Search Results - (Author, Cooperation:S. Boutin)

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  1. 1
  2. 2
    B. Dantzer ; A. E. Newman ; R. Boonstra ; R. Palme ; S. Boutin ; M. M. Humphries ; A. G. McAdam
    American Association for the Advancement of Science (AAAS)
    Published 2013
    Staff View
    Publication Date:
    2013-04-20
    Publisher:
    American Association for the Advancement of Science (AAAS)
    Print ISSN:
    0036-8075
    Electronic ISSN:
    1095-9203
    Topics:
    Biology
    Chemistry and Pharmacology
    Computer Science
    Medicine
    Natural Sciences in General
    Physics
    Keywords:
    *Adaptation, Physiological ; Animals ; Cues ; Female ; Glucocorticoids/*metabolism ; *Growth and Development ; Hydrocortisone/blood ; Litter Size/*physiology ; Maternal Behavior/*physiology ; Population Density ; Sciuridae/*physiology ; Selection, Genetic ; Vocalization, Animal
    Published by:
    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Caley, J. ; Boutin, S.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0003-3472
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  4. 4
    Caley, J. ; Boutin, S.

    Amsterdam : Elsevier
    Staff View
    ISSN:
    0003-3472
    Source:
    Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics:
    Biology
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  5. 5
    Caley, M. J. ; Boutin, S. ; Moses, R. A.
    Springer
    Published 1988
    Staff View
    ISSN:
    1432-1939
    Keywords:
    Local resource competition ; Muskrat ; Parental investment ; Rodent ; Sex-ratio adjustment
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Notes:
    Summary Sex ratios of a population and of litters were sampled in muskrats in Ontario, Canada. Sex ratios of litters sampled from nests were male biased (54% male). Until weaning, no differential costs of producing and rearing male and female young were identified that could account for this greater production of males. Following weaning, however, male-biased dispersal of juveniles from their natal site and more frequent acquisition by females of these sites as breeding sites the following year suggested a greater investment by adult females in female young. Therefore, competition between female siblings for the acquisition of their natal site may be sufficient to result in the greater production of males. In addition, the simultaneous occupation of, and competition between, siblings and parents for the resources of the natal home range may not be necessary for local resource competition to result in a greater production of the dispersing sex. Greater-than-expected binomial variance in sex ratios of litters suggested that adjustment of sex-ratios occurred. However, we were unable to associate the adjustment of litter sex ratios with changes in maternal condition. The greater production of males and the predominance of monogamous associations between adults in this population may have lead to slightly greater variation in male fitness than female fitness. Therefore, a female in better-than-average condition may have benefited by producing more males. Similarly, a lower cost of producing dispersing males may allow nutritionally-stressed females to reduce their total expenditure on offspring by producing more males. Because these experiments were non-manipulative, maternal condition may not have varied sufficiently during this study to detect adjustments of litter sex ratios resulting from either of the above mechanisms acting separately, but the combined effects of small differences in matermal condition and selective pressures operating in the same direction may have resulted in the observed deviation from the binomial.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  6. 6
    Staff View
    ISSN:
    1432-1939
    Keywords:
    Competition ; Regulation ; Ungulates ; Disease ; Serengeti
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Biology
    Notes:
    Summary Changes in populations of several ungulate species in the Serengeti-Mara region of East Africa over the past 30 years suggest several hypotheses for their regulation and coexistence. Recent censuses in the 1980s have allowed us to test the hypotheses that: (1) there was competition between wildebeest (Connochaetes taurinus) and Thomson's gazelle (Gazella thomsoni). This predicted that gazelle numbers should have declined in the 1980s when wildebeest were food limited. Census figures show no change in gazelle numbers between 1978 and 1986, a result contrary to the interspecific competition hypothesis; (2) wildebeest and African buffalo (Syncerus caffer) populations were regulated by intraspecific competition for food. Since both populations reached food limitation in the 1970s, the hypothesis predicted that the populations should have been stable in the 1980s. The results confirm these predictions for wildebeest and the buffalo population in the Mara reserve. In the Serengeti the buffalo population declined 41% over the period 1976–1984. The decline was not evenly distributed over the park, some areas showing an 80–90% decline, others no change or an increase in numbers. The decline was associated with proximity to human habitation; (3) an outbreak of the viral disease, rinderpest, in 1982 may have been the cause of the drop in buffalo population. Blood serum samples to measure the prevalence of antibodies were collected from areas of decreasing, stable and increasing populations. If rinderpest was the cause of decrease there should be a negative relationship between the prevalence of rinderpest and the instantaneous rate of increase (r). The results showed no relationship. We conclude that rinderpest was not the major cause of the drop in buffalo numbers. Elephant (Loxodonta africana) numbers dropped 81% in Serengeti in the period 1977–1986. In the Mara there was little change. The evidence suggests that extensive poaching in northern and western Serengeti during 1979–1984 accounted for the drop in both elephant and buffalo numbers.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses