534 resultados para Phenacoccus Parvus


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Heteronomous hyperparasitoids are parasitic wasps with sex-related host relationships that are unique to a group of genera in the chalcidoid family Aphelinidae. Females are primary parasitoids of various sedentary bugs (mainly, scale insects, mealy bugs, and whiteflies). Males, in contrast, are hyperparasitic, and they frequently develop at the expense of female conspecifics. Alloparasitoids constitute a special category of heteronomous hyperparasitoids, for their males never develop through female conspecifics. The existence of alloparasitic host relationships and the utility of the category 'alloparasitoid' have both been questioned. Here, we present results that confirm the existence of the alloparasitic way of life among heteronomous aphelinids. We investigated an undescribed species of Coccophagus (Hymenoptera: Aphelinidae), an Australian parasitoid that attacks the introduced lantana mealy bug, Phenacoccus parvus Morrison (Homoptera: Pseudococcidae), in Queensland. A year-long field survey regularly returned large numbers of female Coccophagus spec. near gurneyi individuals from P. parvus (total n = 4212), but only few males (n = 11). Males emerged from samples only when the encyrtid parasitoid Anagyrus diversicornis (Howard) (Hymenoptera: Encyrtidae) was present in samples in relatively high numbers. Laboratory oviposition tests confirmed that A. diversicornis is a male host and showed that males do not develop at the expense of conspecific females. Other studies show that males are attracted in numbers to virgin females held in cages above mealy bug-infested Lantana montevidensis (Spreng.) Briq. (Verbenaceae) in the field, demonstrating that they are common in the population as a whole. This confirms that the males need hosts other than conspecific females and that their usual hosts are present outside of the lantana/P. parvus system. The implications of these results for developing a realistic classification of heteronomous host relationships are discussed.

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The spatial distribution of stage-specific abundance and reproduction of the copepod Paracalanus parvus were studied from October 2005 to September 2006 in the Jiaozhou Bay. This copepod occurred continuously in this bay throughout the year. The species reached the lowest abundance in April and peaked in June. From October to December, distribution center mainly occurred in offshore water and at the mouth of the bay. In winter, early copepodites and adults gradually decreased and till February, most of the population was only comprised of CIV-CV stages. Overwintering copepodites matured in March and males tended to mature before female. From May to September, each stage occurred in the population and gradually reached high abundance. Temperature and chlorophyll a (Chl-a) concentration in the three stations can't clearly explain the seasonal variation in stage-specific abundance, so we surmised the important effect of the Yellow Sea. Egg production rate (EPR) reached its lowest in winter and peaked in June at 60.8 eggs female(-1) day(-1) in nearshore water. In the warming period, EPR in nearshore water was statistically higher and EPR > 10 eggs female(-1) day(-1) lasted longer than that in offshore water, showing the importance of nearshore water for recruitment of R parvus. Our study showed that EPR was positively related to temperature and total chlorophyll a in offshore water and mouth of the bay. In nearshore water, the relationships between EPR and temperature and Chl-a in three size fractions were not the same as those in offshore water, suggesting complicated ecosystem in such a eutrophic area in warming period. (C) 2008 Elsevier Ltd. All rights reserved.

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The life cycle of infusorians belonging to genus Colpoda, dormant cysts of which were found on planktic crustaceans of the Black Sea coastal waters, is described. Population strength of Colpoda is maximum in autumn. The infusorians had no harmful effect on their host. It has been noted that Colpoda enhances decomposition of dead animals.

