Advertisement

Population Ecology

, Volume 44, Issue 3, pp 0265–0272 | Cite as

Indeterminate growth is selected by a trade-off between high fecundity and risk avoidance in stochastic environments

  • Y. Katsukawa
  • T. Katsukawa
  • H. Matsuda
ORIGINAL ARTICLE

Abstract

 We developed a stage-structured model to describe optimal energy allocation among growth, reproduction, and survival. Our model includes stochastic fluctuations in survival rate at age 0 but constant survival rate at older ages. Many mammals and birds cease to grow after maturity (i.e., determinate growth), whereas organisms in a number of other taxa grow beyond maturation (i.e., indeterminate growth). We discuss the conditions under which each of the following strategies is optimal: (I) semelparity, (II) iteroparity with determinate growth, and (III) iteroparity with indeterminate growth. Our model demonstrates that iteroparity with indeterminate growth is selected for when a nonlinear relationship exists between weight and energy production; this strategy is also often selected for in stochastic environments, even with a linear relationship between weight and energy production. The optimal strategy in stochastic environments is to maximize the long-term population growth rate, which does not correspond with maximization of total fecundity. The optimal life history is determined by a balance between spreading a risk and increasing the number of offspring. Our model suggests that optimal life history strategy depends on the magnitude of environmental fluctuations, the advantage of investing in growth, the cost of survival, and the nonlinearity between weight and energy production.

Key words Energy allocation Stochastic growth rate Stage-structured matrix model Semelparity Iteroparity 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© The Society of Population Ecology and Springer-Verlag Tokyo 2002

Authors and Affiliations

  • Y. Katsukawa
    • 1
  • T. Katsukawa
    • 1
  • H. Matsuda
    • 1
  1. 1.Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano-ku, Tokyo 164-8639, Japan Tel. +81-3-5351-6495; Fax +81-3-5351-6492 e-mail: yu@ori.u-tokyo.ac.jpJP

Personalised recommendations