雄性黄山短尾猴颅骨变量的异速生长研究

对雄性黄山短尾猴颅骨标本的36项主要形态变量指标进行定点测量,并进行了初步的统计分析和异速生长分析。结果表明,大多数变量的统计值在雄性个体间的变化范围都比较大,2/3的变量表现为正的异速生长,1/3的变量表现为负异速生长。颅骨变量的生长存在年龄及部位间的差异,这些差异与雄性的不同生长发育时期、在社群中的不同地位和竞争压力以及取食习性有关。     

武功山亚高山草甸群落优势植物野古草和芒异速生长对气候变暖的响应

气候变暖正持续影响着陆地生态系统的结构和功能, 一直是备受关注的热点问题。异速生长关系被认为是生物界中的一种普遍规律, 但我们对于气候变暖如何影响植物异速生长特征所知甚少。该文采用开顶式增温小室对野外自然生境进行模拟增温的方法, 研究了气候变暖对江西武功山亚高山草甸植物群落优势种野古草(Arundinella anomala)和芒(Miscanthus sinensis)异速生长特征的影响。结果表明: 野古草和芒的大多数形态指标之间均具有显著或极显著相关生长关系和异速生长关系, 气候变暖强化了两种禾本科植物大多数形态特征之间的异速生长, 或改变了其原有的生长关系。气候变暖还导致野古草和芒的基部茎粗与其高度、穗长间由原有的等速生长关系转变为异速生长关系; 野古草基部茎粗与小穗数间的异速生长随着温度升高而趋于增强。气候变暖导致野古草个体高度与其叶片长度的异速生长关系转变为等速生长关系, 而芒有相反表现。同时, 增温促进了野古草株高及叶鞘长的生长, 较强增温则改变了芒株高和叶鞘长之间的生长关系; 野古草和芒的叶片形态特征之间几乎都表现为类似的异速生长关系, 增温对其异速生长指数无显著影响。研究表明气候变暖对不同植物和植物构件具有差异性影响, 这种差异性往往与植物的适应性有关。     

四种一年生荒漠植物构件形态与生物量间的异速生长关系

1年生草本植物是古尔班通古特沙漠夏秋季节草本层片的主要组成部分。选择4种藜科1年生草本植物(刺沙蓬、沙蓬、角果藜和对节刺)作为研究对象,对比分析了各物种构件形态特征、生物量分配以及它们之间的异速生长关系。结果表明:沙蓬个体最大,其次为刺沙蓬,角果藜和对节刺个体最小;对节刺具有最大的根冠比(R/S),其次是刺沙蓬,沙蓬和角果藜R/S最小。4种植物构件形态与生物量间均呈显著正相关,表现出强烈的协同变化趋势。R/S与绝大部分指标间呈显著负相关,表明随个体增大地下生物量分配比例逐渐减小。4种植物各构件形态、地上及地下生物量间大部分呈指数1.0的异速生长关系,但各物种间的异速生长指数绝大部分无显著差异且具有共同的异速生长指数。研究表明:尽管物种不同、个体大小迥异,但4种1年生植物构件特征间多具有相同的生长速率和协同变化特征,体现了1年生植物这一生活型内的不同物种对干旱荒漠环境的趋同适应。     

着生位置对水曲柳小叶性状变异及性状间相关性的影响

复叶植物相比单叶植物更具生长优势, 但复叶内部小叶性状及其相关关系是否受到着生位置影响尚未可知。该研究以东北典型复叶植物水曲柳(Fraxinus mandshurica)为研究对象, 测定复叶内部不同着生位置小叶的叶厚(LT)、叶面积(LA)、叶干物质含量(LDMC)、比叶面积(SLA)、叶氮含量(LNC)和叶磷含量(LPC), 分析上述6种小叶性状及其生长关系在复叶内部的变异, 并分别通过最小显著性差异(LSD)法以及标准化主轴(SMA)法检验着生位置对小叶性状及性状间生长关系是否存在显著影响。结果表明: (1) LT、LA、LDMC和LNC随小叶着生位置级别增加(从复叶顶端至复叶基部)呈减小趋势, 但SLA和LPC呈增大趋势。(2)复叶内部, LNC与SLA间以及LT与LDMC间表现为同速生长关系, LT、SLA、LPC 3个性状与LA间, SLA、LNC、LPC 3个性状与LDMC间以及LPC与LT间均表现为异速生长关系。(3)小叶着生位置对LA与LT、SLA、LPC之间的相关关系存在显著影响, LT、SLA与LA的斜率在三级小叶(复叶中部)附近达到最大值, LT、LPC与LA的斜率绝对值在六级小叶(复叶基部)处达到最小值。整体而言, 复叶内部小叶性状随着生位置存在一定变异规律, 小叶性状间多表现为异速生长关系, 且小叶性状间的生长关系一定程度上受着生位置的调控。     

