Niche divergence

  • 文章类型: Journal Article
    波斯小鹿或美索不达米亚小鹿(DamaMesopotamica,布鲁克1875),具有重要生态意义的物种,在伊朗面临灭绝的威胁。一种保护策略涉及将波斯鹿转移到伊朗各地的封闭地区,在那里,他们得到了免受外部威胁的保护,并得到了人类看护者的基本护理。当人类看护者努力满足他们的需求并减轻外部威胁时,气候变量现在可能成为影响封闭地区人口动态的关键因素。这项研究旨在评估波斯鹿种的原始区域(Dez和Karkheh)与11个新封闭区域之间的气候生态位相似性。为了实现这一点,我们使用气候数据和生态位建模(ENM)技术来评估12个地区之间的气候变化。我们利用环境等效性测试来确定区域对的环境空间是否表现出显着差异,以及这些空间是否可以互换。在接下来的步骤中,还进行了外推分析,以探索与伊朗其他地区不相似的原始休耕鹿栖息地的气候条件。我们的结果揭示了原始地区和所有易位地区之间的气候条件存在显着差异。根据对特定封闭地区人口增长的观察,在这些地区,易位的鹿种群蓬勃发展,我们假设该物种可能在伊朗表现出非平衡分布。因此,这些新的区域可能被视为该物种潜在气候生态位的一部分。外推分析表明,对于伊朗的很大一部分,外推预测对于波斯休养鹿的易位是高度不确定的,并且可能不可靠。然而,迁移努力的主要目标仍然是建立能够在封闭区域以外的自然区域繁荣发展的自我维持的波斯鹿种群,从而确保它们的长期生存,并有助于保护工作。评估新易位物种的成功需要额外的时间,观察到不同程度的成功。在某些封闭地区的物种生长速度低于预期的情况下,谨慎考虑可能导致人口减少的气候变量。此外,为了未来的易位,我们建议选择与该物种表现出增长率的地区气候相似的地区。
    The Persian fallow deer or Mesopotamian fallow Deer (Dama mesopotamica, Brook 1875), a species of significant ecological importance, had faced the threat of extinction in Iran. One conservation strategy involved the translocation of Persian deer to enclosed areas across Iran, where they were afforded protection from external threats and provided with essential care by human caretakers. While human caretakers diligently attend to their needs and mitigate external threats, climate variables may now become critical factors affecting population dynamics in enclosed areas. This study aims to assess the similarity in climate niches between the original area (Dez and Karkheh) of the Persian deer species and 11 newly enclosed areas. To achieve this, we employed climate data and ecological niche modeling (ENM) techniques to assess the variations in climate among 12 areas. We utilized the environmental equivalency test to determine whether the environmental spaces of area pairs exhibit significant differences and whether these spaces are interchangeable. Extrapolation analyses were also constructed in the next steps to explore climatic conditions in original fallow deer habitats that are non-analogous to those in other parts of Iran. Our results reveal significant disparities in climate conditions between the original and all translocated areas. Based on observations of population growth in specific enclosed areas where translocated deer populations have thrived, we hypothesize that the species may demonstrate a non-equilibrium distribution in Iran. Consequently, these new areas could potentially be regarded as part of the species\' potential climate niche. Extrapolation analysis showed that for a significant portion of Iran, extrapolation predictions are highly uncertain and potentially unreliable for the translocation of Persian fallow deer. However, the primary objective of translocation efforts remains the establishment of self-sustaining populations of Persian deer capable of thriving in natural areas beyond enclosed areas, thus ensuring their long-term survival and contributing to preservation efforts. Evaluating the success of newly translocated species requires additional time, with varying levels of success observed. In cases where the growth rate of the species in certain enclosed areas falls below expectations, it is prudent to consider climate variables that may contribute to population declines. Furthermore, for future translocations, we recommend selecting areas with climate similarities to regions where the species has demonstrated growth rates.
