Phenotypic Diversity of Acer ginnala (Aceraceae) Populations at Different Altitude

In this study, we analyzed the phenotypic variation of Acer ginnala natural populations at different altitude in Qiliyu, investigated the level of phenotypic diversity by using ANOVA analysis, correlation analysis and cluster analysis. The results showed that there were significant differences in phenotypic variation among and within populations. Coefficient of variation (CV) varied from 705% to 3812%. High phonotypic diversity (1.9253) occurred within A.ginnala populations, the mean phenotypic diversity index of populations ranged from 1.9022 to 1.9837. Phenotypic differentiation coefficient (VST) among populations (13.79%) was less than that of within populations (86.21%). The variation within populations comprised a majority of total phenotypic variation. A significant relation had occurred between phenotypic traits and soil factors. Phenotypic diversity index had a very significant correlation with soil total nitrogen (P<0.05), no significant relation with altitude. Five populations gathered into two groups by cluster analysis, which consistent with the geographic distribution of Aginnala in Qiliyu. The traits variations of natural populations at different altitude were affected mainly by micro-environmental heterogeneity of different Aginnala populations. Utilizing of variation within and among populations is important significance for genetic improvement of A.ginnala.     

Variation in Body Shape across Species and Populations in a Radiation of Diaptomid Copepods

Inter and intra-population variation in morphological traits, such as body size and shape, provides important insights into the ecological importance of individual natural populations. The radiation of Diaptomid species (~400 species) has apparently produced little morphological differentiation other than those in secondary sexual characteristics, suggesting sexual, rather than ecological, selection has driven speciation. This evolutionary history suggests that species, and conspecific populations, would be ecologically redundant but recent work found contrasting ecosystem effects among both species and populations. This study provides the first quantification of shape variation among species, populations, and/or sexes (beyond taxonomic illustrations and body size measurements) to gain insight into the ecological differentiation of Diaptomids. Here we quantify the shape of five Diaptomid species (family Diaptomidae) from four populations each, using morphometric landmarks on the prosome, urosome, and antennae. We partition morphological variation among species, populations, and sexes, and test for phenotype-by-environment correlations to reveal possible functional consequences of shape variation. We found that intraspecific variation was 18-35% as large as interspecific variation across all measured traits. Interspecific variation in body size and relative antennae length, the two traits showing significant sexual dimorphism, were correlated with lake size and geographic location suggesting some niche differentiation between species. Observed relationships between intraspecific morphological variation and the environment suggest that divergent selection in contrasting lakes might contribute to shape differences among local populations, but confirming this requires further analyses. Our results show that although Diaptomid species differ in their reproductive traits, they also differ in other morphological traits that might indicate ecological differences among species and populations.     

Genetic, geographic, and environmental correlates of human temporal bone variation

Temporal bone shape has been shown to reflect molecular phylogenetic relationships among hominoids and offers significant morphological detail for distinguishing taxa. Although it is generally accepted that temporal bone shape, like other aspects of morphology, has an underlying genetic component, the relative influence of genetic and environmental factors is unclear. To determine the impact of genetic differentiation and environmental variation on temporal bone morphology, we used three-dimensional geometric morphometric techniques to evaluate temporal bone variation in 11 modern human populations. Population differences were investigated by discriminant function analysis, and the strength of the relationships between morphology, neutral molecular distance, geographic distribution, and environmental variables were assessed by matrix correlation comparisons. Significant differences were found in temporal bone shape among all populations, and classification rates using cross-validation were relatively high. Comparisons of morphological distances to molecular distances based on short tandem repeats (STRs) revealed a significant correlation between temporal bone shape and neutral molecular distance among Old World populations, but not when Native Americans were included. Further analyses suggested a similar pattern for morphological variation and geographic distribution. No significant correlations were found between temporal bone shape and environmental variables: temperature, annual rainfall, latitude, or altitude. Significant correlations were found between temporal bone size and both temperature and latitude, presumably reflecting Bergmann's rule. Thus, temporal bone morphology appears to partially follow an isolation by distance model of evolution among human populations, although levels of correlation show that a substantial component of variation is unexplained by factors considered here.     

