Selection analysis on the rapid evolution of a secondary sexual trait

Evolutionary analyses of population translocations (experimental or accidental) have been important in demonstrating speed of evolution because they subject organisms to abrupt environmental changes that create an episode of selection. However, the strength of selection in such studies is rarely measured, limiting our understanding of the evolutionary process. This contrasts with long-term, mark–recapture studies of unmanipulated populations that measure selection directly, yet rarely reveal evolutionary change. Here, we present a study of experimental evolution of male colour in Trinidadian guppies where we tracked both evolutionary change and individual-based measures of selection. Guppies were translocated from a predator-rich to a low-predation environment within the same stream system. We used a combination of common garden experiments and monthly sampling of individuals to measure the phenotypic and genetic divergence of male coloration between ancestral and derived fish. Results show rapid evolutionary increases in orange coloration in both populations (1 year or three generations), replicating the results of previous studies. Unlike previous studies, we linked this evolution to an individual-based analysis of selection. By quantifying individual reproductive success and survival, we show, for the first time, that males with more orange and black pigment have higher reproductive success, but males with more black pigment also have higher risk of mortality. The net effect of selection is thus an advantage of orange but not black coloration, as reflected in the evolutionary response. This highlights the importance of considering all components of fitness when understanding the evolution of sexually selected traits in the wild.     

南昌市不同植物类群叶片氮磷浓度及其化学计量比

对南昌大学前湖校区89种主要植物叶片的N、P浓度及其化学计量比进行了研究,结果表明:乔灌、常绿、针叶、种子、裸子和单子叶植物类群的N浓度分别低于相对应的草本、落叶、阔叶、蕨类、被子和双子叶植物类群,而C3和C4植物差异不显著;乔灌、常绿和裸子植物类群的P浓度含量分别低于相对应的草本、落叶和被子植物类群,而针叶和阔叶、蕨类和种子、单子叶和双子叶、C3和C4植物类群间差异不显著;乔木、阔叶、被子和双子叶植物类群叶片N/P分别高于相对应的灌草、针叶、裸子和单子叶植物类群,而常绿和落叶、蕨类和种子、C3和C4植物类群之间差异不显著.可见,不同类型植物对N和P的吸收利用存在差异,且对不同养分供应采取不同的适应对策.结合研究区土壤养分现状,建议优先选择常绿、针叶、裸子和单子叶植物类群作为城市园林植物.     

Biological activity of Hyposidra talaca nucleopolyhedrovirus against all instar stages of a destructive tea pest Hyposidra talaca (Lepidoptera: Geometridae) in India

Hyposidra talaca (Walker) (Lepidoptera: Geometridae) is the most harmful pest of northeastern tea hub of India that devastates the tea production by feasting on the tea leaves. Hyposidra talaca nucleopolyhedrovirus (HytaNPV) is a natural enemy of the aforesaid pest, as it poses great obstruction in the multiplication of the pest by causing significant larval mortality. The study was undertaken to screen the virus activity against first to fifth instar H. talaca larvae. Early instar stages are found more susceptible than the late stages as they tend to reflect highest LC₅₀ value for fifth instar as 4.3 × 10⁷ POB/ml and lowest LC₅₀ value for first instar as 7 × 10⁴ POB/ml within seven days of inoculation. LT₅₀ values vary between 2.47 and 8.45 days for neonates to fifth instar. The high record of virulence of HytaNPV indicates its bright prospect as a useful microbial biopesticide.     

Preadapted for invasiveness: do species traits or their plastic response to shading differ between invasive and non‐invasive plant species in their native range?

Aim Species capable of vigorous growth under a wide range of environmental conditions should have a higher chance of becoming invasive after introduction into new regions. High performance across environments can be achieved either by constitutively expressed traits that allow for high resource uptake under different environmental conditions or by adaptive plasticity of traits. Here we test whether invasive and non‐invasive species differ in presumably adaptive plasticity. Location Europe (for native species); the rest of the world and North America in particular (for alien species). Methods We selected 14 congeneric pairs of European herbaceous species that have all been introduced elsewhere. One species of each pair is highly invasive elsewhere in the world, particularly so in North America, whereas the other species has not become invasive or has spread only to a limited degree. We grew native plant material of the 28 species under shaded and non‐shaded conditions in a common garden experiment, and measured biomass production and morphological traits that are frequently related to shade tolerance and avoidance. Results Invasive species had higher shoot–root ratios, tended to have longer leaf‐blades, and produced more biomass than congeneric non‐invasive species both under shaded and non‐shaded conditions. Plants responded to shading by increasing shoot–root ratios and specific leaf area. Surprisingly, these shade‐induced responses, which are widely considered to be adaptive, did not differ between invasive and non‐invasive species. Main conclusions We conclude that high biomass production across different light environments pre‐adapts species to become invasive, and that this is not mediated by plasticities of the morphological traits that we measured.     