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  • 文章类型: Journal Article
    通过整合物种分布建模技术,系统发育比较方法,和气候数据,我们分析了欧洲猎鹰气候生态位随着进化时间的变化,以了解它们的节奏和进化模式,并获得与猎鹰进化的生态环境相关的系统发育见解。为此,我们测试了利基保守主义的相对贡献,趋同进化,以及欧洲这组物种的进化史上的不同进化。欧洲猎鹰物种对气候生态位空间的占用并不相似,考虑到它们的气候生态位演变具有异位性,尤其是在CA之后.4Mya.我们的结果表明,趋同进化和生态位差异在这些物种的进化史中起着重要作用。没有明显的证据表明密切相关的物种会随着时间的推移保留其基本生态位(系统发育生态位保守主义)。在大多数分析中,不太密切相关的猎鹰物种占据了相似的气候环境。我们发现,欧洲属Falco的物种形成受到气候生态位分化的影响,在过去的400万年里更加普遍,主要的气候生态位变化发生在密切相关的猎鹰物种之间。
    By integrating species distribution modeling techniques, phylogenetic comparative methods, and climatic data, we analyzed how European falcon climatic niches have changed over evolutionary time in order to understand their tempo and mode of evolution and gain phylogenetic insights related to the ecological context of falcon evolution. For this purpose, we tested the relative contributions of niche conservatism, convergent evolution, and divergent evolution in the evolutionary history of this group of species in Europe. The occupation of climatic niche spaces by falcon species in Europe was not similar, considering that their climatic niche evolution was characterized by heterotachy, especially after ca. 4 Mya. Our results indicate that convergent evolution and niche divergence played an important role in the evolutionary history of these species, with no significant evidence of closely related species retaining their fundamental niche over time (phylogenetic niche conservatism). In most analyses, less closely related falcon species occupied similar climatic environments. We found that speciation in the European genus Falco was influenced by climatic niche differentiation, more prevalent in the last 4 million years, with the main climatic niche shifts occurring between closely related falcon species.
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  • 文章类型: Journal Article
    生殖障碍的进化,也就是说,物种形成过程,意味着种群之间基因流动的局限性。在整个物种形成连续体中,基因组分化的不同模式可能会提供对物种分化的因果进化力的见解。在这项研究中,我们分析了Hetaerina属(Odonata)的隐秘物种复合体。这个复合体包括H.americana和H.calverti;然而,在美洲汉堡包中,先前已经检测到两个高度分化的遗传组,which,我们假设,可能对应于具有低形态变异的不同物种。我们获得了90个个体的单核苷酸多态性(SNP)数据,这些个体属于复合物中的不同分类单元,并进行了分化测试以鉴定遗传分离。主成分结构和判别分析(DAPC)的结果,基于近5000个SNP,证实了三个高度分化的分类单元的存在。此外,我们在成对比较中发现FST值高于0.5,这表明建议物种之间存在相当大的遗传隔离。我们还发现所有分类群之间的气候生态位重叠较低,这表明每一组都发生在特定的温度条件下,降水和海拔。我们建议美洲H.Americana包含两个神秘物种,它们可能被与生态位发散相关的生态屏障生殖隔离,由于形态变异最小,因此,与其他相关物种如H.calverti相比,机械屏障可能不太有效。
    The evolution of reproductive barriers, that is, the speciation process, implies the limitation of gene flow between populations. Different patterns of genomic differentiation throughout the speciation continuum may provide insights into the causal evolutionary forces of species divergence. In this study, we analysed a cryptic species complex of the genus Hetaerina (Odonata). This complex includes H. americana and H. calverti; however, in H. americana two highly differentiated genetic groups have been previously detected, which, we hypothesize, may correspond to different species with low morphological variation. We obtained single nucleotide polymorphism (SNP) data for 90 individuals belonging to the different taxa in the complex and carried out differentiation tests to identify genetic isolation. The results from STRUCTURE and discriminant analysis of principal components (DAPC), based on almost 5000 SNPs, confirmed the presence of three highly differentiated taxa. Also, we found FST values above 0.5 in pairwise comparisons, which indicates a considerable degree of genetic isolation among the suggested species. We also found low climatic niche overlap among all taxa, suggesting that each group occurs at specific conditions of temperature, precipitation and elevation. We propose that H. americana comprises two cryptic species, which may be reproductively isolated by ecological barriers related to niche divergence, since the morphological variation is minimal and, therefore, mechanical barriers are probably less effective compared to other related species such as H. calverti.