GROUP SIZE FACTORS AND GEOGRAPHIC VARIATION OF MORPHOMETRIC CORRELATION

Within-locality correlations among eight morphological traits of the fundatrix and among 15 morphological traits of the alate fundatrigeniae of the aphid Pemphigus populicaulis Fitch were examined for among-locality variation. A jackknife procedure revealed highly significant differences among correlation matrices representing 34 local samples from eastern North America. Most bivariate correlations also differed significantly among samples. Although very low correlations cannot differ, for moderate or strong correlations the average magnitude of correlation is not a good predictor of the degree of interlocality difference. Nearly half of the variation among localities is in the level of “overall correlation,” which is positively correlated with intralocality size variation. Despite significant differences among localities, spatial autocorrelation tests failed to reveal any significant geographic pattern in correlations. Monte Carlo experiments suggest that if geographic patterns in the correlations were of the same magnitude as those for the means of these traits, some of these patterns would have been detected. Factor analyses of the pooled within-locality correlation matrices, after oblique rotation to simple structure, reveal appendage and body-size factors for both alates and stem mothers. In general, correlations between traits with high loadings on the same factor differ among localities, whereas substantial correlations that do not vary geographically are between traits that are not well resolved by the factor analyses. It is hypothesized that the apparently random geographic differences in correlation are caused by chance differences in the mode of response to short-term selection. Geographic patterns in trait means are established by selection, but, because local population sizes are finite, similar response to selection occurs by diverse physiological or developmental mechanisms in different populations, just as replicate lines in artificial selection experiments may achieve the same response by diverse mechanisms. These diverse mechanisms of response will have diverse effects on genetic variance and covariance, causing correlation patterns to vary geographically. Several forces will oppose continued divergence of these patterns.     

Levels of variation in stress resistance in drosophila among strains, local populations, and geographic regions: patterns for desiccation, starvation, cold resistance, and associated traits

Stress resistance traits in Drosophila often show clinal variation. Although these patterns suggest selection, there is generally no attempt to test how large differences at the geographical level are relative to levels of variation within and between local populations. Here we compare these levels in D. melanogaster from temperate Tasmania versus tropical northern Queensland by focusing on adult resistance to desiccation, cold and starvation stress, as well as associated traits (size, lipid content). For starvation and desiccation resistance, levels of variation were highest among strains from the same population. whereas there was little differentiation among local populations and a low level of differentiation at the geographic level. For adult cold resistance, there was local differentiation and strain variation but no geographic variation. For size (thorax length), geographic differentiation was higher despite some overlap among strains from the tropical and temperate locations. Finally, for lipid levels there was only evidence for variation among strains. The low level of differentiation among geographic locations for stress resistance was further verified with the characterization of isofemale strains from 18 locations along a coastal transect extending from Tasmania to northern Queensland. Crosses among some of the isofemale strains showed that results were not confounded by inbreeding effects. Strains derived from a cross between a tropical and temperate strain differed for all traits, and variation among strains for body size was higher than strain variation within the geographic regions. Unlike in previous studies, lipid content and starvation resistance were not correlated in any set of strains, but there was a correlation between cold resistance and lipid content. There was also a correlation between desiccation resistance and size but only in the geographic cross strains. These findings suggest a large amount of variation in stress resistance at the population level and inconsistent correlation patterns across experimental approaches.     

茶条槭不同海拔种群的表型多样性

为了揭示茶条槭（Acerginnala）不同海拔种群表型变异程度和变异规律,以山西七里峪天然分布的茶条槭为研究对象,调查不同海拔种群的种实和叶表型性状,采用方差分析、相关分析、聚类分析等方法,分析种群的表型多样性。结果表明：17个表型性状中16个存在显著差异,占总表型性状的94.12%。在物种水平上各个性状表现出较丰富的变异,变异系数（CV）在7.05%～38.12%之间。茶条槭种群具有高的表型多样性（1.9253）,5个不同海拔种群的平均表型多样性指数为1.9022～1.9837。种群间的表型分化系数均值（13.79%）小于种群内变异（82.71%）,种群内的变异是表型变异的主要来源。各表型性状及表型多样性指数与土壤中的N、K、AN、AK、AP、OR、MC表现出显著或极显著的相关关系（P〈0.05）,但与海拔高度呈现出不显著的相关性。UPGMA聚类分析显示5个种群形成明显的两组,与其地理分布相一致。不同海拔种群所处微生境的异质性是引起种群间差异的主要原因。茶条槭种群内、种群间变异的利用对其遗传改良具有重要的意义。     

