Unexpected discontinuities in life-history evolution under size-dependent mortality

Taborsky B, Dieckmann U, & Heino M (2003). Unexpected discontinuities in life-history evolution under size-dependent mortality. Proceedings of the Royal Society B: Biological Sciences 270 (1516): 713-721. DOI:10.1098/rspb.2002.2255.

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Abstract

In many organisms survival depends on body size. We investigate the implications of size-selective mortality on life-history evolution by introducing and analysing a new and particularly flexible life-history model with the following key features: the lengths of growth and reproductive periods in successive reproductive cycles can vary evolutionarily, the model does not constrain evolution to patterns of either determinate or indeterminate growth, and lifetime number and sizes of broods are the outcomes of evolutionarily optimal life-history decisions. We find that small changes in environmental conditions can lead to abrupt transitions in optimal life histories when size-dependent mortality is sufficiently strong. Such discontinuous switching results from antagonistic selection pressures and occurs between strategies of early maturation with short reproductive periods and late maturation with long reproductive cycles. When mortality is size-selective and the size-independent component is not too high, selection favours prolonged juvenile growth, thereby allowing individuals to reach a mortality refuge at large body size before the onset of reproduction. When either component of mortality is then increased, the mortality refuge first becomes unattractive and eventually closes up altogether, resulting in short juvenile growth and frequent reproduction. Our results suggest a new mechanism for the evolution of life-history dimorphisms.

Item Type: Article
Uncontrolled Keywords: Life-history model; Size-dependent mortality; Growth; Time allocation; State-dependent decisions; Bifurcation
Research Programs: Adaptive Dynamics Network (ADN)
Bibliographic Reference: Proceedings of the Royal Society B: Biological Sciences; 270(1516):713-721 (7 April 2003)
Depositing User: IIASA Import
Date Deposited: 15 Jan 2016 02:15
Last Modified: 23 Aug 2016 09:37
URI: http://pure.iiasa.ac.at/6888

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