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1.
Seasonal and ontogenetic changes in natural development timewere studied for Eodiaptomus japonicus in Lake Biwa in 1986and 1987. Wild individuals in a certain developmental stagewere collected, fed on natural food and examined until theyhad moulted twice. Natural development times fluctuated irrespectiveof temperature from May to October. Food deficiency delayeddevelopment in all feeding stages, and food availability probablydetermined natural development time. Serious food limitationraised mortality in copepodid stage I. In November developmentwas delayed even with enough food. The development of E.japonicuswas almost isochronal except for a short prefeeding naupliarstage I and a long copepodid stage V. 相似文献
2.
Effects of temperature on life history traits of the dominant calanoid Eodiaptomus japonicus were examined to evaluate its population dynamics in Lake Biwa (Japan). Embryonic and post-embryonic development times and reproduction were determined in the laboratory at four temperatures (10, 15, 20 and 25 °C) and under ad libitum food condition. Post-embryonic development time of E. japonicus from hatching to adult female decreased with increasing temperature from 67.9 to 15.1 days. Males reached the adult stage 1–6 days earlier than the females. Only 15 % of the individuals survived until the adult stage at 10 °C, while 40 % did so at >15 °C. Egg production also depended on temperature. A power function of temperature on instantaneous growth rate predicted a value of <0.06 day?1 when water temperature was below 10 °C, suggesting that E. japonicus retards its growth during winter. The null value obtained at 8.6 °C for the computed population growth rate supports the idea of an overwintering strategy. Responses of life history traits to temperature suggested that in conditions where there was no food limitation, E. japonicus in Lake Biwa would be able to take advantage of the rise of temperature predicted in the context of global climate change. 相似文献
3.
Y. Ranga Reddy 《Hydrobiologia》1992,231(1):1-11
Eodiaptomus shihi n. sp. is described from the material collected from Gandhisagar reservoir, River Narmada and a hillpool in the Madhya Pradesh State of central India. The salient features of this new species include: in female, the left metasomal wing is strongly developed, and the endopodite in leg 5 is 2-segmented and longer than first exopodite-segment; in male, the right caudal ramus is armed with a tooth-like chitinous structure near ventro-distal region, and in right leg 5, the basis is devoid of any hyaline lobe on inner margin and the first exopodite-segment is produced into a large spinous process at disto-outer corner. 相似文献
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The pelagic copepod Acartia clausi Giesbrecht was bred 3 times from nauplius stages I and II to maturity at 5, 10, 15 and 20 °C and 4 different rations of autotrophic and heterotrophic food. The rate of development of copepods increased with increasing temperature and food level. At the highest food level the stage duration was almost constant through most stages, but development was not quite isochronal. Particularly at lower food concentrations stage duration became progressively longer with increasing stage of development. The relation between development time and temperature is described by Blehrádek's functions at different food levels. These relations predict a generation time of about 50 days at spring bloom conditions and only slightly less during summer due to food limitation. Comparison with estimates in the field from the literature suggests hat food is often limiting during summer conditions. 相似文献
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7.
Aspects of the female genital segment with and without attached couplers and enclosed spermatophores are studied of Gaussia specimens collected in the SW Atlantic and SE Pacific. A new species found in the SW Atlantic, Gaussia asymmetrica, is proposed. 相似文献
8.
We carried out a complete study of oogenesis in Centropages typicus using structural, ultrastructural and cytochemical data. The usual stages of oogenesis, i.e. germinative phase, premeiosis, primary and secondary vitellogenesis, were found. The latter two stages were the most typical. Primary vitellogenesis consisted of endogenous yolk accumulations; these substances, probably of lipoprotein or lipoglycoprotein nature, were produced at the granular endoplasmic reticulum level and then stocked in the reticulum cavities. During secondary vitellogenesis, endogenous yolk production continued, but we mainly observed the development of exogenous yolk accumulation (lipid droplets and protein globules) in the ooplasm. These accumulations resulted from the fusion of very numerous pinocytotic vesicles arising from the oolemma and containing substances probably brought to the oocytes by the hemolymph. The effect of various proteases on the vitellus globules caused a more or less marked digestion of their contents, tending to prove their protein nature. The end of vitellogenesis was marked by the appearance of vacuolar formations with dense lamellae which could correspond to cortical granules. 相似文献
9.
