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Registros recuperados: 12
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A demographic study of the life cycle of <i>Tisbe furcata</i> (Baird, 1837) (Copepoda: Harpacticoida) OMA
Bergmans, M..
The life-cycle of the harpacticoid copepod <i>Tisbe furcata</i> (Baird, 1837) at 18°C was studied quantitatively. Stage durations were determined by two different methods, using synchronous cohorts. Combined nauplius stages last for 80.4h; the successive copepodite stages take 23.0, 23.2, 28.0 (females) to 23.2 (males), 33.4 (females) to 24.2 (males) and 48.8 (females) to 34.7 (males) h, respectively. Females develop more slowly but more synchronously than males. Age-specific survival and fertility rates were used to calculate the stable stage distribution in an exponentially growing population. From life-table data the following demographic parameters were computed: intrinsic rate of natural increase...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Life cycle Tisbe furcata (Baird; 1837) ANE; Belgium; Oostende; Sluice Dock.
Ano: 1981 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3705
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An <i>r</i>-strategist in Antarctic pack ice OMA
Bergmans, M.; Dahms, H.-U.; Schminke, H.K..
The Antarctic copepod <i>Drescheriella glacialis</i>, an inhabitant of sea ice, is the first polar invertebrate metazoan to have been cultured throughout its life cycle. We describe its demographic characteristics on the basis of a laboratory cohort study and correlative field data. When compared to its closest temperate zone relatives, <i>D. glacialis</i> shows temperate compensation of developmental and reproductive rates. A genuine <i>r</i>-strategist in every respect, it does not fit established trends for Antarctic invertebrates but appears well adapted to the peculiar spatio-temporal variability.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Polar waters Population structure Reproduction Reproductive cycle Sea ice Temperature effects Copepoda [copepods] Drescheriella glacialis PS; Antarctica PSW; Weddell Sea.
Ano: 1991 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3111
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Competition between the sibling species <i>Tisbe holothuriae</i> and <i>T. battagliai</i> (Harpacticoida) OMA
Bergmans, M.; Janssens, P.P.M..
The influence of the salinity on the performance of the sibling species <i>Tisbe holothuriae</i> and <i>T. battagliai</i> in pure and mixed cultures was studied, using laboratory stocks adapted to 32 pro mille for over 175 generations. Cohort studies show that <i>T. holothuriae</i> has higher growth rates (R<sub>0</sub> and r) at 32 pro mille, <i>T. battagliai</i> at 20 pro mille. The latter's life cycle is much less affected by the difference in salinity. 'De Wit' replacement series were used to study competitive interactions. Without water renewal, <i>T. holothuriae</i> eliminates its sibling species in less than 2 generations, apparently through chemical interference. With water...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Competition; Growth; Marine crustaceans; Phenology; Salinity; Sexual reproduction; Sibling species; Tisbe battagliai; Tisbe holothuriae.
Ano: 1988 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3121
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Critique of some practices in life-history studies, with special references to harpacticoid copepods OMA
Bergmans, M..
Published studies on the demography and reproductive strategies of harpacticoid copepods are examined critically. At the technical level, the popular approximation <i>r</i> = ln R<sub>0</sub>/T<sub>c</sub> is shown to be inappropriate as an estimate of the intrinsic rate of increase of harpacticoids. It leads to a systematic underestimation, by 8-29%, for life histories typical of fast-breeding species. Various <i>ad hoc</i> variants of <i>r</i> and <i>R<sub>0</sub></i> calculations occurring in the literature are also criticized. At the conceptual level, a more discriminating approach to life-history characteristics is necessary; this applies both to the assessment of...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Life history; Copepoda [copepods].
Ano: 1984 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3311
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Differential food preferences in three co-occurring species of <i>Tisbe</i> (Copepoda, Harpacticoida) OMA
Vanden Berghe, W.; Bergmans, M..
Killed samples of a monoclonal bacterial strain and an axenic alga were offered in different proportions to <i>Tisbe holothuriae, T. battagliai</i> and <i>T. furcata</i>. Incorporation of carbon ranged from 0.05 and 0.39 µg C (adult male)<sup>-1</sup> d<sup>-1</sup>. Using a radiolabelling technique, the ratio in which the two food types were assimilated was compared to the ratio in which they were offered. Neither <i>T. holothuriae</i> nor its sibling species fed selectively under our conditions, but <i>T. furcata</i> showed a clear preference for bacteria. These findings constitute the first evidence for intrageneric dietary differentiation in harpacticoids. The results of the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Food preferences Tisbe battagliai Tisbe furcata (Baird; 1837) Tisbe holothuriae.
Ano: 1981 URL: http://www.vliz.be/imisdocs/publications/100832.pdf
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Distribution and adaptations of sea ice inhabiting <i>Harpacticoida</i> (Crustacea, Copepoda) of the Weddell Sea (Antarctica) OMA
Dahms, H.-U.; Bergmans, M.; Schminke, H.K..
