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1.
  • 1 Subcoccinella 24-punctata (L.) is exclusively phytophagous, and is widely distributed throughout Britain.
  • 2 Under laboratory conditions the duration of pre-adult instars is about 6 weeks. Adults appear from the end of June onwards. Many enter reproductive diapause at the end of July, but remain active till the end of October.
  • 3 Reproductive diapause is determined by the interaction of photoperiod and temperature.
  • 4 Hibernation is unstable, and there may be high mortality in overwintering adults. These finally die during May and June.
  • 5 The cool temperate climate limits the population size, preventing it from reaching pest proportions.
  相似文献   

2.
Most ladybirds (Coleoptera: Coccinellidae) possess chemical protection against predators and signal its presence by less or more conspicuous coloration, which can be considered as a warning. Most ladybirds possess a dotted pattern, althougn the number, shape, and size of the spots, as well as their colour, varies considerably. Almost all ladybirds have a characteristic general appearance (body shape). We considered these traits to be used in ladybird recognition by avian predators. In the present study, we compared the reactions of avian predators ( Parus major ) caught in the wild, to four differently coloured ladybird beetles ( Coccinella septempunctata , Exochomus quadripustulatus , Subcoccinella vigintiquatuorpunctata , and Cynegetis impunctata ) and two artificial modifications of C. septempunctata ; the first was deprived of their elytral spotted pattern by painting it brown, the other had their elytra removed (i.e. altering their general ladybird appearance). Ladybirds with a spotted pattern were attacked less frequently than unspotted ones. Ladybirds with removed elytra were attacked much more often than any ladybird with a preserved general appearance. The results obtained in the present study suggest the high importance of the spotted pattern as well as general appearance in the ladybird recognition process. Additional experiments with naïve birds (hand-reared P. major ) demonstrated the innateness of the aversion to two differently spotted ladybird species ( C. septempunctata and Scymnus frontalis ).  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 98 , 234–242.  相似文献   

3.
生物多样性的编目和分类以及生物多样性监测是全球生物多样性研究的两个核心内容。物种编目是了解物种多样性的基础, 只有掌握物种分布格局及物种与环境的关系, 才能为物种监测和科学管理提供依据。作为浙江种子植物研究的“家底”, 本文在《浙江植物志(新编)》编研的基础上, 系统整理了浙江种子植物的物种名录。结果显示, 浙江共有种子植物212科1,469属4,430种, 其中野生植物有190科1,085属3,347种。所含种数多于100种的科有禾本科(285种)、莎草科(216种)、菊科(186种)、蔷薇科(153种)、兰科(126种)、蝶形花科(109种)和唇形科(108种); 含20种以上的属有15属, 包括薹草属(Carex, 126种)、刚竹属(Phyllostachys, 44种)、悬钩子属(Rubus, 44种)、冬青属(Ilex, 35种)、蓼属(Polygonum, 34种)、珍珠菜属(Lysimachia, 32种)、铁线莲属(Clematis, 31种)、景天属(Sedum, 28种)、槭属(Acer, 26种)、荚蒾属(Viburnum, 26种)、飘拂草属(Fimbristylis, 26种)、蒿属(Artemisia, 25种)、堇菜属(Viola, 22种)、葡萄属(Vitis, 21种)和山矾属(Symplocos, 21种)。其区系特点主要反映在: 物种丰富, 其科属组成多样; 保存了较多古老孑遗植物; 地理成分多样, 联系广泛, 由热带向温带过渡; 中国特有科2科、中国特有属45属、浙江(准)特有种近500种(含亚种和变种), 珍稀濒危植物丰富, 96种为国家重点保护植物; 外来植物多, 入侵风险大, 有些种已形成明显的危害。  相似文献   

4.
庐山蛾类区系研究   总被引:1,自引:0,他引:1  
方育卿 《动物学研究》1986,7(2):147-154
庐山,地处中亚热带北沿,北纬29.35°,东经115.59°,属亚热带东部季风区域。庐山襟江带湖,雨量充沛,植物种类繁多,种子植物有1800余种,隶属158科642属。因此,庐山蛾类也较丰富。笔者于1975年5月开始,对庐山蛾类进行了调查,共鉴定出蛾类455种。现将庐山蛾类区系报告如下。 区系分析 庐山蛾类已鉴定出32科340届455种。区系情况如表。 从表可以看出:  相似文献   

