白额鹱卵壳的扫描电镜观察

本文报道白额鹱卵壳的壳膜、孔锥层、海绵层、表层等的超微结构,并对卵壳元素进行ＴＮ－５５００能谱分析。     

弄岗穗鹛卵壳的超微结构及部分元素组成的初步研究

为了解鸟类新种弄岗穗鹛卵壳的特征,利用扫描电镜对其卵壳进行了观察,并利用火焰原子吸收法和分光光度法对卵壳的部分元素成分进行了测量。结果显示弄岗穗鹛的卵壳厚约为(81.50±3.04)μm(n=30),从外向内依次分为4层:表面晶体层、栅栏层、锥体层和壳膜层。其中表面晶体层较为粗糙,有开放气孔分布;栅栏层结构紧密,是卵壳的主要构成部分,并遍布蜂窝状小孔;锥体层由锥体基层和乳锥层组成;壳膜层由多层直径约为(1.28±0.50)μm(n=30)蛋白质纤维组成。Ca是弄岗穗鹛卵壳的主要构成元素,含量达507.26mg/g,而Fe、Sr、Mn和Al为微量元素。弄岗穗鹛卵壳的特殊结构及元素组成可能是其对石灰岩生境及不擅长飞行的适应。     

藏马鸡卵壳的扫描电镜观察

利用扫描电镜对我国特有珍禽──藏马鸡的卵壳进行了超微结构观察。电镜下显示：藏马鸡卵壳从内向外由壳膜层、锥体层、海绵层和表层等组成。壳膜层内层致密、含少量纤维,外层为纵横交错成网状的纤维结构,锥体层由许多乳头状突起密集排列组成,海绵层为似沉积岩层的层状结构,表层在卵壳最外面,上由具保护性的透明蛋白质薄膜覆盖。与同属的褐马鸡的卵壳进行比较,其超微结构存在差异。     

丹顶鹤弃卵和正常卵卵壳超微结构及 化学元素含量的比较分析

为研究繁殖丹顶鹤（Grus japonensis）弃卵原因,对其弃卵与正常卵壳超微结构及化学元素含量进行比较。以2014至2020年在扎龙保护区收集到丹顶鹤弃卵和正常孵化的卵各6枚为研究对象,利用电子扫描电镜观察比较其超微结构,采用电感偶合等离子体光谱仪测量其化学元素含量,并对其卵壳厚度和密度进行测量和比较。弃卵壳厚度、密度分别为正常卵壳厚度、密度的68.0%(P <0.01)和71.5%(P <0.01);弃卵卵壳表面晶体层厚度不均,与栅栏层之间界限不明显,外表皮层有龟裂和条形两种裂纹,栅栏锥体层晶体中有微小球状中空结构和类似溶洞的腔室结构,壳膜层纤维表面的片状突起较少,这些结构均与正常卵壳不同。检测卵壳23种化学元素中,弃卵卵壳Ca、Na、P、Mg和K元素含量显著低于正常孵卵卵壳（P <0.05）。从卵壳结构和元素分析,卵壳元素含量异常、结构和功能缺陷有可能是导致其亲鸟弃卵的原因之一,这与亲鸟占据生境资源情况、与其他鸟类间繁殖压力、食物可获得性和生存对策等交互作用的影响有关。     

波斑鸨与大鸨卵壳的超微结构比较

利用扫描电镜对波斑鸨（Ｏｔｉｓ ｕｎｄｕｌａｔａ ｍａｃｑｕｅｅｎｉｉ）和大鸨（Ｏｔｉｓ ｔａｒｄａ ｔａｒｄａ）卵壳的壳膜层、锥体层、海绵层和表层的超微结构进行了比较研究。结果显示,作为同属鸟类,它们的外壳表面具有相似性,即均具有突起及大小不等的气孔,壳膜纤维交错成网状、海绵层分布有较多蜂窝小孔等。但作为不同的种,二者又具有显著差异,这种结构上的差异与种的特异性、成鸟的本重、卵的大小及生存环境密     