Genetic and morphological differentiation in Populus nigra L.: isolation by colonization or isolation by adaptation?

Identifying processes underlying the genetic and morphological differences among populations is a central question of evolutionary biology. Forest trees typically contain high levels of neutral genetic variation, and genetic differences are often correlated with geographic distance between populations [isolation by distance (IBD)] or are due to historic vicariance events [isolation by colonization (IBC)]. In contrast, morphological differences are largely due to local adaptation. Here, we examined genetic (microsatellite) and morphological (from a common garden experiment) variation in Populus nigra L., European black poplar, collected from 13 sites across western Europe and grown in a common garden in Belgium. Significant genetic differentiation was observed, with populations from France displaying greater admixture than the distinct Spanish and central European gene pools, consistent with previously described glacial refugia (IBC). Many quantitative traits displayed a bimodal distribution, approximately corresponding to small‐leaf and large‐leaf ecotypes. Examination of nine climatic variables revealed the sampling locations to have diverse climates, and although the correlation between morphological and climatic differences was significant, the pattern was not consistent with strict local adaptation. Partial Mantel tests based on multivariate summary statistics identified significant residual correlation in comparisons of small‐leaf to large‐leaf ecotypes, and within the small‐leaf samples, but not within large‐leaf ecotypes, indicating that variation within the small‐leaf morphotype in particular may be adaptive. Some small‐leaf populations experience climates very similar to those in large‐leaf sites. We conclude that adaptive differentiation and persistent IBC acted in combination to produce the genetic and morphological patterns observed in P. nigra.     

我国格木的地理分布与种实表型变异

在调查格木(Erythrophleum fordii)主要天然分布区及资源现状的基础上, 研究了荚果和种子的11个表型性状在8个格木天然群体内和群体间的变异规律, 探讨了种实表型变异与地理、环境因子的相关性。结果显示: 格木天然林主要分布在广西、广东和福建3省区北回归线附近低海拔地区, 大部分呈散生状态或小群体; 格木荚果和种子的长度、宽度、形态指数以及每个荚果内种子数、种子厚度和千粒重在群体间和群体内单株间均存在显著差异; 荚果性状在群体间和群体内的变异均大于种子性状; 每个荚果内种子数与荚果的长度、形态指数以及种子的长度、大小呈显著正相关, 种子长度和宽度与荚果大小、种子千粒重与荚果宽度均呈显著正相关; 荚果形态指数与经度呈显著负相关, 种子千粒重与纬度、种子宽度与海拔和年降雨量、种子形态指数与年均气温、种子大小与年降雨量均呈显著正相关。通过聚类分析可将8个格木群体分为3类: GX03单独为1类, GX01与GX02聚为1类, 其余5个群体聚为1类。研究结果为进一步开展格木保护生物学和遗传育种研究奠定了基础。     

不同居群塔里木沙拐枣(Calligonum roborowskii A. Los.)果实形态变异研究

应用方差分析、聚类分析、主成分分析、相关性分析等方法,对塔里木盆地分布的塔里木沙拐枣(Calligonum roborowskii A.Los.)5个居群的果实形态进行了形态差异分析。单因素方差分析显示果实长度、果实宽度、果实长宽/果实宽度比、刺毛长度、两肋间距、两刺间距、取刺毛后的瘦果长度、瘦果宽度、瘦果长度/瘦果宽度比与每果肋数等10个果实性状在不同居群间具有极显著差异;主成分分析显示两刺间距,两肋间距,刺毛长度等3个性状是造成各居群果实表型差异的主要指标;根据果实形态地理距离比较近的居群聚为一大支;相关性分析显示果实长度与果实宽度,海拔与刺毛长度极显著正相关。     

