Density dependence in cereal aphid populations |
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Authors: | M J. MAUDSLEY A. MACKENZIE J I. THACKER A F G. DIXON |
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Affiliation: | School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK |
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Abstract: | Long sequences of data on the incidence of cereal aphids from five European countries were analysed for evidence of density dependent processes occurring between years. Using a randomisation test (Pollard, Lakhani & Rotheray, 1987), density dependence was revealed in all (16) population censuses of Metopolo-phium dirhodum , 60% of Rhopalosiphum padi censuses (10 of 17) but only 25% of Sitobion avenae population censuses (4 of 16). Correcting for density independent effects of weather revealed the existence of significant direct density dependence in some populations censuses where it was previously undetected. The implications of density dependence in cereal aphid populations are considered. |
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Keywords: | Cereal aphids Metopolophium dirhodum Rhopalosiphum padi Sitobion avenae density dependence population dynamics weather |
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