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| Registros recuperados: 12 | |
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| 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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| 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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| 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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| 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 |
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| Registros recuperados: 12 | |
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