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  • 文章类型: Journal Article
    功能性状是决定生长的形态和生理特征,繁殖,和生存策略。叶子经济学提出了两种相反的生活史策略:具有“获取性”策略的物种快速增长并利用高资源环境,而具有“保守”策略的物种强调在低资源条件下的生存和缓慢生长。我们分析了来自林下和冠层的7个新热带棕榈物种中与生物量分配和组织质量相关的9个功能性状的种内和种间变异。我们预计,一个物种通常利用的地层资源水平将决定剥削性或保守性策略的主导地位,以及物种之间功能性状的差异程度。如果这是正确的,然后冠层物种将表现出一种获取策略,强调以更大尺寸为目标的性状,而林下物种将表现出保守的策略,其性状可促进有效的生物量分配和在阴凉处的生存。两个主成分(变异的57.22%)将棕榈物种分为:(a)冠层物种,其特征与获取策略一致并强调大尺寸(即,直径,高度,碳含量,和叶面积),和(B)特征与有效生物量分配相关的林下物种(即,干质量分数-DMF-和组织密度)。当我们解开手掌功能特征的变异时,占热带植物的很大比例,我们对植物如何适应环境梯度有了更深入的了解。
    Functional traits are morphological and physiological characteristics that determine growth, reproduction, and survival strategies. The leaf economics spectrum proposes two opposing life history strategies: species with an \"acquisitive\" strategy grow fast and exploit high-resource environments, while species with a \"conservative\" strategy emphasize survival and slow growth under low resource conditions. We analyzed intra and interspecific variation in nine functional traits related to biomass allocation and tissue quality in seven Neotropical palm species from understory and canopy strata. We expected that the level of resources of a stratum that a species typically exploits would determine the dominance of either the exploitative or conservative strategy, as well as degree of divergence in functional traits between species. If this is correct, then canopy species will show an acquisitive strategy emphasizing traits targeting a larger size, whereas understory species will show a conservative strategy with traits promoting efficient biomass allocation and survival in the shade. Two principal components (57.22% of the variation) separated palm species into: (a) canopy species whose traits were congruent with the acquisitive strategy and emphasized large size (i.e., diameter, height, carbon content, and leaf area), and (b) understory species whose traits were associated with efficient biomass allocation (i.e., dry mass fraction -DMF- and tissue density). As we unravel the variation in functional traits in palms, which make up a substantial proportion of the tropical flora, we gain a deeper understanding of how plants adapt to environmental gradients.
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  • 文章类型: Journal Article
    大小和形状上的性二态性在鳞类爬行动物中普遍存在。蛇头骨大小和形状的性别差异通常伴随着双性恋进食小生境的分离。然而,这些差异背后的异速轨迹在几个谱系中仍未研究。海kraitLaticaudacolubrina(蛇纹石:Elapidae)在体型上表现出非常明显的性二态性,以前的研究报告说女性更大,头部相对更长更宽。这两种性别的摄食习惯也不同:雄性倾向于在浅水中捕食,而雌性则在更深的水中捕食盘条鳗鱼。
    我调查了头骨形状和大小以及头骨生长模式的性二态性,以确定男性和女性是否遵循相同的个体发育轨迹。我研究了61名男性和女性海krait的头骨特征和身体长度。
    头骨形状不同。雄性和雌性遵循不同的异速运动轨迹。与喂养性能相关的结构偏向女性,而头端和眶区偏向男性。两种性别的进食相关结构(女性偏向)的异速轨迹不同,这与性别之间的饮食差异相对应。
    Seakraits在头骨形式中表现出明显的性二态性,这可以通过饮食习惯和生殖角色的性交差异来解释。整体头骨生长模式类似于在其他四足动物中观察到的典型模式。
    Sexual dimorphism in size and shape is widespread among squamate reptiles. Sex differences in snake skull size and shape are often accompanied by intersexual feeding niche separation. However, allometric trajectories underlying these differences remain largely unstudied in several lineages. The sea krait Laticauda colubrina (Serpentes: Elapidae) exhibits very clear sexual dimorphism in body size, with previous studies having reported females to be larger and to have a relatively longer and wider head. The two sexes also differ in feeding habits: males tend to prey in shallow water on muraenid eels, whereas females prey in deeper water on congerid eels.