兰州北山侧柏株高与冠幅、胸径异速生长关系的坡向差异性

植物功能性状之间的关系是其提高自身空间资源利用能力的一种生态策略,反映了植物与环境协同适应的表型可塑性机制。本文利用Arc GIS建立研究区域的数字高程模型(DEM),并提取样地坡向数据,采用标准化主轴估计(standardized major axis estimation,SMA)方法,研究了兰州市北山不同坡向人工林侧柏株高-冠幅和株高-胸径的异速生长关系。结果表明,侧柏胸径在各坡向上存在显著性差异(P0.05),株高和冠幅在东坡和西坡之间无显著性差异(P0.05);侧柏株高与冠幅的异速生长关系存在坡向差异,南坡冠幅的生长速率大于株高的生长速率,北坡冠幅的生长速率小于株高的生长速率,东坡和西坡株高、冠幅的生长速率相近;各坡向上侧柏胸径的生长速率均大于株高的生长速率,二者异速生长关系的坡向差异不明显(P0.05)。侧柏冠幅、胸径与株高异速关系在各坡向上的不同表现,反映了异质性生境中植物主要构件的投资权衡机制。     

现代各主要人群额骨3D几何形态的对比

额骨是连接面颅和脑颅的重要头骨组成部分,关于现代各个人种的额骨形态是否存在明显的差别,这些人种额骨的基本形态如何,变异范围以及与其他人群的相似与差异等问题都尚未完全厘清。而额骨的很多特征由于技术手段的限制很难进行测量和准确的描述比较。鉴于这些问题,本文将采用基于三维表面半标志点的几何形态测量方法,研究东亚现代人额骨的表面形态及其变异范围,并与欧洲,东南亚,美洲,非洲以及澳洲的现代人群的额骨形态进行对比,为对比不同人群的形态研究建立基础数据。结果显示,额骨形态的变异主要表现在:1)额骨鳞部的额结节和正中矢状脊共同向前隆起或回缩以及相对额骨宽度;2)眉弓的粗壮程度,额结节的侧向发育程度和正中矢状脊的发育情况。为了进一步揭示中国现代人与其他人群在额骨形态上的关系,本文还探讨了额骨大小在不同人群中的差异。结果显示,东亚现代人和欧洲现代人额骨中心大小值的中位数最大,澳洲现代人的最小。东亚现代人的额骨形态与澳洲,欧洲和非洲均有非常显著的差异。为了检验额骨的形态是否与遗传距离一致,作者还对额骨形态距离和遗传距离做了相关性分析。结果显示,不同人群的额骨形态与其遗传距离呈显著的相关性,说明本研究结果中不同人群额骨形态上的差异大小可以在一定程度上反映其遗传距离,并可能进一步反映人群历史。东亚现代人的额骨平均形态在与各个人群比较过程中表现出一致性特征,可能在一定程度上反映了东亚现代人群的进化过程是相对独立的。未来额骨的三维几何形态测量可通过扩大标本数量进一步探讨不同性别和不同演化阶段之间的差异。     

不同生境入侵植物北美车前繁殖器官性状变异与权衡特征

提高繁殖输出是入侵植物成功入侵的重要机制,但不同生境间繁殖器官性状变异特征尤其是性状权衡关系可能会存在差异。以入侵植物北美车前（Plantago virginica）为研究对象,采集草坪、荒地和林下3个生境的植物花序,探究花穗及花序柄的形态、生物量及其异速生长关系在不同生境间的差异性。结果表明：不同生境北美车前大部分花序形态与生物量指标存在显著差异,草坪和荒地生境花序属细长型,而林下生境则为矮壮型。北美车前繁殖器官不同性状间的异速生长关系既有保守型也有易变型,体现出不同的环境敏感性。不同生境间北美车前繁殖器官资源分配的个体大小依赖关系也存在不一致性。可见,北美车前花序性状及资源分配在不同生境间既存在一定的可塑性也具有相对保守性,这可能是其高入侵能力的重要原因。     