5.
Baum DA 《Systematic biology》1998,47(4):641-653
The individuality of species provides the basis for linking practical taxonomy with evolutionary and ecological theory. An individual is here defined as a collection of parts (lower-level entities) that are mutually connected. Different types of species individual exist, based on different types of connection between organisms. An interbreeding species is a group of organisms connected by the potential to share common descendants, whereas a genealogical species is integrated by the sharing of common ancestors. Such species definitions serve to set the limits of species at a moment of time and these slices connect through time to form time-extended lineages. This perspective on the nature of individuality has implications that conflict with traditional views of species and lineages: (1) Several types of connections among organisms may serve to individuate species in parallel (species pluralism); (2) each kind of species corresponds to a distinct kind of lineage; (3) although lineage branching is the most obvious criterion to break lineages into diachronic species, it cannot be justified simply by reference to species individuality; (4) species (like other individuals) have fuzzy boundaries; (5) if we wish to retain a species rank, we should focus on either the most- or least-inclusive individual in a nested series; (6) not all organisms will be in any species; and (7) named species taxa are best interpreted as hypotheses of real species. Although species individuality requires significant changes to systematic practice and challenges some preconceptions we may have about the ontology of species, it provides the only sound basis for asserting that species exist independently of human perception.  相似文献   

6.
We studied ground-dwelling spiders along a rural?Csuburban?Curban forest gradient representing increasing human disturbance using pitfall traps. We tested four known and two novel hypotheses: (1) increasing disturbance hypothesis (species richness is decreasing by disturbance); (2) matrix species hypothesis (the richness of open-habitat species is increasing by disturbance); (3) opportunistic species hypothesis (the richness of generalist species is increasing by disturbance); and (4) habitat specialist hypothesis (the number of the forest specialist species is decreasing by disturbance). As a consequence of urbanization, urban forests become drier and more open; thus, according to the new hypotheses, the number of (5) xerophilous species and (6) light-preferring species are increasing in the urban area. Our result did not support the increasing disturbance hypothesis, as the overall species richness increased from the rural sites to the urban ones. As predicted, the number of both the open-habitat and the generalist species increased towards the urban sites. The number of forest specialist species was higher in the suburban area than in the rural and urban area. Both xerophilous and light-preferring species were the most numerous in the urban area, supporting the xerophilous species and the light-preferring species hypotheses. Canonical correspondence analysis showed that the forest specialist species associated with the rural sites with higher amounts of decaying woods and more herbs or with the suburban sites with higher cover of leaf litter and higher relative humidity. Two generalist species and one open-habitat species were characteristic of urban sites with higher ground surface and air temperature.  相似文献   

7.
于2017年至2018年对广东丹霞山国家级自然保护区的翼手目动物进行调查,主要采用日栖息地与夜栖息地、捕食区网捕等调查方法,共调查到翼手目5科13属23种,其中蝙蝠科(Vespertilionidae)9属15种,菊头蝠科(Rhinolophidae)1属4种,蹄蝠科(Hipposideridae)1属2种,假吸血蝠科(Megadermatidae)1属1种,犬吻蝠科(Molossidae)1属1种。从区系组成来看,以东洋界为主(19种),其次为广布种(3种),古北界仅1种。从栖息类型上看,分为洞栖型、树栖型及建筑物栖息型,以洞栖型为主(15种),建筑物栖息型其次(12种),树栖型最少(5种),但其中9个物种的栖息地类型同时包含了上述3种栖息类型中的2种。本研究在广东丹霞山发现中国蝙蝠新分布记录1种,为卡氏伏翼(Hypsugo cadornae);而中印鼠耳蝠(Myotis indochinensis)为中国分布的再次确认。  相似文献   

8.
Guadalupe Island, an oceanic island in the northwest of Mexico, is an outlier of the California Floristic Province that has been disturbed by introduced goats for more than a century, with dramatic effects of goats on plant communities and local species extinctions. In 2004 the island went through a successful eradication program. Since then, six previously unrecorded species have been discovered and four supposed extinct species have been found again. Quantifying the true species richness of the island at the time of eradication, to set a benchmark for the future monitoring of this large-scale natural experiment, is both a challenge and a necessity. For this purpose, we estimated (a) current and (b) accumulated historical plant species richness of the island through accumulation functions. Estimation of current species richness was based on the geographical accumulation process of species richness (80 species) obtained from sampling 110 (50 m × 2 m) transects distributed along the island in year 2004. Historical species richness was estimated through the temporal accumulation of species richness (119 species) from botanical records (1,960 specimens reviewed) between 1875 and 2000. The predicted value of historical richness (213 species) is similar to known historical records (218 species), but estimation of current richness (203 species) is significantly higher than accepted extant plant richness (187 species). Our results suggest that currently there may be more plant species living in the island than estimated through recent botanical exploration. Future monitoring of the island as it recovers will clarify this hypothesis.  相似文献   

