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AN APPRAISAL OF TWO METHODS OF ANALYZING INSECT LIFE TABLES1

Published online by Cambridge University Press:  31 May 2012

Robert F. Luck
Robert F. Luck
Affiliation:
Division of Biological Control, University of California, Berkeley
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Abstract

Two methods of analyses, Morris’ key-factor analysis and Varley and Gradwell’s method of analysis, purport to detect density-dependent and density-independent mortality. To test their claims, both methods were used to analyze a life table constructed from a model in which the mode of action of each mortality factor is known. The results show that Morris’ method can detect variation in mortality between generations but it cannot distinguish the density relationships of that mortality. On the other hand, Varley and Gradwell’s method of analysis was found to detect the density relationships of the mortality as it was modeled, when their modified method, the ’proof of density dependence test,’ is used in conjunction with the linear regression of k-value against the density on which it acts.

Type
Articles
Information
The Canadian Entomologist , Volume 103 , Issue 9 , September 1971 , pp. 1261 - 1271
Copyright
Copyright © Entomological Society of Canada 1971

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