Geographic variation in body size, sexual size dimorphism and fitness components of a seed beetle: local adaptation versus phenotypic plasticity

Variation in body size, growth and life history traits of ectotherms along latitudinal and altitudinal clines is generally assumed to represent adaptation to local environmental conditions, especially adaptation to temperature. However, the degree to which variation along these clines is due to adaptation vs plasticity remains poorly understood. In addition, geographic patterns often differ between females and males – e.g. sexual dimorphism varies along latitudinal clines, but the extent to which these sex differences are due to genetic differences between sexes vs sex differences in plasticity is poorly understood. We use common garden experiments (beetles reared at 24, 30 and 36°C) to quantify the relative contribution of genetically‐based differentiation among populations vs phenotypic plasticity to variation in body size and other traits among six populations of the seed‐feeding beetle Stator limbatus collected from various altitudes in Arizona, USA. We found that temperature induces substantial plasticity in survivorship, body size and female lifetime fecundity, indicating that developmental temperature significantly affects growth and life history traits of S. limbatus. We also detected genetic differences among populations for body size and fecundity, and genetic differences among populations in thermal reaction norms, but the altitude of origin (and hence mean temperature) does not appear to explain these genetic differences. This and other recent studies suggest that temperature is not the major environmental factor that generates geographic variation in traits of this species. In addition, though there was no overall difference in plasticity of body size between males and females (when averaged across populations), we did find that the degree to which dimorphism changed with temperature varied among populations. Consequently, future studies should be extremely cautious when using only a few study populations to examine environmental effects on sexual dimorphism.     

高原鼢鼠(Eospalax baileyi)头骨形态的地理分化

运用单因素方差分析、主成分分析、判别分析和聚类分析,对高原鼢鼠(Eospalax baileyi)4个地区(临潭、天祝、玛曲和碌曲)8个地理群体的头骨形态特征进行综合分析,比较13个特征变量的地理分异,挖掘形态特征的主要变量,并探讨其形态变异与环境的关系。结果发现,群体间13个特征变量均存在显著差异,主成分分析表明13个头骨特征变量可用3个主成分来表述,其累计贡献率达96.981%。颅全长、上齿列长及齿隙长是高原鼢鼠头骨发生分化的主要变量。天祝种群与碌曲种群,及玛曲种群与临潭种群都有重叠,其中碌曲的两个种群相似性最高,玛曲种群和临潭种群与其他种群几乎无重叠,显示完全分化,聚类分析结果与判别分析结果一致。头骨形态与地理因子的相关性分析发现头骨形态大小与海拔成显著的正相关关系。综合分析认为地理隔离、栖息地海拔因子影响下的生态条件等是高原鼢鼠头骨分化的主要因素。     

Altitudinal genetic and morphometric variation among populations of Culex theileri Theobald (Diptera: Culicidae) from northeastern Turkey

Enviromental conditions, including such important climatic variables as temperature and precipitation, change with altitude; thus, elevation plays a significant role in determining population and community structure in a variety of organisms. Using single nucleotide polymorphisms (SNPs) and geometric morphometrics, nine populations of Culex theileri Theobald occurring in different ecological subregions at altitudes between 808-2,130 m in northeastern Turkey were compared. The wing size and shape data indicate that there are significant phenotypic differences among them, while Cx theileri populations are not genetically differentiated in the northeast part of Turkey. The size and shape variation analysis of wings showed that there is a positive correlation between wing (body) size/shape and altitude.     