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Introduction Many marine planktonic crustaceans such as copepods have been considered as widespread organisms. However, the growing evidence for cryptic and pseudo-cryptic speciation has emphasized the need of re-evaluating the status of copepod species complexes in molecular and morphological studies to get a clearer picture about pelagic marine species as evolutionary units and their distributions. This study analyses the molecular diversity of the ecologically important Paracalanus parvus species complex. Its seven currently recognized species are abundant and also often dominant in marine coastal regions worldwide from temperate to tropical oceans. Results COI and Cytochrome b sequences of 160 specimens of the Paracalanus parvus complex from all oceans were obtained. Furthermore, 42 COI sequences from GenBank were added for the genetic analyses. Thirteen distinct molecular operational taxonomic units (MOTU) and two single sequences were revealed with cladistic analyses (Maximum Likelihood, Bayesian Inference), of which seven were identical with results from species delimitation methods (barcode gaps, ABDG, GMYC, Rosenberg's P(AB)). In total, 10 to 12 putative species were detected and could be placed in three categories: (1) temperate geographically isolated, (2) warm-temperate to tropical wider spread and (3) circumglobal warm-water species. Conclusions The present study provides evidence of cryptic or pseudocryptic speciation in the Paracalanus parvus complex. One major insight is that the species Paracalanus parvus s.s. is not panmictic, but may be restricted in its distribution to the northeastern Atlantic.

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1. th. Lyrische gedichte. Lesearten der ausgabe vom jahre 1772. Anmerkungen.--2. th. Vermischte gedichte. Zwanzig oden aus dem Horaz. Lesearten der ausgabe vom jahre 1772. Anmerkungen. Ramlers leben.

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This thesis examines assemblages of wood-decaying fungi in Finnish old-growth forests, and patterns of species interactions between fruit bodies of wood-rotting Basidiomycetes and associated Coleoptera. The present work is a summary of four original publications and a manuscript, which are based on empirical observations and deal with the prevalence of polypores in old-growth forests, and fungicolous Coleoptera. The study area consists of eleven old-growth, mostly spruce- and pine-dominated, protected forests rich in dead wood in northern and southeastern Finland. Supplementary data on fungus beetle interactions were collected in southern Finland and the Åland Islands. 11251 observations of fruit bodies from 153 polypore species were made in 789 forest compartments. Almost a half of the polypore species demonstrated a distinct northern or southeastern trend of prevalence. Polypores with a northern prevalence profile were in extreme cases totally absent from the Southeast, although almost uniformly present in the North. These were Onnia leporina, Climacocystis borealis, Antrodiella pallasii, Skeletocutis chrysella, Oligoporus parvus, Skeletocutis lilacina, and Junghuhnia collabens. Species with higher prevalence in the southeastern sites were Bjerkandera adusta, Inonotus radiatus, Trichaptum pargamenum, Antrodia macra, and Phellinus punctatus. 198 (86%) species of Finnish polypores were examined for associated Coleoptera. Adult beetles were collected from polypore basidiocarps in the wild, while their larvae were reared to adulthood in the lab. Spatial and temporal parallels between the properties of polypore fruit body and the species composition of Coleoptera in fungus beetle interactions were discussed. New data on the biology of individual species of fungivorous Coleoptera were collected. 116 species (50% of Finnish polypore mycota) were found to host adults and/or larvae of 179 species from 20 Coleoptera families. Many new fungus beetle interactions were found among the 614 species pairs; these included 491 polypore fruit body adult Coleoptera species co-occurrences, and 122 fruit body larva interrelations. 82 (41%) polypore species were neither visited nor colonized by Coleoptera. The total number of polyporicolous beetles in Finland is expected to reach 300 species.

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During a re-examination of museum specimens of Triplophysa species, some specimens that had been collected from the Jialonghe River in Yunnan Province, China, in April 1975, were identified as a new species. Triplophysa parvus n. sp. can be distinguished