中国特产雉类—褐马鸡,藏马鸡和蓝马鸡卵壳的电镜观察

迄今为止,在国内有关野生鸟类卵壳的超微结构报道尚少。我们对中国特产鸡类——三种马鸡卵壳的表皮、气孔、木栅层、锥体层、乳头结、壳膜和基帽进行了扫描巨镜观察,并对结果进行了比较、讨论。认为三种马鸡不同结构的形态,对研究它们的亲缘关系提供了新的价值。     

略谈鸟卵壳

每种鸟所产的卵的卵壳在形态、结构和组成成分等方面都有较稳定的特异性。卵壳能为研究鸟的系统分类、演化和地理分布等提供有价值的科学资料。本文扼要地介绍了卵壳的超微结构——壳膜、乳头层、海绵层、护膜和气孔道等结构和功能。     

卵壳超微结构观测去内膜新方法

在对鸟类卵壳超微结构进行研究时 ,卵壳内表面有一层极薄而且坚韧的内膜很难除去 ,现阶段唯一的方法是用小镊子在实体显微镜下剥离。但由于内膜纤维深入乳锥 ,与乳锥之间的纤维交织在一起 ,且长入乳突内 ,使膜与卵壳紧密结合 ,常常剥离不下来。我们在进行卵壳超微结构研究时 ,用蛋白酶溶解卵壳内膜 ,获得了很好的结果。1　材料与方法取新鲜鸡蛋蛋壳 ,蛋白酶Ｋ。将 10ｍｇ蛋白酶Ｋ溶于 1ｍｌ灭菌Ｈ2 Ｏ中 ,按 2 0 0 μｌ分装贮存于 - 2 0℃。配制组织提取液 10 0ｍｌ:1ｍｏｌ ＬＴｒｉｓ ｃｌ(ｐＨ8.0 ) 5ｍｌ;0 5ｍｏｌ ＬＥＤＴＡ (ｐＨ8.…     

纵纹腹小、鵰及长耳的卵壳超微结构研究（形目：鸱科）

本文首次报道纵纹腹小、、长耳卵壳的气孔、木栅层、锥体层、乳锥体、壳膜、基底帽等结构的扫描电镜观察,并对不同种类进行分析,初步探讨了它们的分类价值和生态意义。     

朱鹮卵壳的微观结构和成分研究

本文首次对世界珍禽——朱鹮的卵壳在电子显微镜下的微观结构进行了研究;对卵壳中的26种无机元素进行了定量分析。根据两巢卵壳所含有害元素的对比,以及两巢区土壤中有害元素含量对照情况,指出保护朱鹮自然种群、研究其环境因子,刻不容缓。     

Palaeoenvironmental reconstruction of dinosaur nesting sites based on a geochemical approach to eggshells and associated palaeosols (Maastrichtian, Provence Basin, France)

Variability of the stable isotopic (δ¹³C and δ¹⁸O) and trace element (Mg, Sr, Fe, and Mn) content from dinosaur eggshells from the Provence Basin has been addressed by considering the stratigraphic distribution of the eggshells, the palaeoenvironments, and the chemical content of associated sediments. Preferentially, in situ eggshells were analysed. Samples were collected from two sections, one belonging to the floodplain (Roques Hautes) and the other to the channel belt (Rousset-Bréguières), as determined from sedimentological criteria. On a regional scale, this combined analysis provided new insights into palaeohydrology, vegetation cover and dinosaur behaviour. Different sources of drinking water were identified: (1) the main stream waters with significant salinity levels, (2) lateral feeders with water composition close to that of precipitation. Water composition is reflected in the eggshell trace element contents: a high Sr content for the eggshells from the channel belt (mean 1200 ppm) contrasting with the very low values for the floodplain (mean 250 ppm). During the first part of the Maastrichtian, evaporation rates were quite significant, as seen from the 1.5‰ difference between the eggshell δ¹⁸O (drinking water) and the palaeosol carbonate nodules (precipitation). This contrast diminished and became nearly insignificant in the second half of the Maastrichtian. Vegetation was composed of C₃ plants and two ecosystems are reconstructed: a riparian forest extending along the channel belt and open vegetation in the floodplain. The contrasted isotopic and trace element content of the eggshells was a crucial factor in identifying animal migration from one site to another. Migration was quite limited, suggesting that the animals settled for some time at the places where they laid their eggs. Intraspecific variations among modern birds are well correlated with the environment and may be greater than interspecies variations, which limits the potential of geochemical analysis to characterise dinosaur species.     