The complete postembryonic development of Tropodiaptomus informiscomprises six naupliar and six copepodid stages of which thelast is the adult. Of all the characteristics, it is the shapeand number of setae on the terminal segments of the antennulesin the late naupliar stages, and the shape and setae of exo-and endopods of the fifth legs from copepodids III to V whichare most useful in constructing relationships among eight diaptomidsreared. 相似文献
10.
This study represents the first attempt to acquire basic informationon the feeding, reproduction and development of the copepodClausocalanus furcatus. This small oceanic calanoid benefitsfrom low phytoplankton concentrations and has a swimming behaviourwhich differs dramatically from that of other small copepods.Our preliminary results may be indicative of the success ofthis species in oligotrophic waters. 相似文献
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Jimenez-Melero Raquel; Parra Gema; Souissi Sami; Guerrero Francisco 《Journal of plankton research》2007,29(6):553-567
Ephemeral and semi-permanent saline wetlands undergo frequentunpredictable disturbances such as episodes of high salinityor desiccation. Organisms living in these systems are adaptedto survive and develop in very fluctuating and unpredictableconditions and, therefore, could help us to understand lifecycle strategies and plasticity in the context of global warming.Arctodiaptomus salinus is a common species occurring in suchenvironments and is often the main constituent of their zooplanktoncommunity, which is characterized by low diversity and shorttrophic webs. Despite the qualitative and quantitative importanceof A. salinus in these systems, no attention has been paid tothe effect of temperature on its population dynamics. For thisreason, variability in post-embryonic development times andstage-specific mortality of A. salinus were studied for thetemperature-range over which this species occurs. Mortalitywas higher in earlier naupliar and first copepodite stages.The highest developmental variability and mortality occurredat the highest temperature. Developmental instability couldexplain the high variability at high temperatures and the fluctuatingspeed of development throughout the successive stages. The interactionbetween mortality and developmental variability might be animportant mechanism ensuring persistence of A. salinus populationsin these fluctuating and stressing environments. 相似文献
13.
The geographic distribution of the bathypelagic calanoid genus Paraeuchaeta was investigated by examining midwater trawl and plankton net samples collected mostly from depths exceeding 1000 m throughout the world's oceans. Of the 81 species referred to Paraeuchaeta, the geographic ranges of about 50 species could be defined with reasonable certainty. Contrary to early authors, the number of species having a worldwide distribution was surprisingly small (12 species or 15% of the 81 species of the genus) as compared to common species endemic to various geographic regions (34 species or 42% of the total of 81). Almost twice as many species were found in the Indo-Pacific Ocean as in either the Atlantic or the Southern Ocean. Faunistically, the northern Atlantic, mid-Atlantic, northern Pacific, East Pacific, Indo-West Pacific, and Southern Ocean were distinct in terms of endemic species. A number of species were found to be endemic to highly productive areas, where they were usually very abundant. Rare species, on the other hand, were generally found to be widely distributed, although some were too rare for their range to be determined with certainty. To explain these findings, the following hypothesis is proposed: Bathypelagic calanoids endemic to and abundant in eutrophic areas are those adapted to eutrophic conditions of their habitats and therefore cannot expand their ranges into contiguous oligotrophic waters even if the other environmental conditions are favorable. Other species, on the other hand, generally have extensive geographic ranges because of their survival ability in widely expanding oligotrophic conditions and the absence of physicochemical barriers at bathypelagic depths of the world's oceans. 相似文献
14.
All the postembryonic developmental instars of Neodiaptomus lindbergi Brehm, 1953, reared in the laboratory from eggs, are described and illustrated. Further, the larval affinities of this species vis-a-vis certain other Indian diaptomid species are mentioned. 相似文献
15.
Of the nine species of Tropodiaptomus occurring in Equatorial East Africa, seven are redescribed and figured in great detail. Their relationships are discussed. A primary homonym is eliminated, and types are indicated wherever possible. 相似文献
16.