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The genus Sarcocheilichthys is a group of small cyprinid fishes comprising 10 species/sub-species widely distributed in East Asia, which represents a valuable model for understanding the speciation of freshwater fishes in East Asia. In the present study, the molecular phylogenetic relationship of the genus Sarcocheilichthys was investigated using a 1140 bp section of the mitochondrial cytochrome b gene. Two different tree-building methods, maximum parsimony (MP) and Bayesian methods, yielded trees with almost the same topology, yielding high bootstrap values or posterior probabilities. The results showed that the genus Sarcocheilichthys consists of two large clades, clades I and II. Clade I contains Sarcocheilichthys lacustris, Sarcocheilichthys sinensis and Sarcocheilichthys parvus, with S. parvus at a basal position. In clade II, Sarcocheilichthys variegatus microoculus is at a basal position; samples of the widespread species, Sarcocheilichthys nigripinnis, form a large subclade containing another valid species Sarcocheilichthys czerskii. Sarcocheilichthys kiangsiensis is retained at an intermediate position. Since S. czerskii is a valid species in the S. nigripinnis clade, remaining samples of S. nigripinnis form a paraphyly. This speciation process is attributed to geographical isolation and special environmental conditions experienced by S. czerskii and stable environments experienced by the other S. nigripinnis populations. This type of speciation process was suggested to be very common. Samples of Sarcocheilichthys sinensis sinensis and Sarcocheilichthys sinensis fukiensis that did not form their own monophyletic groups suggest an early stage of speciation and support their sub-species status. Molecular clock analysis indicates that the two major lineages of the genus Sarcocheilichthys, clades I and II diverged c. 8.89 million years ago (mya). Sarcocheilichthys v. microoculus from Japan probably diverged 4.78 mya from the Chinese group. The northern-southern clades of S. nigripinnis began to diverge c. 2.12 mya, while one lineage of S. nigripinnis evolved into a new species, S. czerski, c. 0.34 mya. (C) 2008 The Authors Journal compilation (C) 2008 The Fisheries Society of the British Isles.

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The genus Yunnanilus Nichols, 1925 is revised; Eonemachilus Berg, 1938 is a junior subjective synonym. Yunnanilus includes at least nine described species and five undescribed species. The status of Y; salmonides Chaudhuri is still incertae sedis. Six new species are described: Y. parvus, Y: altus, Y; pachycephalus, X niger, Y. macrogaster and Y. paludosus. The last three species occur sympatrically in a small endorheic basin of eastern Yunnan; they developed different feeding specializations which allowed them to use different niches. Other species also have peculiar specializations. The diversity of feeding habits and related adaptations in Yunnanilus is greater than in the whole subfamily Nemacheilinae and is one more example of supralimital specialization. Speciation of fishes on the Yunnan Plateau is discussed. Several species are endangered or possibly extinct. Introduction

