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The evolution of avian parental care
Nancy Tyler Burley1, Kristine Johnson
1Department of Ecology and Evolutionary Biology, University of California, Irvine 92697-2525, USA. ntburley@uci.edu
Summary
This study outlines a four-stage model for the evolution of social monogamy with biparental care from promiscuity. Key behavioral tactics and life-history traits drove this transition in mating systems.
Area of Science:
- Evolutionary biology
- Behavioral ecology
- Zoology
Background:
- Reptiles typically exhibit promiscuity with no parental care.
- Most birds display social monogamy with biparental care.
- The evolutionary transition between these mating systems is not fully understood.
Purpose of the Study:
- To propose a stage model detailing the behavioral tactics and life-history traits involved in the evolution of social monogamy with biparental care.
- To elucidate the mechanisms driving the shift from promiscuity to monogamy.
Main Methods:
- A theoretical stage model approach was used.
- Key behavioral tactics and life-history traits were traced through four distinct stages.
- Hypotheses for testing the proposed model were suggested.
Main Results:
- Stage I: Increased female parental investment, mate choice, female-biased dispersal, and male-biased sex ratios.
- Stage II: Consortships facilitated mate attraction, paternity assessment, and female assessment of mate quality.
- Stage III: Female scarcity led to demands for male parental investment with paternity certainty.
- Stage IV: Altriciality coevolved with biparental care, establishing social monogamy.
Conclusions:
- The proposed stage model provides a framework for understanding the evolution of social monogamy and biparental care.
- Behavioral tactics and life-history shifts, including changes in parental investment and mate assessment, were crucial.
- The model highlights the gradual development of complex care systems from simpler mating strategies.