    I investigated sexual dimorphism in skull shape and size as well as the pattern of skull growth, to determine whether males and females follow the same ontogenetic trajectories. I studied skull characteristics and body length in 61 male and female sea kraits.
    The sexes differ in skull shape. Males and females follow distinct allometric trajectories. Structures associated with feeding performance are female-biased, whereas rostral and orbital regions are male-biased. The two sexes differ in allometric trajectories of feeding-related structures (female biased) that correspond to dietary divergence between the sexes.
    Sea kraits exhibit clear sexual dimorphism in the skull form that may be explained by intersexual differences in the feeding habits as well as reproductive roles. The overall skull growth pattern resembles the typical pattern observed in other tetrapods.
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  • 文章类型: Journal Article
    被子植物,白垩纪陆地革命(KTR)的导火索,经历了快速扩张,并在上白垩纪中段占据了所有环境。然而,北半球被子植物多样性分布的白垩纪生物地理格局和过程仍然鲜为人知。这里,我们阐明了被子植物科罂粟科的生物地理多样性,一种古老的北半球进化枝,其特征是传播能力差和高度的区域特有性。基于质体和多位点数据集,我们重建了一个强大的时间校准系统发育,其中包括该家族的所有目前公认的45属。在时间校准的系统发育框架内,我们通过测试区域划界不确定度的敏感性进行了72次生物地理分析,maxarea约束,和模型的参数,即,j(描述跳跃-分散事件)和w(修改分散乘数矩阵),祖先范围估计。我们还推断了祖先的栖息地和生态位。系统发育分析强烈支持罂粟科为单系。蕨类植物被大力支持为Hypcoideae-Fumarioideae的姐妹。我们的结果表明,j参数和预定义区域的数量强烈影响祖先范围估计,产生可疑的祖先范围,而maxarea约束和w参数没有影响,提高了模型拟合。在考虑了这些不确定性之后,我们的结果表明,罂粟科在下白垩纪期间在亚洲湿林中分化,随后占领了亚洲和北美西部的干旱和开放地区。在白垩纪中上游发生了三次从亚洲通过白令陆桥扩散到北美西部,在很大程度上与KTR一致。生境转移和生态位差异导致亚洲和北美西部之间随后的分离。这些发现表明,范围扩展和生态位发散驱动的代位权的相互作用可能已经塑造了北半球具有罂粟科样生态要求和扩散能力的被子植物的白垩纪生物地理模式,因此有助于了解KTR期间被子植物的地理扩展。
    Angiosperms, a trigger for the Cretaceous Terrestrial Revolution (KTR), underwent a rapid expansion and occupied all the environments during the Mid-Upper Cretaceous. Yet, Cretaceous biogeographic patterns and processes underlying the distribution of angiosperm diversity in the Northern Hemisphere are still poorly known. Here, we elucidated the biogeographic diversification of the angiosperm family Papaveraceae, an ancient Northern Hemisphere clade characterized by poor dispersal ability and high level of regional endemism. Based on both plastome and multi-locus datasets, we reconstructed a robust time-calibrated phylogeny that includes all currently recognized 45 genera of this family. Within the time-calibrated phylogenetic framework, we conducted 72 biogeographic analyses by testing the sensitivity of uncertainties of area delimitation, maxarea constraints, and the parameters of the model, i.e., j (describing jump-dispersal events) and w (modifying dispersal multiplier matrices), to ancestral range estimations. We also inferred ancestral habitat and ecological niches. Phylogenetic analyses strongly support Papaveraceae as monophyletic. Pteridophylloideae is strongly supported as sister to Hypecoideae-Fumarioideae. Our results indicate that the j parameter and number of predefined areas strongly affect ancestral range estimates, generating questionable ancestral ranges, whereas maxarea constraint and w parameter have no effect and improve model fit. After accounting for these uncertainties, our results indicate that Papaveraceae differentiated in Asian wet forests during the Lower Cretaceous and subsequently occupied the Asian and western North American arid and open areas. Three dispersals from Asia to western North America via the Bering land bridge occurred in the Mid-Upper Cretaceous, largely in agreement with the KTR. Habitat shift and ecological niche divergence resulted in the subsequent disjunctions between Asia and western North America. These findings suggest that the interplay of range expansion and niche divergence-driven vicariance might have shaped Cretaceous biogeographic patterns of angiosperms with Papaveraceae-like ecological requirements and dispersal abilities in the Northern Hemisphere, hence contributing to the knowledge on the geographic expansion of angiosperms during the KTR.