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裂腹鱼类起源鳃亚科鱼类的观点得到了多数学者的支持。但是,鱼巴亚科鱼类是一个非常庞杂的类群,裂腹鱼类究竟起源于鳃亚科的哪一个小类群或裂腹鱼类与哪个小类群更为接近?这样的小类群又怎样随着急剧隆起的青藏高原峥演化发展成为现今的裂腹鱼类?不同的学者从不同的研究领域出发,得出了较为不一致甚至是相互对立的结论。裂腹鱼类(我国有11属,76种和亚种)均为小型鳞片的鱼类,与鳃亚科中一些具有小型鳞片的属种较为相似,即,妒鲤属(凡rCO~)的3个亚种、似鳃属(Lztciocyprinus)的2个种,金线纪属(Sinocyclocheilus)的26种或亚种,本文将这些具细小鳞片的鳃亚科鱼类统称为细鳞鳃鱼类(small-scaledbarbids)。为了探讨细鳞鱼巴类和裂腹鱼类的系统发育关界本文应用分支系统学的方法和原理,选择小裂腹鱼S.(R)parvus、中甸叶须鱼P.c.chunglienensis、松藩裸鲤。Gp.potanini、单纹似鳡L.langsoni、花妒鲤P.pingiregani、抚仙金线鱼巴s.师分别作为裂腹鱼类和细鳞鱼巴类中各分类:阶元的代,作为内a为了确考险状的进化极向并进一步探讨细鳞鱼巴各分类阶元与其他纪亚科和鲤亚科鱼类的系统关系,又选择了鳃亚科中的保山四须纪B.baoshanensis、云南四作为内群,并以螂鱼C.auratus、祀麓鲤C.(C)chilia作为外类群,用来对裂腹鱼类和细鳞鳃类进行性状的极化和系统发育分析。通过对12种24尾标本的外部形态和骨骼特征的全面观察,选择了63个性状进行描述和比较,并构建了供系统发育分析的特征矩阵。应用PAUP程序对特征矩阵进行运算,得出了包括外类群在内最简约的系统发育分支图。主要研究结论如下:(l)鲤亚科与包括裂腹鱼类在内的鳃亚科鱼类之间在很多特征方面存在着比较明显的差异,除了臀鳍最末一根不分枝鳍条坚硬、具锯齿;背鳍分枝多于1。根;第一椎体横突退化等特征外,还有镖的前后比例、前鳄骨的特征、尾舌骨的形状,基枕骨的骨质盘特征等诸多特征存在着显著差异。支持了陈湘舞等(1984)将鲤亚科和纪亚科分别作为独立亚科的观点。卿通过选取不同的外类群,在各种不同的条件下对特征数据矩阵进行运算和分析,除极少数(1个)结果外(当以祀麓鲤为唯一外群时,由34来看,它们都是第三纪末期以来由原始的鳃亚科鱼类演化而来的,适应过共同的寒冷环境(青藏高原的急剧隆升导致的寒冷气候和河川急流和青藏高原的大幅度隆起,引起了地貌环境的急剧改变,云贵高原一带也发生了差异性的升降运动。同时,全球性气温下降,常年性冰盖由北向南大幅度推进的寒冷气候环境)(曹文宣等,1981;王大忠等,2000)。裂腹鱼类和似鳃、妒鲤的起源时间可能稍晚一些。可以设想,第三纪末期的鳃亚科鱼类物种分化不是很多,相互之间的亲缘关系较近,分布于'青藏高原的原始鳃亚科鱼类和分布于云贵高原的原始鳃亚科鱼类分布经历了各自独特的地质、气候等环境条件,演化成为当今的裂腹鱼类和金线纪鱼类。至于似媳和妒鲤,除了经历与鳃亚科鱼类和金线鳃鱼类共同的寒冷水环境外,它们还向着肉食性的方向进行演化。(3)裂腹鱼类的3个代表种都聚在一起,其内部关系和与其他种的关系都较为稳定,为鳃亚科鱼类中较为特化的一支。与陈湘舞等(1984)、曹文宣等(1981)的观点较为一致,即,裂腹鱼类起源于纪亚科鱼类。晗(4)似媳和妒鲤之间的亲缘关系最近,它们很可能起源于最近的共同祖先。尽管二者作为一个单系的支持率并不是很高(大于50%,小于60%),但它们在个别特征(咽喉齿的排列方式、咽骨的形态特征)上表现其他鲤科鱼类所不具有的独特特征(附图1的。(5:)裂腹鱼类与妒鲤+似鳃的系统关系最近,这意味着裂腹鱼类和妒鲤+似鳃有最近的共同祖先或它们之间的关系较它们与金线鳃鱼类的关系更a(e)应用特征分析和系统发育分析所得的结论,综合对鳃系鱼类染色体特征的分析,认为裂腹鱼类和细鳞鳃鱼类在染色体分组组成、哪值等方面的相似特征,极有可能是在进化过程中经历了类似的寒冷水环境。它们之间的核型特征相似,只是说明了它们之间较近的系统发育关系,不支持妒鲤和金线靶是鳃亚科和裂腹鱼亚科之间的中间演化类型的观点。染色体的进化和外部形态特征的进化在纪系鱼类中存在着不平行的现象。(7)通过国内外鱼类学者对鲤科鱼类和纪亚科鱼类各分类单元定义的比较,结合本文的研究结果,认为国外学者的一些分类系统仍然存在一些尚待解决的问题,故建议目前暂不宜将之引入到我国的鱼类分类系统中。