亚热带常绿林不同冠层小枝叶面积-叶生物量关系研究

叶面积与叶生物量的关系对于理解植物叶片的碳收益和投资权衡策略具有重要意义。收益递减假说认为植物的叶面积与叶生物量成显著异速生长关系，其异速生长指数<1.0，但该假说是否适用于不同生活型（常绿与落叶）亚热带木本植物不同冠层高度（上下冠层）当年生小枝的叶片仍不清楚。以江西亚热带常绿阔叶林的69种常绿与落叶木本植物当年生小枝上的叶为研究对象，采用标准化主轴回归估计（standardized major axis estimation，SMA）方法检验不同冠层高度和生活型叶面积与叶生物量的异速生长关系。结果显示：（1）当年生小枝叶生物量在不同冠层高度和生活型的植物中无显著差异（P>0.05），叶面积在常绿和落叶植物中有显著差异（P<0.05），常绿和落叶植物的比叶重存在显著差异（P<0.05），而落叶植物的比叶重在不同冠层高度存在显著差异（P<0.05），同一冠层，常绿植物比叶重显著高于落叶植物（P<0.05）；（2）69种植物的叶面积与叶生物量异速生长指数具有物种特异性，60.9%的物种叶面积与叶生物量呈等速生长关系；（3）不同冠层和生活型植物的叶面积与叶生物量呈等速生长关系，但其异速生长常数在不同冠层高度与生活型间存在差异。这些结果表明冠层高度和生活型未改变叶面积-生物量之间的等速生长关系，不支持"收益递减"假说。     

兰州市典型绿化树种叶性状间的权衡关系

植物叶性状的权衡关系反映了植物对环境的高度适应性及其在复杂生境下的自我调控能力,了解半干旱区城市绿化树种叶性状间的权衡关系,比较不同生长型(针叶和阔叶)树种异速生长的差异有助于进一步认识植物的进化机制。以兰州市典型绿化树种(13种针叶树和47种阔叶树)为对象,测量部分叶性状,采用标准化主轴估计和系统独立比较分析的方法比较不同性状间的权衡关系。结果表明:不同生长型树种叶面积、叶体积与叶片干重之间均为等速生长关系,针叶和阔叶树种间并无显著差异;叶厚与叶面积间为"此消彼长"的权衡关系,但并不显著;阔叶叶长与叶宽间异速生长斜率为0.764。兰州市典型绿化树种叶性状间的权衡可能是长期适应黄土高原特殊生境的自适应过程,也说明部分性状间存在协变关系,阔叶绿化树种的权衡表明其符合"快速投资-收益"特征。     

祁连山高寒草地甘肃臭草叶性状与坡向间的关系

植物功能性状可反映植物对环境的适应。在祁连山高寒退化草地, 利用ArcGIS建立研究区域的数字高程模型, 提取坡向数据, 采用标准化主轴估计方法(standardized major axis estimation, SMA), 研究了不同坡向甘肃臭草(Melica przewalskyi)叶性状间的关系。结果表明: 1)甘肃臭草叶面积和叶体积在北坡最大, 东坡、西坡、南坡逐渐减小, 叶干质量无显著变化; 2)叶面积与叶干质量在北坡、东坡和西坡呈等速生长关系, 在南坡呈异速生长关系, 且叶干质量的增长速度大于叶面积的增长速度; 3)叶体积与叶干质量在4个坡向上呈异速生长关系, 且叶干质量的增长速度均小于叶体积的增长速度。甘肃臭草叶性状关系随坡向的变化反映了该物种在异质生境中具有较强的叶片形态可塑性, 从而有利于其适应和占据高寒退化生境。     

An ontogenetic perspective on the study of sexual dimorphism, phylogenetic variability, and allometry of the skull of European ground squirrel, Spermophilus citellus (Linnaeus, 1766)

Most studies of morphological variability in or among species are performed on adult specimens. However, it has been proven that knowledge of the patterns of size and shape changes and their covariation during ontogeny is of great value for the understanding of the processes that produce morphological variation. In this study, we investigated the patterns of sexual dimorphism, phylogenetic variability, and ontogenetic allometry in the Spermophilus citellus with geometric morphometrics applied to cross-sectional ontogenetic data of 189 skulls from three populations (originating from Burgenland, Banat, and Dojran) belonging to two phylogenetic lineages (the Northern and Southern). Our results indicate that sexual dimorphism in the ventral cranium of S. citellus is expressed only in skull size and becomes apparent just before or after the first hibernation because of accelerated growth in juvenile males. Sexes had the same pattern of ontogenetic allometry. Populations from Banat and Dojran, belonging to different phylogroups, were the most different in size but had the most similar adult skull shape. Phylogenetic relations among populations, therefore, did not reflect skull morphology, which is probably under a significant influence of ecological factors. Populations had parallel allometric trajectories, indicating that alterations in development probably occur prenatally. The species’ allometric relations during cranial growth showed characteristic nonlinear trajectories in the two northern populations, with accelerated shape changes in juveniles and continued but almost isometric growth in adults. The adult cranial shape was reached before sexual maturity of both sexes and adult size after sexual maturity. The majority of shape changes during growth are probably correlated with the shift from a liquid to a solid diet and to a lesser degree due to allometric scaling, which explained only 20 % of total shape variation. As expected, viscerocranial components grew with positive and neurocranial with negative allometry.     

