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1.
Population dynamics and production of C. luctuosa were compared in two reaches of the Agüera stream (northern Spain). This species showed univoltine winter life history in both sites. However, the start of the recruitment period, and the cohort production interval differed in 1 month between reaches. Secondary production of C. luctuosa ranged from 76 mg m–2 year–1 (upper site) to 93 mg m–2 year–1 (lower site). Although annual production seemed to be mainly influenced by the biomass found at each site, changes in life history may have also been important. The need to have accurate information about life history of the analysed species at the study sites when assessing secondary production is highlighted.  相似文献   

2.
The larvae of Caenis (Caenidae) and Tricorythodes (Tricorythidae), once considered to be confamilial, have notable morphological and behavioural similarities. Univariate and multivariate (discriminant analysis) techniques were used to determine which environmental variables best characterized the larval habitats of Caenis and Tricorythodes at 40 sample sites on 29 rivers within the Interior Plains of Alberta, Canada. River width, depth and substrate type distinguished riverine habitats of the two genera. Larvae of Tricorythodes occurred in wide rivers of varying depths that possessed coarse substrates. Although larvae of Caenis occurred in a variety of habitats, they were found more frequently on stable substrates in narrow, deep rivers.  相似文献   

3.
中国香港细蜉属三新种记述(蜉蝣目:细蜉科)   总被引:1,自引:0,他引:1  
记述了采自中国香港的细蜉科Caenidae,细蜉属Caenis3新种:点刻细蜉Caenis aspera sp.nov.、双突细蜉Caenis bicornis sp.nov.和光滑细蜉Caenis lubrica sp.nov.。模式标本均保存在中国广州华南农业大学昆虫学系昆虫标本室。  相似文献   

4.
Knowledge of the mayfly biodiversity in the Balkan Peninsula is still far from complete. Compared to the neighbouring countries, the mayfly fauna in Croatia is very poorly known. Situated at the crossroads of central and Mediterranean Europe and the Balkan Peninsula, Croatia is divided into two ecoregions: Dinaric western Balkan and Pannonian lowland. Mayflies were sampled between 2003 and 2013 at 171 sites, and a total of 66 species was recorded. Combined with the literature data, the Croatian mayfly fauna reached a total of 79 taxa. Of these, 29 species were recorded for the first time in Croatia while 15 species were not previously recorded in Dinaric western Balkan ecoregion. Based on the mayfly assemblage, sampling sites were first structured by ecoregion and then by habitat type. In comparison with the surrounding countries, the Croatian mayfly fauna is the most similar to the Hungarian and Bosnian fauna. Some morphologically interesting taxa such as Baetis cf. nubecularis Eaton, 1898 and Rhithrogena from the diaphana group were recorded. Ephemera cf. parnassiana Demoulin, 1958, the species previously recorded only from Greece, was also recorded.  相似文献   

5.
我国大陆细蜉属Caenis共知5种,其中短铗细蜉Caenis parviforcipis(Zhou et al.)n.comb.由短尾蜉属Brachycercus转移而来;中华细蜉Caenis sinensis Gui et al.稚虫形态在本文中首次描述;另外从标本来看,已知的黑铗细蜉Caenis nigroforceps Zhou et al.实际为近岸细蜉Caenis rivulorum Eaton的新异名;本文描述1新种:花斑细蜉Caenis melanoleuca,sp.nov.;第5种黑点细蜉Caenis nigropunctata Klapalek也根据标本得到了确认。文中还给出了以上5种成虫和4种稚虫的检索表。所有标本都保存在南京师范大学生命科学学院。  相似文献   

