Researches on Population Ecology

, Volume 34, Issue 1, pp 29-44

First online:

Marginal attack rate,k-values and density dependence in the analysis of contemporaneous mortality factors

  • J. S. ElkintonAffiliated withDepartment of Entomology, University of Massachusetts
  • , J. P. BuonaccorsiAffiliated withDepartment of Mathematics and Statistics, University of Massachusetts
  • , T. S. BellowsJr.Affiliated withDepartment of Entomology, University of California
  • , R. G. Van DriescheAffiliated withDepartment of Entomology, University of Massachusetts

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  1. 1.

    Procedures for calculating the marginal attack rates and associatedk-values from observed death rates are presented for contemporaneous predators or parasitoids that either do or do not discriminate against previously parasitized hosts.

  2. 2.

    The relationships among previous methods for quantifying contemporaneous mortalities are discussed.

  3. 3.

    Solutions to the problem of calculating marginal rates taken from human survival analysis are given under the assumption of proportional hazards. These calculations are easily extended to three or more contemporaneous sources of mortality.

  4. 4.

    The conditions under which proportional hazards can be expected are discussed.

  5. 5.

    These methods are compared to that of Varley et al., 1973 for assessment of density dependence among contemporaneous predators.



marginal rate apparent mortality survival analysis hazard rate life tables predation