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  • 文章类型: Journal Article
    当植物谱系进入祖先传粉者较不常见的新栖息地时,传粉者可能会发生转换,一种新颖的传粉者更常见。因为传粉者社区根据环境耐受性和资源的可用性而有所不同,授粉模式与特定区域和栖息地之间可能存在一致的关联。可以在经历过多个传粉媒介转变的谱系中研究这种关联,代表进化复制。
    我们的研究集中在北美西部的一个大进化枝Penstemon野花物种,它一再从祖先的蜜蜂适应花进化出适应蜂鸟的花。对于每个物种,我们从发生数据估计地理范围,从气候推断环境生态位,地形,土壤数据。使用系统发育比较方法,我们调查了适应蜂鸟的物种相对于适应蜂鸟的物种是否占据不同的地理区域或栖息地。
    蜂鸟适应的物种比蜜蜂适应的物种出现在较低的纬度和较低的海拔,导致他们的环境生态位不同。在相对较低的海拔和纬度地区也发现了适应蜜蜂的物种与适应蜂鸟的物种姐妹,类似于它们适应蜂鸟的姐妹物种,表明生态地理变化先于传粉者发散。姐妹物种对-无论它们在传粉媒介上是否不同-显示出相对较小的地理范围重叠。
    对新型传粉媒介的适应通常发生在与祖先种群的地理和生态隔离中。给定血统适应新型传粉者的能力可能严重取决于其在与新型传粉者群落相关的区域和栖息地中定居的能力。
    A switch in pollinator can occur when a plant lineage enters a new habitat where the ancestral pollinator is less common, and a novel pollinator is more common. Because pollinator communities vary according to environmental tolerances and availability of resources, there may be consistent associations between pollination mode and specific regions and habitats. Such associations can be studied in lineages that have experienced multiple pollinator transitions, representing evolutionary replicates.
    Our study focused on a large clade of Penstemon wildflower species in western North America, which has repeatedly evolved hummingbird-adapted flowers from ancestral bee-adapted flowers. For each species, we estimated geographic ranges from occurrence data and inferred environmental niches from climate, topographical, and soil data. Using a phylogenetic comparative approach, we investigated whether hummingbird-adapted species occupy distinct geographic regions or habitats relative to bee-adapted species.
    Hummingbird-adapted species occur at lower latitudes and lower elevations than bee-adapted species, resulting in a difference in their environmental niche. Bee-adapted species sister to hummingbird-adapted species are also found in relatively low elevations and latitudes, similar to their hummingbird-adapted sister species, suggesting ecogeographic shifts precede pollinator divergence. Sister species pairs-regardless of whether they differ in pollinator-show relatively little geographic range overlap.
    Adaptation to a novel pollinator may often occur in geographic and ecological isolation from ancestral populations. The ability of a given lineage to adapt to novel pollinators may critically depend on its ability to colonize regions and habitats associated with novel pollinator communities.