6.
We conducted a field survey for flatworms to select species as potential biological control agents against Aedes aegypti and Culex pipiens (Diptera, Culicidae) breeding in artificial containers. Laboratory experiments were performed to determine the daily predation rate, differential predation on each mosquito larval instar, selective predation on either A. aegypti or C. pipiens, and predator tolerance to water from artificial containers. Girardia anceps (Tricladida, Paludicola, Dugesiidae), Mesostoma ehrenbergii and Bothromesostoma cf. evelinae (Rhabdocoela, Typhloplanoida, Typhloplanidae) were found in temporary puddles and permanent pools. In the laboratory, they killed between 52% and 100% of immature mosquitoes coexisting in the same habitat. No preference of flatworms for mosquito preys was detected. Predation rate was related to predator size and instar of preys. Girardia anceps and B. evelinae survived after a dry period and when re-flooding occurred, they laid eggs. Tolerance to water from artificial containers was highest in G. anceps and this species could be a suitable predator to reduce mosquito populations from artificial containers using an inoculative approach.  相似文献   

7.
Three species of Tetraploa collected from Sasa, or bamboos, are described and illustrated. Among them, T. curviappendiculata on Sasa kurilensis and T. longissima on Pleioblastus chino are compared with hitherto known species and described as new species. In the nomenclature, T. javanica is substituted for T. biformis, formerly reported from the dead bark of a broad-leaved tree in Japan, as a correct name.  相似文献   

8.
The ecology of Potamanthus myops (Potamanthidae) was examined for a one year period in a central Michigan fourth order stream. Lowest nymphal densities (4.7 m-2) occurred in mid-summer after adult emergence, while highest densities were found during late summer and fall (68.0 m-2 and 66.2 m-2) after the new cohort had hatched. Biomass was the inverse of density with highest values, 67.7 mg m-2, just prior to peak adult emergence in June and lowest in late summer (16 mg m-2). Nymphs maintained a contagious spatial distribution with k values ranging between 0.19 and 1.40. P. myops nymphs fed mostly on detritus (96.8%), placing them in the collector-gatherer functional group. Nymphs were always found in erosional zones associated with rock substrate. Nymphs used their mandibular tusks for positioning themselves beneath rocks, while also appearing to use them for defensive purposes.  相似文献   

9.
Summary In a mature, even aged stand of mixed chaparral, Rhus laurina (facultative resprouter) had consistently higher water potentials and deeper roots than Ceanothus spinosus (facultative resprouter) and Ceanothus megacarpus (obligate seeder). For two years following a wildfire, the same stand of chaparral had resprouts with higher survivorships, predawn water potentials, stomatal conductances, photosynthetic rates and shoot elongation rates than seedlings. Supplemental irrigation of seedlings during summer months removed differences between resprouts and seedlings suggesting that the cause of such differences was limited water availability to the shoot tissues of seedlings. After two years of postfire regrowth, mean seedling survivorship for the obligate seeder (C. megacarpus) was 42%, whereas seedling survivorship for facultative resprouters was only 18% (C. spinosus) and 0.01% (R. laurina). Our results are consistent with the hypothesis that lack of resprouting ability among obligate seeders is offset by an enhanced ability to establish seedlings after wildfire, allowing obligate seeders to maintain themselves in mixed populations through many fire cycles.  相似文献   

10.
记述采自中国四川省的菜花露尾甲属菜花露尾甲亚属1新种:淡翅菜花露尾甲Meligethes(Meligethes)pallidoelytrorum Chen&Kirejtshuk sp.nov.。对其特征作了描述,提供了成虫形态及雌雄外生殖器特征图。新种的主要鉴别特征为:虫体背部体表光滑,鞘翅具稀疏的刻点,跗爪基部具明显的齿。并提出滑菜花露尾甲M.(M.)lutra Solsky,1876和蜜菜花露尾甲M.(M.)melleus Grouvelle,1908是长唇菜花露尾甲M.(M.)vulpes Solsky,1876的新异名。  相似文献   