Eggshell pigment composition covaries with phylogeny but not with life history or with nesting ecology traits of British passerines

No single hypothesis is likely to explain the diversity in eggshell coloration and patterning across birds, suggesting that eggshell appearance is most likely to have evolved to fulfill many nonexclusive functions. By controlling for nonindependent phylogenetic associations between related species, we describe this diversity using museum eggshells of 71 British breeding passerine species to examine how eggshell pigment composition and concentrations vary with phylogeny and with life‐history and nesting ecology traits. Across species, concentrations of biliverdin and protoporphyrin, the two main pigments found in eggshells, were strongly and positively correlated, and both pigments strongly covaried with phylogenetic relatedness. Controlling for phylogeny, cavity‐nesting species laid eggs with lower protoporphyrin concentrations in the shell, while higher biliverdin concentrations were associated with thicker eggshells for species of all nest types. Overall, these relationships between eggshell pigment concentrations and the biology of passerines are similar to those previously found in nonpasserine eggs, and imply that phylogenetic dependence must be considered across the class in further explanations of the functional significance of avian eggshell coloration.     

Scanning Microfocus Small Angle X-ray Scattering Study of the Avian Eggshell

Synchrotron microfocus small angle X-ray scattering was used to investigate the nanostructure and microscopic variation of eggshells. It uses a microbeam allowing the ability to probe interactions between the organic and inorganic components at nanometer level and is ideal for mapping over small areas to obtain a detailed analysis of structural variations. Thin sections of eggshells were scanned from the shell membrane （inner） to the cuticle （outer） surface. The data collected was used to produce two-dimensional maps showing microscopic changes within the different layers of the eggshell. The structural alterations ap- parently could have implications at the macroscopic level of the resulting eggshell. As the organic matrix is embedded within the eggshell this may contribute to the variations observed in calcite crystal form and texture, Structural information obtained about a biomaterial at different length scales is important in relating the structure to its functional properties. This knowledge and the principles behind the formation of biomaterials could be used in the attempt of bioengineering new systems.     

Fossile Reptil-Eischalen (Chelonia,Crocodilia, Dinosauria) aus dem unteren Barremium von Galve (Provinz Teruel,SE-Spanien)

The Lower Cretaceous vertebrate bearing sediments of Galve (province of Teruel, SE Spain) have yielded some hundred fossil eggshell fragments, all slightly diagenetically altered. Concerning their microstructure, an assignment of the material to different taxa of reptiles was possible. The eggshell assemblage of Galve consists of a-c) three types of chelonian eggshells, one of them probably representing the subfamily Batagurinae, which would extend this taxon back into the Lower Cretaceous, d) the oldest known crocodilian eggshells, with lacunae systems on the outer surface, comparable to Recent taxa, and e-f) two different types of dinosaurian eggshells. In correspondence to the suggested fluviatile paleoenvironment of Galve, the fossil eggshells described herein are fragmented and represent mostly turtles and crocodiles.     

Parents, predators, parasites, and the evolution of eggshell colour in open nesting birds

The colourful surface of birds’ eggshells varies dramatically between species, but the selective pressures driving this variation remain poorly understood. We used a large comparative dataset to test several hypotheses proposed to explain the evolution of eggshell colouration. We tested the hypothesis that predation pressure might select for cryptic eggshells by examining the relationship between predation rate and egg colouration. We found that predation rates were positively related to eggshell brightness. The blackmail hypothesis suggests that females lay colourful eggshells to coerce males into providing additional care during incubation to keep colourful eggs covered. According to this hypothesis, conspicuous eggs should be found in situations with high risk of visual detection from predators or brood parasites. In support of this hypothesis, proportional blue-green chroma was positively related to parasitism risk, and eggs with higher proportional blue-green chroma or higher ultraviolet chroma received higher combined parental nest attendance during the incubation period. The sexual signalling hypothesis states that blue-green colour indicates female quality; however, we did not find that blue-green eggshell colour was greater in species where males participate in any form of parental care, and relative male provisioning was unrelated to blue-green eggshell chroma. We found some support for the hypothesis that brood parasitism may select for high inter-clutch variation in eggshell colour to facilitate egg recognition. In our dataset, parasitism risk was negatively related to inter-clutch repeatability of blue-green chroma. Our study highlights the diversity of selection pressures acting on the evolution of eggshell colour in birds and provides suggestions for novel areas of future key research direction.     