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  • 文章类型: Journal Article
    后生动物拥有复杂的微生物群落,包括鞭毛藻,真菌,细菌,古细菌和病毒。这些复杂组合的成员之间的相互作用使宿主能够调整其生理和新陈代谢以应对环境变化并占据不同的栖息地。这里,使用跨深度的相互移植,我们研究了珊瑚的适应性发散,两个年轻的物种,在加勒比海具有相反的垂直分布。当从深到浅移植时,O.franksi经历了快速的光适应和低死亡率,并保持了一致的细菌群落。相比之下,O.从浅到深移植时,环状体的死亡率很高,光适应有限。深部环境中环状O的光生理塌陷与微生物组变异性增加和某些细菌类群减少有关。珊瑚物种之间的共生藻类群落差异比深度之间更为明显。我们的研究表明,这些兄弟姐妹物种适应了独特的光环境,部分由藻类的光驯化能力和微生物组的鲁棒性驱动,强调共生珊瑚生态位专业化对维持物种多样性的重要性。我们的发现对这些受威胁的加勒比珊瑚的管理以及珊瑚礁恢复工作的有效性具有重要意义。
    Metazoans host complex communities of microorganisms that include dinoflagellates, fungi, bacteria, archaea and viruses. Interactions among members of these complex assemblages allow hosts to adjust their physiology and metabolism to cope with environmental variation and occupy different habitats. Here, using reciprocal transplantation across depths, we studied adaptive divergence in the corals Orbicella annularis and O. franksi, two young species with contrasting vertical distribution in the Caribbean. When transplanted from deep to shallow, O. franksi experienced fast photoacclimation and low mortality, and maintained a consistent bacterial community. By contrast, O. annularis experienced high mortality and limited photoacclimation when transplanted from shallow to deep. The photophysiological collapse of O. annularis in the deep environment was associated with an increased microbiome variability and reduction of some bacterial taxa. Differences in the symbiotic algal community were more pronounced between coral species than between depths. Our study suggests that these sibling species are adapted to distinctive light environments partially driven by the algae photoacclimation capacity and the microbiome robustness, highlighting the importance of niche specialization in symbiotic corals for the maintenance of species diversity. Our findings have implications for the management of these threatened Caribbean corals and the effectiveness of coral reef restoration efforts.
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  • 文章类型: Journal Article
    在季节性干燥的热带森林(SDTF)中,对南美生物多样性的进化史研究甚少。这个生态系统中的物种多样化可能有双重解释。首先,更新世中晚期的间歇性连接促进了物种的扩散和/或在森林分离斑块中分离的谱系之间的遗传连接。第二,SDTF在新近纪中形成和定殖后,立即进行了同种异体物种形成。在这里,我们研究了Psammolestes的多样化,SDTF属,自然感染克氏锥虫(恰加斯病的病原体),使用系统发育的组合,种群遗传学和生态位模型方法,并评估了目前公认的三种形态物种的可靠性。
    我们的多位点分析恢复了P.arthuri的单系进化枝姐妹中的P.coreodes和P.tertius。尽管在五个基因中观察到P.coreodes和P.tertius之间存在共同的遗传变异,但物种定界测试将这些谱系恢复为不同的物种。此外,该属的遗传变异集中在与三个形态种一致的三个群体中。我们的人口统计学模型预测了没有基因流动的情况下的分歧,这表明混合单倍型可能是由于亚热带温带物种P.coreodes和P.tertius的分歧而导致的共同祖先变异的结果。相比之下,在所有遗传结构测试中,热带物种arthuri与其他两个物种高度不同,并且始终如一,Monmonier的算法确定了一个清晰的地理屏障,将该物种与P.corodes和P.tertius分开。
    我们在Psammolestes中发现了三个遗传结构的谱系,这些谱系在上世纪晚期没有基因流的情况下发生了分歧。该结果支持了由地理隔离而不是面对与更新世气候振荡相关的基因流动的分歧所驱动的物种形成的情景。此外,我们认为亚马逊盆地是将热带和亚热带温带物种分开的气候屏障,从而促进远距离分散后的异方形态形成。最后,Psammolestes的每个物种占据不同的气候生态位,这表明生态位保守主义对于物种分化并不重要。这些发现影响了该地区当前的查加斯病媒介监测计划。
    The evolutionary history of biodiversity in South America has been poorly studied in the seasonal dry tropical forest (SDTF). Species diversification in this ecosystem may have a twofold explanation. First, intermittent connections in the middle and late Pleistocene promoted species dispersal and/or genetic connectivity between lineages isolated in disjunct patches of forest. Second, allopatric speciation proceeded immediately after the formation and colonization of the SDTF in the Neogene. Here we studied the diversification of Psammolestes, a genus endemic of the SDTF and naturally infected with Trypanosoma cruzi (agent of Chagas disease), using a combination of phylogenetic, population genetics and niche model methods, and evaluated the reliability of the three morphospecies currently recognized.