11.
The taxonomic status of three rarely captured, nominal species of Indo-Pacific symphurine tonguefishes,Symphurus trifasciatus (Alcock, 1894),S. microrhynchus (Weber, 1913), andS. holothuriae Chabanaud, 1948, is resolved.Symphurus microrhynchus, previously known only from three specimens, is redescribed based on 12 specimens.Symphurus holothuriae, previously reported only from the holotype, is a junior subjective synonym ofS. microrhynchus. Symphurus trifasciatus is redescribed based on six specimens, including the lectotype designated in this study.Symphurus microrhynchus is distinguished from congeners by a combination of meristic features, head and opercle shape, dorsalfin position, and features of its pigmentation. The species occurs in relatively shallow tropical waters from Zanzibar through French Polynesia (the only reported occurrence of a shallow-waterSymphurus from a locality on the Pacific Plate), including Indonesia, Papua New Guinea, Vietnam, and northwestern Australia.Symphurus trifasciatus, known from deep waters along both coasts of the Indian subcontinent and adjacent waters, has an overall similarity in body shape and meristic features reminiscent of those inS. microrhynchus, but differs notably in having a longer and wider head, a distinctive opercle shape, number of scale rows on the head, and pigmentation pattern.  相似文献   

12.
New combinations for three species ofPolypleurum have been proposed. The Apinagia type of embryo sac is recorded for the first time in a species ofPolypleurum, P. filifolium. The Dicraea type of embryo sac found inP. dichotomum andP. munnarensis has been reinterpreted and renamed as the Polypleurum type. The embryo sac types met with in the family are discussed. The nucellar plasmodium organizes before the embryo sac attains maturity in all the three investigated species.  相似文献   

13.
The distribution of CHy-banded heterochromatin was studied in the chromosomes ofAegilops longissima, Ae. speltoides, Triticum monococcum, andT. turgidum. Interphase nuclei were measured after Feulgen staining at different thresholds of optical density; the curves so obtained indicated the relationship among the species with respect to the different fractions of the genomic DNA. The karyological and cytophotometric analyses indicate differences betweenAe. speltoides andAe. longissima, the latter species being enriched in heterochromatin. Similar results were demonstrated for the genusTriticum, in whichT. turgidum showed more heterochromatin when compared withT. monococcum. The results suggest that the B genome of the cultivated wheats possesses a type of heterochromatin that resembles the type present inAe. longissima.  相似文献   

14.
Seed protein electrophoresis confirms the existence of polymorphism among hexaploid populations ofFestuca arundinacea. Both protein and morphological results suggest thatF. pratensis andF. arundinacea should retain independent specific status. High protein homology of these two species withF. gigantea points towards phylogenetic links between these taxa.  相似文献   

15.
分布在我国西南地区的横坑切梢小蠹,云南切梢小蠹和短毛切梢小蠹同域危害寄主云南松,给林业生产带来巨大损失。为探讨同域切梢小蠹种群在共存下对其空间分布格局的影响,采用传统聚集指标法和地统计学方法研究了三者在梢转干期不同受害云南松纯林树冠中的空间分布型。结果表明重度受害样地中云南切梢小蠹种群密度显著高于横坑切梢小蠹,在轻度受害样地则相反;传统聚集指标法结果显示同域共存的3种切梢小蠹种群在不同受害程度云南松中均为聚集分布,横坑切梢小蠹和云南切梢小蠹聚集是由环境因素和昆虫本身的聚集习性引起;地统计学结果表明除重度受害样地中短毛切梢小蠹呈随机分布外,其余切梢小蠹在不同种群密度下均呈聚集分布;除重度受害样地横坑切梢小蠹外,其他小蠹的空间依赖范围为4.01—7.45 m。横坑切梢小蠹和云南切梢小蠹在不同受害林分中拟合的半变异函数模型在球形模型和高斯模型之间转换。同域共存关系不影响不同种群密度下的切梢小蠹种群空间分布类型,但影响其半变异函数模型和理论参数。  相似文献   

