短颈剑线虫和喜马拉雅剑线虫的形态与rDNA分子特征

描述了日本进境罗汉松根际截获的2种美洲剑线虫:短颈剑线虫Xiphinema brevicollum Lordello et Da Costa,1961和喜马拉雅剑线虫Xiphinema himalayense Ahmad,Lamberti,Rawat,Agostinelli et Srivastava,1998,并对这2种线虫rDNA-ITS和D2D3序列进行了扩增、克隆、测序及系统进化分析.短颈剑线虫和喜马拉雅剑线虫在国家质量监督检验检疫局内首次截获,喜马拉雅剑线虫在日本首次报道,在中国没有分布记载.     

Differential responses of body shape to local and reach scale stream flow in two freshwater fish species

Stream flow is recognised as an important influence on the physical traits, distribution and diversity of stream fishes. However, measures of ‘stream flow’ are not consistent among studies and can refer to variables characterising microhabitat (e.g. flow velocity) or reach‐level (e.g. discharge) parameters. Because of the ambiguity associated with the term ‘stream flow’, the differential effect of these two aspects of local stream hydrology on freshwater fishes is unclear. Using two frequently sympatric freshwater fish species, Etheostoma nigrum and Pimephales notatus, we tested for correlations between population‐level body shape and two measures of stream flow, microhabitat flow velocity (m/s) and reach‐level discharge (m³·s^?1). Etheostoma nigrum body shape was correlated with flow velocity, while P. notatus body shape was correlated with mean annual discharge. The respective correlations are potentially manifestations of behavioural differences among the two species. Etheostoma nigrum is a benthic specialist rarely venturing far from its associated microhabitats. Pimephales notatus is a habitat generalist and uses many different microhabitats but is unable to escape the overall discharge pressures of a particular stream. These results demonstrate the importance of considering the spatial scale of variables when predicting phenotype–environment associations.     

Monitoring fish weight using pulse-echo waveform metrics

Fish anatomical vertical dimensions are extracted from a time-of-flight analysis of fish echo shape using narrow-bandwidth echosounding of swimming individuals. These vertical dimensions fit a Gumbel distribution model and are successfully correlated with fish weight. The proposed method can be used to estimate the mean weight of fish in aquaculture cages as an alternative to target strength measurements. Full-waveform acquisition and signal correlation techniques permitted to increase the signal-to-noise ratio and to improve the performance against traditional envelope-based echosounding.     

几何形态学方法区分短吻鲾地方种群的研究

运用传统形态测量方法和地标点方法对广东阳江和湛江两个短吻鲾的形态特征进行了分析。传统测量方法的主成分分析的前两个主成分（76.29%）能明显地区分出两个种群。相对扭曲主成分分析前3个主成分（64.03%）也能明显地区分出两个种群,但效果差于传统方法的主成分分析。网格变形图显示,两地短吻鲾的形态差异主要表现在头部。地标点法避免了传统的多变量形态测量方法的信息冗余、包含的形状信息不够完整等问题,并能够重建图形,突出局部的形变,能够直观地比较出研究对象之间的细微差别。     

中国大豆胞囊线虫的形态学观察

从辽宁、黑龙江、山东和山西４省６个地点采集大豆胞囊线虫标本，制成雌虫、雄虫、胞囊、阴门锥和２龄幼虫的永久封片，在光学显微镜下进行了形态学的系统观察及电镜扫描，并与日本、美国的大豆胞囊线虫做了形态学比较。我国４省６个地点的大豆胞囊线虫的各个虫态的形态基本相同，与日本、美国的资料基本一致，为同一个种ＨｅｔｅｒｏｄｅｒａｇｌｙｃｉｎｅｓＩｃｈｉｎｏｈｅ．     

Growth performance, morphometric traits and gonad development of induced reciprocal diploid and triploid hybrids between the mud loach (Misgurnus mizolepis Günther) and cyprinid loach (Misgurnus anguillicaudatus Cantor)