9.
10.
This paper evaluates both the ideas and empirical evidence pertaining to the control of species density in herbaceous plant communities. While most theoretical discussions of species density have emphasized the importance of habitat productivity and disturbance regimes, many other factors (e.g. species pools, plant litter accumulation, plant morphology) have been proposed to be important. A review of literature presenting observations on the density of species in small plots (in the vicinity of a few square meters or less), as well as experimental studies, suggests several generalizations: (1) Available data are consistent with an underlying unimodal relationship between species density and total community biomass. While variance in species density is often poorly explained by predictor variables, there is strong evidence that high levels of community biomass are antagonistic to high species density. (2) Community biomass is just one of several factors affecting variations in species density. Multivariate analyses typically explain more than twice as much variance in species density as can be explained by community biomass alone. (3) Disturbance has important and sometimes complex effects on species density. In general, the evidence is consistent with the intermediate disturbance hypothesis but exceptions exist and effects can be complex. (4) Gradients in the species pool can have important influences on patterns of species density. Evidence is mounting that a considerable amount of the observed variability in species density within a landscape or region may result from environmental effects on the species pool. (5) Several additional factors deserve greater consideration, including time lags, species composition, plant morphology, plant density and soil microbial effects.Based on the available evidence, a conceptual model of the primary factors controlling species density is presented here. This model suggests that species density is controlled by the effects of disturbance, total community biomass, colonization, the species pool and spatial heterogeneity. The structure of the model leads to two main expectations: (1) while community biomass is important, multivariate approaches will be required to understand patterns of variation in species density, and (2) species density will be more highly correlated with light penetration to the soil surface, than with above-ground biomass, and even less well correlated with plant growth rates (productivity) or habitat fertility. At present, data are insufficient to evaluate the relative importance of the processes controlling species density. Much more work is needed if we are to adequately predict the effects of environmental changes on plant communities and species diversity.  相似文献   

11.
清澜红树林保护区位于海南岛东北部文昌市境内,为全面了解其植物多样性,对其各类植被进行了调查。共记录到维管植物172种,隶属于62科148属。其中真红树植物24种,占全省真红树(26种)的92.31%,占全国(28种)的85.71%,占全世界(86种)的27.91%;在4040 m2样地内,共记录到高度1.5 m以上的红树植物29种3670株,其中重要值最高的为海桑Sonneratis caseolaris,其次是海莲Bruguiera sexangula,两者重要值依次是12.90和12.33;但在个体数量上,角果木Ceriops tagal和红海榄Rhizophora stylosa占优势。清澜港红树林保护区自然植被具体划分为1个植被类型组、1个植被类型、2个群系组和12个群系。经过19年的演变,木榄Bruguiera gymnorrhiza和水椰Nypa fruticans群落消失,瓶花木Scyphiphora hydrophyllacea群落也破碎成零星分布,新出现了木果楝Xylocarpus granatum群落,其他如海桑Sonneratia caseolaris等群落则继续保持稳定,变化很小。  相似文献   

12.
新疆石竹科的繁缕亚科、裸果木亚科共有植物14属63种3变种。占新疆石竹总属数66.7%总种数48.2%。从垂直分布来看,主要分布于阿尔泰山和天山的亚高山草甸带和森林草甸带,昆仑山的高寒荒漠草原也有一定的分布。从水平分布看,主要有五个分布较集中的区域,即:阿尔泰泰山地,准噶尔西部山地,天山中西部山地、天山东部山地、昆仑山和帕米尔高原。在区系组成中,北温带成分21种,占31.9%;温带亚洲成分14种,  相似文献   

13.
杜维波  卢元 《生物多样性》2019,27(11):1260-773
物种编目是了解生物多样性的基础。本文收集已出版的专著和文献, 查阅标本馆的馆藏标本信息, 在此基础上, 对黄土高原的石松类和蕨类植物的多样性和地理分布数据进行统计和分析。科属排列采用Flora of China的分类系统, 科属界定依据分子系统学的最新研究成果。结果表明, 黄土高原共有石松类和蕨类植物18科42属165种2亚种5变种, 其中中国特有种35种, 占总种数的20.35%。种类数量最多的5个科依次为凤尾蕨科(29种, 含种下单位, 下同)、鳞毛蕨科(28种)、水龙骨科(19种)、蹄盖蕨科(16种)和铁角蕨科(16种); 种类数量最多的6个属依次为铁角蕨属(Asplenium, 16种)、鳞毛蕨属(Dryopteris, 15种)、耳蕨属(Polystichum, 12种)、岩蕨属(Woodsia, 11种)、卷柏属(Selaginella, 10种)和瓦韦属(Lepisorus, 10种)。黄土高原的石松类和蕨类植物中, 无珍稀濒危保护植物, 无中国特有属。依据生态类型可划分为4类, 即土生植物(112种)、石生植物(75种)、附生植物(18种)、水生植物(3种), 该区域石松类和蕨类植物土生或石生的种类占总种数的89.53%。在地理分布上, 黄土高原石松类和蕨类处于我国现生类群分布的边缘区域, 这与我国的石松类和蕨类分布规律基本一致。  相似文献   

