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Modèle d’étude des effets de la pluviométrie, de la prédation et de la quiescence des œufs sur la dynamique des populations du |
Science et changements planétaires / Sécheresse. Volume 7, Number 2, 145-50, Juin 1996, Méthodologie
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 Résumé
 Summary
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Author(s) : John Colvin, Johnson Holt, Naturel Resources Institute, Central Avenue, Chatham Maritime, Chatham, Kent ME4 4TB, Royaume-Uni. |
Summary : A population model was developed to investigate the interactions between
Oedaleus senegalensis (Krauss), its bombyliid egg predators and rainfall. Under conditions of good rains alternating with drought, the
O. senegalensis population oscillates with rainfall, whereas the predators slowly die out. With continuously good rains, the situation is quite different and the predators are able to persist in large numbers and play a major role in determining the size of the grasshopper population. The level of
O. senegalensis egg quiescence does not affect the general principle that drought severity reduces predator efficacy. A larger egg-pod bank, however, does improve predator survival during periods of drought, thereby allowing the predators to build up and stem the
O. senegalensis outbreak if the good conditions last long enough. Even if very efficient, however, the predators take time to catch up with the
O. senegalensis population and consequently, outbreaks inevitably occur after periods of drought. The relevance of these findings to
O. senegalensis outbreak forecasting is discussed. |
ARTICLE
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