Static allometry of unicellular green algae: scaling of cellular surface area and volume in the genus Micrasterias (Desmidiales)

The surface area‐to‐volume ratio of cells is one of the key factors affecting fundamental biological processes and, thus, fitness of unicellular organisms. One of the general models for allometric increase in surface‐to‐volume scaling involves fractal‐like elaboration of cellular surfaces. However, specific data illustrating this pattern in natural populations of the unicellular organisms have not previously been available. This study shows that unicellular green algae of the genus Micrasterias (Desmidiales) have positive allometric surface‐to‐volume scaling caused by changes in morphology of individual species, especially in the degree of cell lobulation. This allometric pattern was also detected within most of the cultured and natural populations analysed. Values of the allometric S:V scaling within individual populations were closely correlated to the phylogenetic structure of the clade. In addition, they were related to species‐specific cellular morphology. Individual populations differed in their allometric patterns, and their position in the allometric space was strongly correlated with the degree of allometric S:V scaling. This result illustrates that allometric shape patterns are an important correlate of the capacity of individual populations to compensate for increases in their cell volumes by increasing the surface area. However, variation in allometric patterns was not associated with phylogenetic structure. This indicates that the position of the populations in the allometric space was not evolutionarily conserved and might be influenced by environmental factors.     

A non‐invasive geometric morphometrics method for exploring variation in dorsal head shape in urodeles: sexual dimorphism and geographic variation in Salamandra salamandra

The study of morphological variation among and within taxa can shed light on the evolution of phenotypic diversification. In the case of urodeles, the dorso‐ventral view of the head captures most of the ontogenetic and evolutionary variation of the entire head, which is a structure with a high potential for being a target of selection due to its relevance in ecological and social functions. Here, we describe a non‐invasive procedure of geometric morphometrics for exploring morphological variation in the external dorso‐ventral view of urodeles' head. To explore the accuracy of the method and its potential for describing morphological patterns we applied it to two populations of Salamandra salamandra gallaica from NW Iberia. Using landmark‐based geometric morphometrics, we detected differences in head shape between populations and sexes, and an allometric relationship between shape and size. We also determined that not all differences in head shape are due to size variation, suggesting intrinsic shape differences across sexes and populations. These morphological patterns had not been previously explored in S. salamandra , despite the high levels of intraspecific diversity within this species. The methodological procedure presented here allows to detect shape variation at a very fine scale, and solves the drawbacks of using cranial samples, thus increasing the possibilities of using collection specimens and alive animals for exploring dorsal head shape variation and its evolutionary and ecological implications in urodeles. J. Morphol. 278:475–485, 2017. © 2017 Wiley Periodicals, Inc.     

Spatial variation of shell morphometrics in the subantarctic land snail <Emphasis Type="Italic">Notodiscus hookeri</Emphasis> from Crozet and Kerguelen Islands

The land snail Notodiscus hookeri, widely distributed in subantarctic islands, shows a large intraspecific variation in shell morphology. In the present work, shell size and form of individuals from populations located in Crozet and Kerguelen archipelagos were investigated by means of multivariate statistics. Variation in shell morphometrics was analysed after the partitioning of the overall variation into size and shape components by means of a principal component-based approach. Shell size shows a significant spatial heterogeneity, which seems essentially related to environmental pressures. Previous works pointed to a greater conchological variation between populations from Kerguelen but present observations show that intra-island variances are not significantly different in the two islands studied. Variation in shell shape splits the populations into two main entities because of different allometric relationships between two shell height components and all other measurements. However, using geographical affinities of populations as instrumental variables shows that more complex environmental features interfered in population clustering.     