14.
Summary Four concepts are considered for the trophic level of a species in a community food web. The long-way-up-level (or LU-level) of species A is the length of the longest simple food chain from a basal species (one with no prey in the web) to A. (A simple chain is a chain that does not pass through any given species more than once.) The short-way-up-level (SU-level) of species A is the length of the shortest chain from a basal species to A. The long-way-down-level (LD-level) of species A is the length of the longest simple chain from species A to a top species (one with no consumers in the web). The short-way-down-level (SD-level) of species A is the length of the shortest chain from species A to a top species. The stratigraphy of a web is the analogue for species of the pyramid of numbers for individuals: it is the frequency distribution of species according to level. The LU-, SU-, LD-, and SD-stratigraphies of the seven webs in the Briand-Cohen collection with 30 or more trophic species reveal no species with LU-level or LD-level more than 6, no species with SU-level more than 3, and no species with SD-level more than 2. In all seven webs, SD-levels are stochastically less than SU-levels: species tend to be closer to a top predator than to a basal species. Two stochastic models of food web structure (the cascade model and the homogeneous superlinear model) correctly predict that 95% or more of species should have LU-level and LD-level in the range 0–6. The models also correctly predict some details of the distribution of species in the SU- and SD-stratigraphies, particularly the fraction of species in level 1. The models do not, in general, correctly predict the distribution of species within the range 0–6 of LU-levels and LD-levels.  相似文献   

15.
黄土高原豆科植物区系的研究   总被引:4,自引:0,他引:4  
本区豆科植物共49属,217种,分别为中国豆科植物总数的22.5%和14.6%。在区系组成中,古地中海成分48种,占22.1%;东亚成分42种,占19.4%;中国喜玛拉雅成分21种,占9.7%;欧亚温带—黄土高原—青藏高原成分23种,占10.6%;特有成分22种,占10.1%;广布成分38种,占17.5%;归化成分23种,占10%。因此,本区是以古地中海成分和东亚成分为主。在自然景观中,旱生的草木和灌木起着重要作用,占有自然植被中的重要优势,是森林草原和草原的重要组成。  相似文献   

16.
苏州地区外来入侵植物组成及分布   总被引:2,自引:0,他引:2  
为了解苏州外来入侵植物的种类组成及分布概况,对苏州地区6个县市(包括常熟、昆山、苏州、太仓、吴江和张家港)26个样点内不同生境中的外来入侵植物进行了调查分析.调查结果显示:每个样点有外来人侵植物7~25种,平均每个样点有17.9种.在26个样点中观察到外来入侵植物57种,隶属于19科45属;其中菊科(Compositae)种类最多(23种),占总种数的40.4%;豆科(Leguminosae)、玄参科(Scrophulariaceae)、禾本科(Poaceae)、伞形科(Apiaceae)、苋科(Amaranthaceae)和旋花科(Convolvulaceae)种类也较多.原产于北美洲和欧洲的种类分别有20和12种,分别占总种数的35.1%和21.0%;还有17种原产于美洲的其他区域,少数种类原产于非洲、西亚和地中海地区.在57种外来入侵植物中,草本植物有55种,非多年生植物有44种,分别占总种数的96.5%和77.2%.有18种的频度超过50%,其中加拿大一枝黄花(Solidago canadensis L.)和一年蓬[Erigeron annuus (L.) Pers.]的频度最高,分别达到96.15%和92.31%,且多度等级均属于极多级(Soc);空心莲子草[ Ahernanthera philoxeroides( Mart.) Griseb.]和白车轴草(Trifolium repens L.)的频度也均在80%以上,且多度等级也属于极多级(Soc).调查结果表明:苏州地区外来植物入侵现象比较严重.  相似文献   