The species composition of copepods of the genus Pseudocalanusthat dominate the zooplankton in Avachinskaya Bay was studied from samples collected in 1988. Three species were identified: P. minutus(Kröyer), P. newmani(Frost), and P. acuspes(Giesbrecht). The latter species is the first record for the fauna of the northwestern Pacific Ocean. Synonymy and original figures are given; the seasonal variations in the morphometric features and characteristics of Pseudocalanusare discussed. 相似文献
17.
Blanco-Bercial L Bradford-Grieve J Bucklin A 《Molecular phylogenetics and evolution》2011,59(1):103-113
The order Calanoida includes some of the most successful planktonic groups in both marine and freshwater environments. Due to the morphological complexity of the taxonomic characters in this group, subdivision and phylogenies have been complex and problematic. This study establishes a multi-gene molecular phylogeny of the calanoid copepods based upon small (18S) and large (28S) subunits of nuclear ribosomal RNA genes and mitochondrial encoded cytochrome b and cytochrome c oxidase subunit-I genes, including 29 families from 7 superfamilies of the order. This analysis is more comprehensive than earlier studies in terms of number of families, range of molecular markers, and breadth of taxonomic levels resolved. Patterns of divergence of ribosomal RNA genes are shown to be significantly heterogeneous among superfamilies, providing a likely explanation for disparate results of previous studies. The multi-gene phylogeny recovers a monophyletic Calanoida, as well as the superfamilies Augaptiloidea, Centropagoidea, Bathypontioidea, Eucalanoidea, Spinocalanoidea and Clausocalanoidea. The phylogeny largely agrees with previously-published morphological phylogenies, including e.g., enlargement of the Bathypontioidea to include the Fosshageniidae. 相似文献
18.
The freshwater Calanoida (Crustacea: Copepoda) of Thailand 总被引:3,自引:3,他引:0
14 Species of freshwater Calanoida in Thailand are reported in this study. The most common species is Neodiaptomus botulifer. Most of these belong to the Southeast Asian species, the remainder are either Indian or East Asian copepods. The zoogeographical demarcation of copepods in Thailand is not very distinct due to its interconnecting riverine and reservoir systems as well as frequent flood. The peculiarity of the Thai Calanoida and their distribution is discussed in a Southeast Asia context. A taxonomic key to the Thai Calanoida is formulated. 相似文献
19.
Macrozooplankton may affect algal and microbial plankton directly through grazing or predation and indirectly through nutrient regeneration. They may also affect potential prey positively by removing alternative predators. Here, we examined the effects of a cladoceran (Daphnia) and a calanoid copepod (Eodiaptomus) on algal and microbial plankton in a Japanese lake using in situ experiments in which we manipulated the nutrient supply and biomass of these macrozooplankton. The response of algal and microbial plankton to macrozooplankton was diverse and varied depending on the level of nutrient supply. Eodiaptomus seemed to feed mainly on large algae (>20 µm) and microzooplankton, while direct grazing by Daphnia on algae, bacteria, heterotrophic nanoflagellates (HNF), and microzooplankton (ciliates, heliozoa, and rotifers) was pronounced. Trophic linkages within these microbial plankton was also suggested; bacteria were grazed by HNF and these in turn were grazed by microzooplankton. When the nutrient supply was high, both HNF and microzooplankton were exposed to higher amounts of algae and lower bacterial abundance. Moreover, nutrient regeneration by daphnids and Eodiaptomus copepods seemed to differentially stimulate the growth of algae and bacteria. The results suggest that the relationship between macrozooplankton and microbial plankton cannot be fully understood without taking into consideration not only the feeding characteristics of the macrozooplankton, but also the food web structure, the subsidized algal resource, and nutrient regeneration from the macrozooplankton. 相似文献
20.
All the postembryonic developmental instars of Phyllodiaptomus blanci (Guerne & Richard, 1896), reared in the laboratory, are described and illustrated. The larval affinities of this species
vis-a-vis certain other diaptomid species are mentioned. 相似文献