    Our multilocus analyses recovered P. coreodes and P. tertius in a monophyletic clade sister to P. arthuri. Species delimitation tests recovered these lineages as different species despite the shared genetic variation observed between P. coreodes and P. tertius in five genes. Also, genetic variation of the genus clustered in three groups that were consistent with the three morphospecies. Our demographic model predicted a scenario of divergence in absence of gene flow, suggesting that mixed haplotypes may be the result of shared ancestral variation since the divergence of the subtropical-temperate species P. coreodes and P. tertius. In contrast, the tropical species P. arthuri was highly differentiated from the other two in all tests of genetic structure, and consistently, the Monmonier\'s algorithm identified a clear geographical barrier that separates this species from P. coreodes and P. tertius.
    We found three genetically structured lineages within Psammolestes that diverged in absence of gene flow in the late Miocene. This result supports a scenario of species formation driven by geographical isolation rather than by divergence in the face of gene flow associated with climatic oscillations in the Pleistocene. Also, we identified the Amazon basin as a climatic barrier that separates tropical from subtropical-temperate species, thus promoting allopatric speciation after long range dispersion. Finally, each species of Psammolestes occupies different climatic niches suggesting that niche conservatism is not crucial for species differentiation. These findings influence the current vector surveillance programs of Chagas disease in the region.
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  • 文章类型: Journal Article
    性别特异性表型差异在整个动物界普遍存在。性状差异提供的生殖优势是有代价的。这里,我们将性别特异性觅食策略与性别二态北象海豹(Miroungaangustirostris)觅食奖励和死亡风险之间的权衡联系起来.我们分析了运动模式的十年数据集,潜水行为,觅食成功率和死亡率。雌性是公海栖息地中的深海捕食者。雄性是大陆架栖息地中的浅层潜水底栖捕食者。男性的体重增加了6倍,获得能量的速度是女性的4.1倍。高觅食成功率伴随着高死亡率。男性死亡的可能性是女性的六倍。这些觅食策略和权衡与不同的能源需求和生活史策略有关。雄性使用高死亡率的觅食策略来获得争夺雌性所需的大体型,作为有史以来最大的雄性的一小部分。雌性使用死亡率较低的觅食策略,通过在很长的寿命内每年繁殖一次来最大化繁殖成功。我们的结果强调了性别特异性特征如何驱动死亡率的差异并扩大物种的生态位空间。Further,觅食奖励和死亡风险之间的权衡可以不同地影响每个性别最大化健康的能力。
    Sex-specific phenotypic differences are widespread throughout the animal kingdom. Reproductive advantages provided by trait differences come at a cost. Here, we link sex-specific foraging strategies to trade-offs between foraging reward and mortality risk in sexually dimorphic northern elephant seals (Mirounga angustirostris). We analyse a decadal dataset on movement patterns, dive behaviour, foraging success and mortality rates. Females are deep-diving predators in open ocean habitats. Males are shallow-diving benthic predators in continental shelf habitats. Males gain six times more mass and acquire energy 4.1 times faster than females. High foraging success comes with a high mortality rate. Males are six times more likely to die than females. These foraging strategies and trade-offs are related to different energy demands and life-history strategies. Males use a foraging strategy with a high mortality risk to attain large body sizes necessary to compete for females, as only a fraction of the largest males ever mate. Females use a foraging strategy with a lower mortality risk, maximizing reproductive success by pupping annually over a long lifespan. Our results highlight how sex-specific traits can drive disparity in mortality rates and expand species\' niche space. Further, trade-offs between foraging rewards and mortality risk can differentially affect each sex\'s ability to maximize fitness.
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