Seven harpacticoid species were found to be associated with sea ice collected during 5 Antarctic cruises of the <i>RV Polarstern</i>. Their distribution within the fast ice and pack ice zones of the Weddell Sea is presented. Whereas some individuals probably become entrapped into the ice only accidentally, at least 4 species are genuinely sympagic. These have evolved remarkable adaptations, as evidenced by field and laboratory studies of <i>Drescheriella glacialis</i>, which is by far the most abundant. Such adaptations include: the ability to penetrate deep into ice; a comparatively high salinity tolerance allowing it to endure large salinity fluctuations associated with ice crystal formation and melting; good swimming ability,...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Biogeography Dormancy Ecology Life history Salinity tolerance PSW; Weddell Sea.
Ano: 1990 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3067
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Life history adaptation to demographic regime in laboratory-cultured <i>Tisbe furcata</i> (Copepoda, Harpacticoida) OMA
Bergmans, M..
A laboratory population of <i>Tisbe furcata</i> (Copepoda, Harpacticoida) with a 35-generation history of stable population size was examined for life history adaptations to demographic stationarity. Survival and fecundity schedules and individual fitness parameters were measured; a standard being provided by three accessions of the wild source population. <i>Tisbe furcata</i> responded to density regulation by increasing its potential net reproductive rate, R<sub>o</sub> This result is in agreement with the theory of fitness in age-structured populations, though in contradiction with intuitions based on the <i>r-K</i>paradigm. The physiological mechanisms through which R<sub>o</sub> is raised are...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Laboratory culture Life history Tisbe furcata (Baird; 1837).
Ano: 1984 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3313
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On the need for independently estimating organic tripton carbon content OMA
Pissierssens, P.; Bergmans, M.; Polk, Ph..
A method is described by which the contribution of Non-Living Particulate Organic Matter (NLPOM) to Total Organic Matter can be determined. The dye Trypan Blue stains only dead organic matter. The surface of the stained particles is used as an indirect measure of the NLPOM-carbon content. Applying this method, it is shown that the bivariate linear regression of POM on chlorophyll <i>a</i> may produce serious errors in the calculated NLPOM contribution when carbon which is neither tripton- nor chlorophyll-related is present in appreciable quantities.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Analytical techniques; Carbon compounds; Organic matter; Staining.
Ano: 1985 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3283
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Postembryonic development of <i>Tisbe gracilis</i> (T. Scott) (Copepoda, Harpacticoida) OMA
Dahms, H.-U.; Bergmans, M..
All six naupliar and five copepodite stages of <i>Tisbe gracilis</i> (T. Scott, 1985) are described. A key for the identification of the nauplius stages is given. The oral appendages of all copepodite stages are described. Sexual dimorphism is visible from the copepodite IV stage on.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Tisbe gracilis (T. Scott; 1895).
Ano: 1988 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=2988
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Taxonomic notes on species of <i>Tisbe</i> (Copepoda, Harpacticoida) from a Belgian sluice dock OMA
Bergmans, M..
<i>Tisbe furcata, T. gracilis, T. holothuriae</i> and <i>T. battagliai</i> are reported from the Sluice Dock near Ostend (Flemish Coast). The latter three species are new to the Belgian fauna. A cross-breeding experiment between strains of <i>T. holothuriae</i> from Ostend and Venice (Italy) conforms perfect interfertility and hybrid F<sub>1</sub> heterosis. <i>T. furcata</i>, the "stumbling block" of the genus, is described and an account is presented of the characteristics and ontogeny of its colour pattern.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Brackishwater environment New records Shallow water Taxonomy Tisbe battagliai Tisbe furcata (Baird; 1837) Tisbe gracilis (T. Scott; 1895) Tisbe holothuriae Tisbe Lilljeborg; 1853 ANE; Belgium; Oostende Harbour; Sluice Dock.
Ano: 1979 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3622
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Waterboatmen, and testing for Lotka-Volterra-type interactions OMA
Bergmans, M..
A previous paper by Istock, in which this author claims to have successfully applied the Lotka-Volterra model to his observations on corixid population dynamics, is criticised for the shortcomings in evidence cited to support the model's fit with the data. It is contended that the dynamic behaviour of the system of Hesperocorixa lobata - Sigara macropala interaction is not in accordance with the Lotka-Volterra model. ThIs brief critique is followed by comments by istock in reply to the points raised in Bergmans' letter.
Tipo: Info:eu-repo/semantics/article Palavras-chave: Models; Population dynamics; Corixidae.
Ano: 1979 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3600
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When <i>m</i>-selection? OMA
Bergmans, M..
Caswell and Hastings (1980) introduced an explicit model for the relative merits, in terms of growth rate <i>lambda</i>, of developmental shifts vs. fecundity increases. Some aspects of their model are clarified by concentrating on the (fitness >1) half-plane rather than on the (accelerated reproduction) half-plane. There is no strict equivalence between Caswell and Hastings' key parameter <i>lambda/P</i> and the dynamic behaviour of the population which is governed by <i>lambda</i>. Thus in some stationary/declining populations time shifts of reproduction (forward or backward, according to the value of <i>lambda/P</i>) are just as effective in promoting a high <i>lambda</i> as they are in...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Population parameters.
Ano: 1983 URL: http://www.vliz.be/nl/open-marien-archief?module=ref&refid=3364
Registros recuperados: 12
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