Intraspecific evidence from guppies for correlated patterns of male and female genital trait diversification

The role of sexual selection in fuelling genital evolution is becoming increasingly apparent from comparative studies revealing interspecific divergence in male genitalia and evolutionary associations between male and female genital traits. Despite this, we know little about intraspecific variance in male genital morphology, or how male and female reproductive traits covary among divergent populations. Here we address both topics using natural populations of the guppy, Poecilia reticulata, a livebearing fish that exhibits divergent patterns of male sexual behaviour among populations. Initially, we performed a series of mating trials on a single population to examine the relationship between the morphology of the male's copulatory organ (the gonopodium) and the success of forced matings. Using a combination of linear measurements and geometric morphometrics, we found that variation in the length and shape of the gonopodium predicted the success of forced matings in terms of the rate of genital contacts and insemination success, respectively. We then looked for geographical divergence in these traits, since the relative frequency of forced matings tends to be greater in high-predation populations. We found consistent patterns of variation in male genital size and shape in relation to the level of predation, and corresponding patterns of (co)variation in female genital morphology. Together, these data enable us to draw tentative conclusions about the underlying selective pressures causing correlated patterns of divergence in male and female genital traits, which point to a role for sexually antagonistic selection.     

Wing size and shape variation of Phlebotomus papatasi (Diptera: Psychodidae) populations from the south and north slopes of the Atlas Mountains in Morocco

The wing shape and size morphology of populations of the medically important phlebotomine sand fly, Phlebotomus papatasi, were examined in two endemic (south of the Atlas Mountains) and nonendemic (north of the Atlas Mountains) foci of cutaneous leishmaniasis by using geometric morphometrics in Morocco. Although it is present in all of Morocco, P. papatasi is the main vector of Leishmania major in only southern part of the Atlas Mountains. There are four major mountain ranges that serve as geographical barriers for species distribution in the study area and at least four gaps were recognized among these barriers. We found statistically significant differences in wing shape morphology between southern and northern populations. Analysis clearly recognized two main groups of populations on both sides of the mountains. The graphical depiction of Principal Component Analysis (PCA) and Canonical Variates Analysis (CVA) confirmed our morphometric study suggesting that the difference in wing morphology between the populations indicates that the population of P. papatasi shows phenotypic plasticity in the study area. According to centroid size analyses, which were used as measures of wing size differences among different sites, the north population of P. papatasi had relatively larger wings than the south population.     

Habitat fragmentation and body‐shape variation of African hind Cephalopholis taeniops (Valenciennes) in an archipelago system (Cape Verde,eastern Atlantic Ocean)

Morphological variations of the serranid fish Cephalopholis taeniops were studied in relation to habitat fragmentation in the Cape Verde Archipelago. While a significant allometric effect existed (11·5% of total body‐shape variation), differences in morphology associated with sex and ontogeny were not significant. MANOVA followed by CVA showed that each island presented a particular allometric pattern. Average body shape for all islands was well discriminated with CVA models. Pair‐wise comparisons of the ontogeny of morphological change between islands revealed that northern islands (Santo Antão, São Vicente and Santa Luzia) along with Boavista Island showed a similar direction in shape ontogeny, while all other paired comparisons indicated different ontogenetic patterns. When comparing directions of inter‐population shape changes, individuals from Fogo Island, the southernmost locality, departed far from the orthogonal relation, suggesting that they were undergoing independent body‐shape trajectories. Physical isolation by geographic distance and depth was positively correlated with morphological divergence among populations from different islands. This finding supports the hypothesis that habitat fragmentation in the Cape Verde Archipelago can be interpreted in terms of marine population structure.     

Geometric Morphometric Analysis of Body-Form Variability in Cichlasoma minckleyi, the Cuatro Cienegas cichlid

In this study, I investigate body-form variability in the trophically polymorphic Cuatro Cienegas cichlid, Cichlasoma minckleyi. I use geometric morphometrics to assess and compare size, shape, and allometric patterns within and between dental morphs (distinguished by differences in pharyngeal bones and papilliform or molariform dentitions). I find that dental morphs do not differ significantly in size, shape, or allometric slopes, but do differ in allometric intercepts; thus, dental morphs exhibit different patterns of body-form variability. Within each morph, body-form varies between more fusiform 'piscivores' and deeper-bodied dietary generalists. However, papilliform individuals show a continuous distribution of body-forms, whereas molariform individuals exhibit a discontinuity. I compare results from geometric analyses with those from a traditional (distance-based) morphometric analysis, finding that geometric techniques more clearly recognize discontinuities in shape. Finally, I suggest explanations for observed differences in body-form variability between dental morphs, concluding that the best explanation hinges on the relative importance of genetic and environmental factors in influencing body-form.