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本文研究了胶州湾内1988年5月至1989年5月,小拟哲水蚤[Paracalanus parvus(Claus)]、双刺纺锤水蚤[Acartia bifilosa (Giesbrecht)]、太平洋纺锤水蚤(A. pacifica steuer)和1982年5月至1983年4月中华哲水蚤(Calanus sinicus Brodsky)的种群结构和种群数量的季节变化。双剌纺锤水蚤和太平纺锤水蚤在胶州湾是季节性出现的种类,它们能产生休眠卵,本文对其休眠卵数量的季节变化以及影响休眠卵产生和孵化的因素进行了初步的探讨。本文还研究了体长的季节变化以及温度和食物条件对体长的影响。

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浮游动物是河口生态系统的重要组成部分,在食物网中,浮游动物是浮游植物捕食者,对浮游植物有摄食压力,所以控制浮游植物数量的增长。同时,浮游动物还是鱼类的饵料,从而影响渔业资源的数量。长江口是各种经济鱼、虾和蟹的重要产卵场、索饵场和洄游场。长江口各个分汊的分流量的差异较大,导致不同分汊的水文环境明显不同,其中最为明显就是北港和北支水域。然而以往对浮游动物的研究仅限于某一水域,没有对整体水域进行研究,本文选择最具代表性的北港和北支水域,对两水域浮游动物的群落生态特征进行比较研究。 本论文的数据来源于2004年5、8、11月和2005年2月在长江口北港和北支水域4个航次的海洋综合调查资料。通过采用优势度和优势种贡献率等生态学指标,同时结合逐步回归分析,讨论了温、盐与浮游动物总丰度变化的关系。结果表明,就四季而言,浮游动物总丰度和盐度呈显著正相关,和温度负相关。而就单个季节而言,除了5月和2月落潮,总丰度和盐度均呈显著正相关,与温度相关关系不显著。调查水域优势种主要为河口半咸水种或近海种。北港的盐度约为0-5, 表现为长江淡水特征;北支的盐度约为12-28,表现为长江径流和外海水团混合水团的特征。上述优势种的盐度适应和水团分布特征决定了长江口浮游动物分布的时空变化,即盐度较高的水域往往有较高的丰度,北支的总丰度和生物量均大于北港。此外,在长江口口内水域,水温较低的枯水期,浮游动物丰度高于水温较高的丰水期,温度的季节波动,以及主要优势种中华华哲水蚤(Sinocalanus sinensis)对低温环境的适应,是调查水域浮游动物总丰度季节变化的重要因素。 另一方面,本论文通过物种多样性、累积优势度曲线等群落水平的指标和相似性检验分析(ANOSIM),对长江口北港和北支浮游动物群落及其主要优势种的差异,以及主要生态因子对浮游动物群落的影响进行了分析。结果表明,北港主要由潮汐影响的淡水和低盐水组成,北支由中、高盐水组成。春季,北港浮游动物丰度和多样性均低于北支,主要优势种为中华华哲水蚤;北支优势种种数较多,主要是真刺唇角水蚤(Labidocera euchaeta)。夏季,北港和北支的多样性较接近,但是种类组成差别较大,北港以中华华哲水蚤和太平洋纺锤水蚤(Acartia pacifica)为主构成河口半咸水群落,北支以由火腿许水蚤(Schmackeria poplesia)、虫肢歪水蚤(Tortanus vermiculus)和太平洋纺锤水蚤等构成河口低盐群落。秋季,北港的丰度和多样性均低于北支,两个水域的群落差异明显,北港主要由中华华哲水蚤构成,北支由小拟哲水蚤(Paracalanus parvus)、针刺拟哲水蚤(Paracalanus aculeatus)、真刺唇角水蚤和中华哲水蚤(Calanus sinicus)等近岸和外海种组成。冬季,两个水域种数和多样性均较低,群落差别达四季最小,中华华哲水蚤占绝对优势。温度和盐度及其相互作用是决定长江口浮游动物群落特征的最主要因素。其中温度是造成研究水域浮游动物群落季节变化的主要因素,而由径流和外海水之间的消长引起的盐度变化是造成北港和北支浮游动物群落区域变化的决定因素。