光肩星天牛两型种群表型多样性分析

【目的】光肩星天牛Anoplophora glabripennis(Motschulsky)是国内最重要的林木蛀干害虫之一,在中国分布范围较广。近年来,形态学以及分子生物学的研究表明,光肩星天牛与黄斑星天牛A.nobilis(Ganglbauer)很可能是同一种的不同型。定量研究光肩星天牛两型的差异与表型多样性。【方法】作者以光肩星天牛的20个地理种群的光肩星天牛分布区为研究对象,采用巢式方差分析和聚类分析对其头长、头后缘宽、前胸后缘宽等13个表型性状进行多样性分析。【结果】表型特征在群体间与群体内均存在着广泛的变异,13个性状的平均表型分化系数为11.78%,群体内变异是其表型性状变异的主要来源;后翅长度与经度呈极显著负相关,与海拔极显著正相关以及与年降水量呈显著负相关。体长与鞘翅斑纹颜色与海拔高度分别呈显著正相关和负相关关系;在不同地理种群中,鞘翅斑纹颜色的分化系数达到最大,为50.53%;而以鞘翅斑纹颜色分类的两型差异显示各性状的表型分化系数均大幅度降低。【结论】本研究首次将鞘翅斑纹的颜色进行数字化处理,并进行分类,结果显示各个颜色类群的分化系数均大幅度减小,说明颜色类群之间的分化要小于地理隔离所造成的差异,进一步验证了光肩星天牛与黄斑星天牛为同一种的不同型。     

Intraspecific variation in laryngeal and ear morphology in male cricket frogs (Acris crepitans)

In a previous report, the authors found significant population variation in the calls of cricket frogs ( Acris crepitans ) that could not be explained by geographic variation in body size alone. Here we extend that work by investigating intraspecific population variation in the morphological characteristics underlying acoustic communication in male cricket frogs from several sites in Texas. We measured the volumes of laryngeal and auditory components responsible for the generation or reception of species-specific vocalizations in male frogs from eight populations. We found significant differences among populations in body size, as well as all the laryngeal and ear components we measured. With the exception of vocal cord and extracolumella volumes, the volumes of these anatomical structures differ among populations independently of body size as determined by a covariate analysis with snout-vent length as the covariate. Call dominant frequency differs among populations in a clinal pattern and head width, arytenoid cartilage, vocal cord and dilator muscle volume show a similar pattern when the residuals of the regression of morphological component on SVL are assessed for this trend. The results show that both larynx and ear structures can change in size independently of body size, yielding significant geographic variation in the behavioral and physiological expressions of the acoustic communication system underlying mate choice.     

我国格木的地理分布与种实表型变异

在调查格木（Erythrophleum fordii）主要天然分布区及资源现状的基础上,研究了荚果和种子的11个表型性状在8个格木天然群体内和群体间的变异规律,探讨了种实表型变异与地理、环境因子的相关性。结果显示：格木天然林主要分布在广西、广东和福建3省区北回归线附近低海拔地区,大部分呈散生状态或小群体：格木荚果和种子的长度、宽度、形态指数以及每个荚果内种子数、种子厚度和千粒重在群体间和群体内单株间均存在显著差异：荚果性状在群体间和群体内的变异均大于种子性状：每个荚果内种子数与荚果的长度、形态指数以及种子的长度、大小呈显著正相关,种子长度和宽度与荚果大小、种子千粒重与荚果宽度均呈显著正相关：荚果形态指数与经度呈显著负相关,种子千粒重与纬度、种子宽度与海拔和年降雨量、种子形态指数与年均气温、种子大小与年降雨量均呈显著正相关。通过聚类分析可将8个格木群体分为3类：GX03单独为1类,GX01与GX02聚为1类,其余5个群体聚为1类。研究结果为进一步开展格木保护生物学和遗传育种研究奠定了基础。     

Allometric influence on phenotypic variation in the Song Sparrow (Melospiza melodia)

Song Sparrow ( Melospiza melodia ) populations found along the Pacific Coast of North America, from Baja California to the islands off the coast of Alaska, exhibit extensive morphological variation. With a multivariate analysis of size and shape, I describe a portion of this pattern and examine how it could be maintained despite gene flow among the populations. Because shape differences fall along geographic barriers, I suggest that similarities among Song Sparrow populations in multivariate shape reflect their pattern of genetic relatedness. A general pattern of Song Sparrow post-nestling growth allometry has been discovered: bill characteristics are positively allometric and all other characteristics are negatively allometric. In contrast to shape, multivariate patterns of body size variation do not correspond to geographic relationships. In combination with evidence of Song Sparrow phenotypic plasticity, it is proposed that multivariate body size is an environmentally plastic trait and that specific traits exhibit levels of phenotypic plasticity in proportion to their rate of growth with respect to body size. In this way local environmental factors which alter body size may change an entire suite of allometrically related traits and thus create striking patterns of morphological variation.     

