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Experimental Manipulation of Body Size to Estimate Morphological Scaling Relationships in Drosophila
Published on: October 1, 2011
Unexpected discontinuities in life-history evolution under size-dependent mortality
Barbara Taborsky1, Ulf Dieckmann, Mikko Heino
1Department of Behavioural Ecology, University of Bern, Wohlenstrasse 50A, CH-3032 Hinterkappelen, Switzerland. barbara.taborsky@esh.unibe.ch
Proceedings. Biological Sciences
|April 26, 2003
Summary
Life-history evolution is impacted by size-selective mortality. Optimal strategies shift abruptly between early and late maturation due to environmental changes and strong size-dependent mortality.
Area of Science:
- Evolutionary biology
- Ecology
- Life-history theory
Background:
- Organism survival is often contingent on body size.
- Size-selective mortality is a key factor influencing evolutionary trajectories.
- Existing life-history models often impose constraints on growth patterns.
Purpose of the Study:
- To investigate the evolutionary implications of size-selective mortality on life-history strategies.
- To analyze a flexible life-history model allowing variable growth and reproductive periods.
- To explore the conditions leading to abrupt shifts in optimal life-history decisions.
Main Methods:
- Development of a novel, flexible life-history model.
- Analysis of evolutionary optimal life-history decisions under varying mortality regimes.
- Examination of size-dependent and size-independent mortality components.
- Modeling of determinate and indeterminate growth patterns.
Main Results:
- Small environmental changes can trigger abrupt transitions in optimal life histories under strong size-dependent mortality.
- Discontinuous switching occurs between early maturation/short reproduction and late maturation/long cycles.
- Prolonged juvenile growth is favored to reach a mortality refuge at larger body sizes.
- Increased mortality components lead to shorter juvenile growth and more frequent reproduction.
Conclusions:
- Size-selective mortality can drive rapid evolutionary shifts in life-history strategies.
- A 'mortality refuge' mechanism explains prolonged juvenile growth.
- This study proposes a new mechanism for the evolution of life-history dimorphisms.
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