论植物园的活植物收集

对植物园活植物收集评价、引种中的取样方法和迁地保护种群大小等问题进行了论述.对活植物收集的评价包括科学性和代表性,最具有科学意义的是经过调查从野外收集的有完整记录的材料,其次是从植物园等机构 引种的有记录的材料,再次是从各地引种的基本上无记录的材料.根据收集物的代表性可分为具有保护意义的收集和保护性收集.取样技术主要针对保护性收集而言,要求收集样本能涵盖该物种95%以上、频率大于5%的等位基因.活植物收集种群的大小应从科学性和现实性二方面来考虑,对植物园里大量的具有保护意义的收集,其种群大小为乔木10～20株,灌木40～50株,草本100～200株;对于保护性收集则至少为乔木50～100株,灌木200株或更多,草本300～500株以上.另外,对当前植物园活植物收集圃建设的一些重要问题也进行了探讨.     

几种花卉植物对污泥中铅的富集特征

土地利用是资源化利用城市污水厂污泥的有效途径。为了解污泥中重金属污染物在土壤、植物之间的迁移富集规律,选用8种园林用植物进行污泥混配土种植实验。结果表明,植物对污泥混配土土壤中铅的富集能力,以及铅在植物中各器官的富集系数均不同,且不同种类植物差别较大。植物根部对铅有较强的富集能力,其次是叶和茎。菊花对铅的富集能力较强。植物对土壤中铅的富集能力也受土壤铅含量和赋存形态影响。     

两个菜用枸杞品种的生长特性及品质分析

对两个菜用枸杞品种的主要生长特性、营养成分及食用性研究表明,大叶品种嫩芽平均产量显著高于小叶品种;大叶品种较耐高温,小叶品种较耐低温;生产上可进行大、小叶品种搭配种植,能有效提早和延长采收期,从而提高单位面积产量和经济效益。此外,小叶品种嫩芽的蛋白质、VitC含量高于大叶品种。两个品种风味各具特色,其适宜的消费群体亦有所差异。     

Short distances between extreme microhabitats do not result in ecotypes in Syntrichia caninervis

Abstract

Phenotypic variation occurs in many populations of plants. When this variation occurs along an environmental gradient, the immediate question is whether the variation is attributed to phenotypic plasticity, ecotypes, or some combination of the two. The moss Syntrichia caninervis appears morphologically variable along an environmental gradient changing rapidly from low light, low temperature, and high moisture levels in the understory microhabitat to high light, high temperature, and low moisture levels in the intershrub microhabitat. We tested for the presence of physiological variation using recovery from a heat-shock event in a mimicked microhabitat light environment, and for morphological variation using a common garden with the ultimate goal of attributing observed variation to plasticity, genetic variation, or a combination. The results suggest that plasticity plays a large role in trait variation. Photosynthetic recovery depended on the current light levels of an environment and not the original microhabitat. The supposed morphological variation in the field was not reflected in the test traits (awn length, leaf area, and shoot volume) and further growth in a common garden continued to show no variation between microhabitats.     

Young,intact and nested retrotransposons are abundant in the onion and asparagus genomes

Background and Aims

Although monocotyledonous plants comprise one of the two major groups of angiosperms and include >65 000 species, comprehensive genome analysis has been focused mainly on the Poaceae (grass) family. Due to this bias, most of the conclusions that have been drawn for monocot genome evolution are based on grasses. It is not known whether these conclusions apply to many other monocots.

Methods

To extend our understanding of genome evolution in the monocots, Asparagales genomic sequence data were acquired and the structural properties of asparagus and onion genomes were analysed. Specifically, several available onion and asparagus bacterial artificial chromosomes (BACs) with contig sizes >35 kb were annotated and analysed, with a particular focus on the characterization of long terminal repeat (LTR) retrotransposons.

Key Results

The results reveal that LTR retrotransposons are the major components of the onion and garden asparagus genomes. These elements are mostly intact (i.e. with two LTRs), have mainly inserted within the past 6 million years and are piled up into nested structures. Analysis of shotgun genomic sequence data and the observation of two copies for some transposable elements (TEs) in annotated BACs indicates that some families have become particularly abundant, as high as 4–5 % (asparagus) or 3–4 % (onion) of the genome for the most abundant families, as also seen in large grass genomes such as wheat and maize.

Conclusions

Although previous annotations of contiguous genomic sequences have suggested that LTR retrotransposons were highly fragmented in these two Asparagales genomes, the results presented here show that this was largely due to the methodology used. In contrast, this current work indicates an ensemble of genomic features similar to those observed in the Poaceae.