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Handicap signalling: when fecundity and viability do not add up
1Kellogg Biological Station and Department of Zoology, Michigan State University
Animal Behaviour
|December 16, 1998
Summary
Honest handicap signalling requires higher fitness benefits for high-quality signallers, not just lower costs. This challenges the traditional view and emphasizes the role of fitness trade-offs in honest signalling.
Area of Science:
- Evolutionary biology
- Animal behaviour
- Game theory
Background:
- The traditional handicap principle posits that honest signalling relies on higher costs for low-quality individuals.
- Life history models often predict non-additive fitness effects, challenging this assumption.
Purpose of the Study:
- To generalize the criterion for honest handicap signalling.
- To explore the role of fitness benefits versus costs in signalling.
- To provide a framework for experimental testing of the handicap hypothesis.
Main Methods:
- Theoretical analysis of fitness effects in signalling.
- Exploration of fitness surfaces for correlated characters (quality and advertising).
- Review of existing experimental designs and their limitations.
Main Results:
- The general criterion for honest signalling is higher marginal fitness effects for high-quality signallers.
- This can be achieved through higher benefits, not solely lower costs.
- A 'fitness ridge' on the quality-advertising surface is implied, requiring specific cost-benefit trade-offs.
Conclusions:
- Honest handicap signalling is better explained by differential fitness gains than differential costs.
- Experimental tests should focus on identifying rising fitness ridges driven by cost-benefit trade-offs.
- Receiver behaviour, including sensory bias, can influence signal exaggeration without violating the core handicap principle.