Flower morphometry of Rhizophora mangle (Rhizophoraceae): geographical variation in Mexican populations

We explored the patterns of intra- and interpopulation variation in flower morphology of the red mangrove, Rhizophora mangle. Twelve populations in Mexico were studied: five from the Gulf of Mexico and the Caribbean Sea, and seven from the Pacific Coast. Six metric floral attributes were measured from a sample of 1370 flowers. Significant differences among populations were found for all six attributes. Because floral attributes were all correlated, scores derived from principal factor analysis were used to describe the variation in flower morphology. Two factors explained essentially all of the variance in flower morphology. Corolla and calyx size had a strong effect on factor 1, while gynoecium size had the higher effect on factor 2. Nested analyses of variance on the scores from both factors revealed significant differences among coasts, among populations within coasts, and among plants within populations. Nonetheless, this variation cannot be explained as a result of clinal variation, as indicated by a series of regression analyses. Cluster analysis (UPGMA) showed that a population from the Pacific coast was clustered together with those of the Atlantic, and the arrangement of populations within each coast showed no evident geographical pattern. We propose that frequent events of extinction and recolonization by a few individuals, followed by selfing, may produce differentiation among populations of red mangrove.     

Altitudinal distribution and body resource allocation in a high mountain social wasp (Hymenoptera: Vespidae)

Jame's rule proposes a direct relationship between body size and altitude. There are several studies about this rule; however, few studies analyze proportional changes in body parts along gradients. The morphological variation of Agelaia pallipes (Olivier) in five sites along an altitudinal gradient (2600-3380 m) in the Santuario de Iguaque, Colombia, were studied in order to test whether or not the species follows Jame's rule, and whether body parts follow a homogeneous variation. Body variation analysis was conducted through multivariate analysis of variance (MANOVA) and the relationship between altitude and each morphometric measurement was studied through regression analyses. The MANOVA indicated significant differences among sites. An increase in altitude leads to a reduction in body size, especially in hind femur length and head width. However, measurements linked to flight such as mesosoma height, mesoscutum width, and fore wing size showed a reverse tendency. Possibly all described changes are consequence of both reduction on food availability and lower atmospheric pressure. The low temperature of high areas may strongly limit foraging and thus food availability. Lower atmospheric pressure reduces flight potential and may result in an increase in size of both wings and flight muscles. This paper underscores the need to study in detail the changes in body proportions in species with wide distribution ranges in latitude and altitude.     

The evolution of the phenotypic covariance matrix: evidence for selection and drift in Melanoplus

Phenotypic variation in trait means is a common observation for geographically separated populations. Such variation is typically retained under common garden conditions, indicating that there has been evolutionary change in the populations, as a result of selection and/or drift. Much less frequently studied is variation in the phenotypic covariance matrix (hereafter, P matrix), although this is an important component of evolutionary change. In this paper, we examine variation in the phenotypic means and P matrices in two species of grasshopper, Melanoplus sanguinipes and M. devastator. Using the P matrices estimated for 14 populations of M. sanguinipes and three populations of M. devastator we find that (1) significant differences between the sexes can be attributed to scaling effects; (2) there is no significant difference between the two species; (3) there are highly significant differences among populations that cannot be accounted for by scaling effects; (4) these differences are a consequence of statistically significant patterns of covariation with geographic and environmental factors, phenotypic variances and covariances increasing with increased temperature but decreasing with increased latitude and altitude. This covariation suggests that selection has been important in the evolution of the P matrix in these populations Finally, we find a significant positive correlation between the average difference between matrices and the genetic distance between the populations, indicating that drift has caused some of the variation in the P matrices.