrenals among all the animals.     

Inbreeding depression in perennial Lychnis viscaria (Caryophyllaceae): effects of population mating history and nutrient availability

We studied inbreeding depression in a perennial plant, Lychnis viscaria, in three populations differing in their inbreeding history and population size by measuring several traits at two nutrient levels over the plant's life cycle. The observed levels of inbreeding depression (cumulative inbreeding depression, from -0.057 to 0.629) were high for a plant with a mixed mating system. As expected, the population with a low level of isozyme variation expressed the least inbreeding depression for seed germination. Highest inbreeding depression for germination was found in the largest and genetically most variable population. No clear differences between populations in expression of inbreeding depression in the later life stages were found. The population level inbreeding depression varied with the nutrient conditions and among populations and life stages, but we found no evidence that inbreeding depression increased with lower nutrient availability. These results emphasize the importance of measuring inbreeding depression under several environmental conditions and over life stages.     

Life span correlates with population dynamics in perennial herbaceous plants

Survival and fecundity are basic components of demography and therefore have a strong influence on population dynamics. These two key parameters and their relationship are crucial to understand the evolution of life histories. It remains, however, to be empirically established how life span, fecundity, and population dynamics are linked in different organism groups. We conducted a comparative study based on demographic data sets of 55 populations of 23 perennial herbs for which structured demographic models and among-year natural variation in demographic attributes were available. Life span (from 4 to 128 yr old), estimated by using an algorithm, was inversely correlated with the deviance of the population growth rate from equilibrium as well as with among-year population fluctuations. Temporal variability was greater for short-lived species than for the long-lived ones because fecundity was more variable than survival and relatively more important for population dynamics for the short-lived species. The relationship between life span and population stability suggests that selection for longevity may have played an important role in the life history evolution of plants because of its ability to buffer temporal fluctuations in population size.