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  • 1995-1999
  • 1985-1989  (1)
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  • 1989  (1)
  • 1982  (2)
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  • 1995-1999
  • 1985-1989  (1)
  • 1980-1984  (2)
  • 1975-1979
  • 1970-1974
Year
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 12 (1982), S. 0 
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. The oxidation of 2, 5-diniethylfuran (DMF) to cis-1, 2- diacetylethylene (DAE) is a specific test for singlet oxygen (1O2). A method has been developed for the measurement of DAB by direct injection gas chromatography. By the use of this method, the photochemical generation of 1O2 has been demonstrated in samples of two Canadian humic waters.Two other photochemical reactions probably mediated by 1O2generation, the oxidation of histidine and the inactivation of a-chymotrypsin, have been demonstrated in these waters.The possible ecological and environmental implications of these findings are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 50 (1989), S. 209-214 
    ISSN: 1570-7458
    Keywords: Demography ; male population biology ; sex ratio ; Tetranychus urticae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé La reproduction est un processus qui nécessite généralement un mâle et une femelle. Cependant la biologie des populations ne s'est traditionnellement intéressée qu'à la contribution des femelles dans ce processus. Un effet de cet accent sur les femelles est que l'activité reproductrice des mâles a été très ignorée. Cet article examine, dans un contexte démographique, l'activité reproductrice des mâles de T. urticae, acarien arrhénotoque et phytophage. Trois séquences de l'activité reproductrice des mâles ont été examinées: 1) la copulation, 2) l'insémination, 3) la reproduction. En moyenne un mâle de 1 jour a copulé 15 fois, inséminé 15 femelles et a eu 336 filles. Pendant les 8 premiers jours, le mâle moyen a inséminé 70 femelles et a eu 1145 filles. Ces résultats suggèrent que le nombre de spermatozoïdes transférés à chaque insémination, plus que le nombre d'inséminations, est le facteur limitant d'une forte contribution du mâle à la reproduction.
    Notes: Abstract This paper determines reproductive limits and variation in performance of male twospotted spider mites Tetranychus urticae Koch when virgin females are provided ad libitum over the first eight days of adult life. Theree phases of male reproduction were studied: copulations, insemination and reproduction. An average one day old male copulated 15 times, inseminated 15 females, and contributed to 336 daughters. All parameters declined with age. The average male inseminated 70 females and contributed to 1145 daughters in the first days. Variability between males was small for all parameters considered. These data suggest that the number of sperm transferred at each insemination, rather than the number of inseminations, is the limiting step to higher male reproductive output.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 52 (1982), S. 389-395 
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A simple life table model was constructed for Tetranychus urticae in which daily survivorship of eggs and motil stages, fecundity, and development time was altered to assess the impact of each parameter on the intrinsic rate of increase. r. Interpretation of the trade-offs focused on management considerations. A second aspect of the study concerned age and stage structure in mite populations including the time path of convergence to a stable age distribution and the effect of changes in birth and death rates on the age profile. The stable stage distributions of 7 tetranychid mite species were computed using 25 separate life tables. In spite of the wide range of r-values induced by different experimental conditions, all of the stage distributions were quite similar averaging roughly 66% eggs, 26% immatures, and 8% adults. Several population studies were cited which reported stage distributions of growing mite populations. The empirical evidence suggested that natural mite populations are often quite near this stable distribution. A practical problem involving the extent to which hormoligosis (insecticide stimulation) affects mite population growth rate was addressed using the life table model and laboratory data from controlled studies. The findings suggested that mite populations treated with insecticide may attain a 1.4- to a 4.2-fold difference in population size relative to an untreated population after 2 generations and over a 1,300-fold potential difference after 10 generations.
    Type of Medium: Electronic Resource
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