17.
Contribution of rarity and commonness to patterns of species richness   总被引:5,自引:0,他引:5  
There is little understanding in ecology as to how biodiversity patterns emerge from the distribution patterns of individual species. Here we consider the question of the contributions of rare (restricted range) and common (widespread) species to richness patterns. Considering a species richness pattern, is most of the spatial structure, in terms of where the peaks and troughs of diversity lie, caused by the common species or the rare species (or neither)? Using southern African and British bird richness patterns, we show here that commoner species are most responsible for richness patterns. While rare and common species show markedly different species richness patterns, most spatial patterning in richness is caused by relatively few, more common, species. The level of redundancy we found suggests that a broad understanding of what determines the majority of spatial variation in biodiversity may be had by considering only a minority of species.  相似文献   

18.
基于七姊妹山自然保护区内6 hm~2监测样地多度数据,通过累计经验分布曲线(ECDF)表征该样地内不同生活型功能群的物种-多度分布格局,并采用6种模型对各功能群不同取样尺度物种等级-多度曲线进行拟合并检验其拟合效果,分析多度格局与模型拟合在不同尺度间的差异,探讨其背后的生态学过程与机制。结果表明:(1)各尺度下落叶种比常绿种的物种数多,物种多样性指数更大,但个体数相对较少;不同功能群稀有种比例排序为:落叶种所有种常绿种。(2)6种模型中的断棍模型的拟合效果较差;中大尺度(50 m×50 m、100 m×100 m)上不同生活型树种多度分布能接受的模型较少,除大尺度的常绿树种外,拟合最优模型均为对数正态分布模型,大尺度的常绿树种拟合最优模型为中性模型;小尺度上(20 m×20 m)常绿树种的最优模型为对数正态分布模型,落叶树种最优模型为生态位优先模型,所有树种在小尺度最优模型为Zipf-Mandelbrot模型。研究认为,随着尺度逐渐扩大,中性过程较生态位过程对物种-多度格局的解释力度更大,落叶树种物种多度格局的形成机制较常绿树种更接近于样地所有树种物种-多度格局的形成机制。  相似文献   

19.
Abstract Processes acting on different spatial and temporal scales may influence local species richness. Ant communities are usually described as interactive and therefore determined by local processes. In this paper we tested two hypotheses linked to the question of why there is local variation in arboreal ant species richness in the Brazilian savanna (‘cerrado’). The hypotheses are: (i) there is a positive relationship between ant species richness and tree species richness, used as a surrogate of heterogeneity; and (ii) there is a positive relationship between ant species richness and tree density, used as a surrogate of resource availability. Arboreal ants were sampled in two cerrado sites in Brazil using baited pitfall traps and manual sampling, in quadrats of 20 m × 50 m. Ant species richness in each quadrat was used as the response variable in regression tests, using tree species richness and tree density as explanatory variables. Ant species richness responded positively to tree species richness and density. Sampling site also influenced ant species richness, and the relationship between tree density and tree species richness was also positive and significant. Tree species richness may have influenced ant species richness through three processes: (i) increasing the variety of resources and allowing the existence of a higher number of specialist species; (ii) increasing the amount of resources to generalist species; and (iii) some other unmeasured factor may have influenced both ant and tree species richness. Tree density may also have influenced ant species richness through three processes: (i) increasing the amount of resources and allowing a higher ant species richness; (ii) changing habitat conditions and dominance hierarchies in ant communities; and (iii) increasing the area and causing a species–area pattern. Processes acting on larger scales, such as disturbance, altitude and evolutionary histories, as well as sampling effect may have caused the difference between sites.  相似文献   

20.
崔宝凯  余长军 《生态学报》2011,31(13):3700-3709
本文在过去10 a野外调查和室内鉴定及分析研究的基础上,对大兴安岭林区多孔菌的区系组成和种群结构进行了分析,发现大兴安岭林区的多孔菌具有较高的多样性,共有5目11科56属129种,占中国多孔菌区系的21.36%,优势科是多孔菌科。种的区系地理成分分为7类,以北温带成分和世界广布成分为主,具有明显的北温带成分的区系特征。大兴安岭的多孔菌常见种较多,种群结构中共生菌3种,寄生菌27种,腐生菌占大多数,有99种。在能够引起木材腐朽的126种真菌中,白腐菌93种,占多数,褐腐菌33种,占少数,但该地区褐腐菌所占比例明显高于全国范围内褐腐菌在多孔菌中的比例。通过对大兴安岭主要树种上的种群结构进行比较,表明阔叶树上的木材腐朽菌绝大部分是白色腐朽菌,而针叶树上的白腐菌与褐腐菌数量相差不大,褐腐菌对于针叶林特别是落叶松的更新具有非常重要的作用。  相似文献   

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