Two species of loach, the mud loach (Misgurnus mizolepis Günther) and the cyprinid loach (M. anguillicaudatus Cantor), are commercially important in Korea both for food and ceremonial purposes. The mud loach has superior potential for aquaculture in terms of growth, whereas the cyprinid loach has a more desirable body shape and colour. This study was conducted to produce reciprocal diploid and triploid hybrids and to evaluate their potential benefits in culture by examining growth performance, morphometrics and gonad development. Reciprocal diploid and triploid hybridization was performed by artificial insemination without or with the induction of triploidy. The successful formation of diploid or triploid karyogamy was verified by flow cytometric analysis. Body weights of induced reciprocal diploid hybrids were intermediate between those of the two parental species, i.e. hybrids were heavier than cyprinid loach but lighter than mud loach. In contrast, the growth performance of triploid hybrids was similar to that of their corresponding maternal parents. Diploid hybrids showed intermediate morphometric traits between the two species; however, the body proportions of triploid hybrids were more similar to those of the maternal species than the paternal species. Histological analyses indicated that reciprocal diploid hybrids of both sexes were able to reach maturity, as evidenced by the presence of mature oocytes or spermatozoa in the gonad tissues. However, triploid hybrids showed stringent sterility at the gonadic level; the sizes of ovaries and testes were much smaller, and gonad development was abnormal and significantly retarded.     

Genetic and Phenotypic Diversity in the Graminaceous Cyst Nematode Complex, Inferred from PCR-RFLP of Ribosomal DNA and Morphometric Analysis

Graminaceous cyst nematodes form a group of eleven valid species including Heterodera avenae, Heterodera filipjevi and Heterodera latipons and constitute major pests to cereals. They are widely spread in circum-mediterranean areas where they are presumed to cause yield losses on bread and durum wheat. The objective was to document the diversity of these cereal cyst nematodes, in particular samples from Mediterranean regions, in comparison to species which develop on cultivated or wild grasses (H. arenaria, H. hordecalis, H. mani) and on rice or sugarcane (H. sacchari). Studies involved PCR-RFLP of ITS and morphometrics of the juvenile and cyst characters. UPGMA analysis of molecular data showed that the isolates segregated in two main clusters which seem to represent different evolutionary lineages. The H. avenae sensu lato cluster (I) contained H. arenaria, H. avenae, H. filipjevi and H. mani. The second cluster (II) contained isolates of H. hordecalis and H. latipons. Within H. avenae sensu lato, H. filipjevi was separated from the other related species with significant bootstrap value. The differentiation of H. arenaria, recognized for the first time based on molecular data, and H. mani with few restriction enzymes were the least significant. Intraspecific polymorphism allowed differentiation of isolates originating from Australia within H. avenae sensu stricto. The group H. hordecalis–H. latipons showed the greatest genetic variability between and within isolates. Two representatives of Heterodera sacchari, taxonomically included in the schachtiigrave group, were genetically as distant to this group as to the other graminaceous species belonging to either H. avenae sensu lato or H. hordecalis–H. latipons group. Results inferred from multivariate analysis applied on morphometrics of the cysts and juveniles showed agreement between genetic and phenotypic classifications. This study demonstrates the utility of combined molecular and classical methods to enhance our knowledge about the diversity within the complex of graminaceous cyst nematodes and to establish robust techniques to identify a wider set of nematode species.     

Flight performance and wing morphology in the bat Carollia perspicillata: biophysical models and energetics

Studies on functional performance are important to understand the processes responsible for the evolution of diversity. Morphological trait variation within species influences the energetic cost of locomotion and impacts life history traits, with ecological and evolutionary consequences. This study examined wing morphology correlates of flight performance measured by energetic expenditure in the Seba's short-tailed bat, Carollia perspicillata. In the flight experiments, nature caught bats (59 females, 57 males) were allowed to fly for 3 min in a room. After each flight, thermographic images were taken to measure body temperature, and biophysical models were used to calculate sensible heat loss as a measure of energetic expenditure. Wing morphological traits were measured for each individual and associated with heat loss and power required to fly on performance surfaces. Wing morphological traits explained 7–10% of flight energetic cost, and morphologies with the best performance would save the energy equivalent to 9–30% of total daily requirements. The optimal performance areas within the C. perspicillata morphospace were consistent with predicted selection trends from the literature. A trade-off between demands for flight speed and maneuverability was observed. Wing loading and camber presented sexual dimorphism. These morphological differences are likely associated with more economical but less maneuverable flight in females, leading them to fly more often in open areas along the forest edge. Our findings demonstrate how small scale changes in wing morphology can affect life history strategies and fitness.     

Morphological divergence of the threatened Rocky Mountain sculpin (Cottus sp.) is driven by biogeography and flow regime: Implications for mitigating altered flow regime to freshwater fishes

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