16.
DistylousLinum grandiflorum, L. mucronatum, andL. pubescens have dimorphic pollen grains. In short-styled flowers the exine has monomorphic processes each with a ring of papillae. In long-styled flowers the exine has two types of processes: small processes terminating in a spinule and larger processes with a central spinule surrounded by a ring of spinuels, papillae or buttresses. The distylousLinum species of four different sections, in which morph-specific differences in the wall structure of stigmatic papillae have been reported, also exhibit exine dimorphism. The patterns of these dimorphisms are similar in all four sections in which distyly is present.  相似文献   

17.
When electrophoretic profiles of native proteins from vegetative mycelia ofPhytophthora palmivora, Phytophthora capsici and Phytophthora citrophthora causing black pod disease of cocoa in India were compared on a single Polyacrylamide gel, the isolates of same species were readily distinguished both qualitatively by visual similarity in banding patterns and quantitatively by calculating similarity coefficients. Similarity coefficients were generally much higher between isolates within a species than between isolates of different species. The dendrograms obtained after unweighted pair grouping with arithmetic averaging cluster analysis, revealed that all the isolates ofPhytophthora capsici were highly homogenous and formed a single cluster. The isolates ofPhytophthora citrophthora were resolved into two electrophoretic types which were clustered into two distinct sub groups.Phytophthora palmivora formed a separate group. Thus, the results reveal that polyacrylamide gel electrophoresis can be used successfully in distinguishing species and sub groups within a species ofPhytophthora encountered on cocoa. CPCRl contribution No. 914.  相似文献   

18.
Three jars from the Hamburg Museum contained specimens of Branchiobdella minuta, presumably from the original Pierantoni (1912) material, and Cirrodrilus cirratus and C. uchidai from Yamaguchi's (1932a) collection. The head of a syntype of B. minuta was described and B. cheni becomes its junior subjective synonym. One specimen each of C. cirratus and C. uchidai was sectioned and described, particularly the male genitalia. The diet of all three branchiobdellids consists of microorganisms. In Cirrodrilus sp. basic protein granules were demonstrated in the gland cells of the intestine and its chloragogen cells. The peristomial and lateral epidermal gland cell secretions were characterized histochemically.  相似文献   

19.
Chromosome banding patterns obtained with C- and N- banding, and AgNO3 staining were studied in somatic metaphase complements of fourLactuca species.L. sativa andL. serriola have almost identical chromosome morphology, andL. saligna differs only slightly from them, butL. virosa is quite distinct from the other species. A gross comparison of the banded karyotypes suggests a closer relationship ofL. saligna toL. sativa/serriola than toL. virosa. Our data agree with the results of previous crossing experiments in these species but conflict partly with recent RFLP data which indicate a closer phenetic relationship ofL. saligna toL. virosa than toL. sativa/serriola. Such a discrepancy may be explained assuming that domestication ofL. sativa/serriola resulted in an increased selection pressure on unique DNA sequences as demonstrated by the RFLP data. Differential evolution of specific heterochromatin classes (and presumably of highly repetitive DNA classes), as revealed by chromosome banding techniques was not linked to domestication. Thus the disparity in conclusions about relationship (in terms of genetic similarity) as based on the different experimental approaches reflects a non-parallel evolution of highly repetitive vs. unique DNA classes.  相似文献   

20.
This work is a continuation of electrophoretic investigations aimed at revealing a wild relative ofVicia faba. Electrophoretic analysis (PAGE) of seed albumins covered 52 accessions representing eightVicia species of sect.Hypechusa and two species of sect.Peregrinae. Most of the examined species showed an intraspecific variation due to differences between accessions and/or individual variation within accessions. In spite of the intraspecific variation, marked interspecific differences were recorded. However, none of the investigated species displayed electrophoretic seed albumin patterns similar to those reported earlier forV. faba. Contribution of the obtained results to characterization of the examined taxa is discussed.  相似文献   

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