Great spotted cuckoo eggshell microstructure characteristics can make eggs stronger

Obligate avian brood parasites lay stronger eggs than their hosts or non‐parasitic relatives because they are rounder and have a thicker eggshell. Additionally, some other characteristics of the brood parasitic eggshells related to their microstructure such as size and orientation of calcite crystal units could also contribute to generating even stronger shells. An eggshell microstructure formed by small randomly oriented calcite crystal units can increase the robustness of the eggshells of birds. Here, the eggshell microstructure of avian brood parasites as well as their hosts have been characterized in detail, using X‐ray diffraction analyses to estimate the size and degree of orientation of calcite crystal units making the eggshell. Specifically, the brood parasitic great spotted cuckoo Clamator glandarius and two hosts (jackdaws Corvus monedula and magpie Pica pica) and one non‐host species (the pigeon, Columba livia domestica) were considered. Calcite crystal of the eggshell of the brood parasitic species was smaller and more randomly oriented than those of the eggshells of non‐parasitic species, which suggest that eggshell microstructure would contribute to explain why parasitic eggs are more resistant to breakage than those of their hosts.     

卵壳的超微结构特征

本文运用扫描电镜研究了美洲鸵鸟,鹂鹋,非洲鸵鸟,普通家鸡,环颈雉,绿头鸭,王企鹅等七种现生鸟蛋壳和更新世安氏鸵鸟蛋壳以及六种白垩纪恐龙蛋壳（长形长形蛋Ｅｌｏｎｇａｔｏｏｌｉｔｈｕｓｅｌｏｎｇａｔｕｓ,安氏长形蛋Ｅｌｏｎｇａｔｏｏｌｉｔｈｕｓａｎｄｒｅｗｓｉ,瑶屯巨形蛋Ｍａｃｒｏｏｌｉｔｈｕｓｙａｏｔｕｎｅｎｓｉｓ粗皮巨形蛋Ｍａｃｒｏｏｌｉｔｈｕｓｒｕｇｕｓｔｕｓ,将军顶圆形蛋Ｓｐｈｅｒｏｏｌｉｔｈ     

Eggshell Types and Their Evolutionary Correlation with Life-History Strategies in Squamates

The eggshell is an important physiological structure for the embryo. It enables gas exchange, physical protection and is a calcium reserve. Most squamates (lizards, snakes, worm lizards) lay parchment-shelled eggs, whereas only some gekkotan species, a subgroup of lizards, have strongly calcified eggshells. In viviparous (live-bearing) squamates the eggshell is reduced or completely missing (hereafter “shell-less”). Recent studies showed that life-history strategies of gekkotan species differ between species with parchment- and rigid-shelled eggshells. Here we test if the three different eggshell types found in the squamates are also associated with different life-history strategies. We first investigated the influence of the phylogeny on the trait “eggshell type” and on six life-history traits of 32 squamate species. Phylogenetic principal component analysis (pPCA) was then conducted to identify an association between life-history strategies and eggshell types. Finally, we also considered adult weight in the pPCA to examine its potential effect on this association. Eggshell types in squamates show a strong phylogenetic signal at a low taxonomical level. Four out of the six life-history traits showed also a phylogenetic signal (birth size, clutch size, clutches per year and age at female maturity), while two had none (incubation time, maximum longevity). The pPCA suggested an association of life-history strategies and eggshell types, which disappeared when adult weight was included in the analysis. We conclude that the variability seen in eggshell types of squamates is weakly influenced by phylogeny. Eggshell types correlate with different life-history strategies, and mainly reflect differences in adult weights of species.