Fecundity selection theory: concepts and evidence.

Area of Science:

• Evolutionary Biology
• Ecology
• Life History Theory

Background:

• Fitness is a balance of survival, mating, and fecundity.
• Fecundity selection is less studied than natural (survival) and sexual (mating) selection.
• Understanding fecundity selection is crucial for ecological and evolutionary dynamics.

Purpose of the Study:

• Review the theory, evidence, and implications of fecundity selection.
• Propose a conceptual re-arrangement of fecundity concepts.
• Examine fecundity selection's role in sex-specific adaptive evolution.

Main Methods:

• Literature review of life-history, phenotypic, and ecological aspects of fecundity.
• Conceptual analysis of fecundity selection theory.
• Synthesis of existing evidence and theoretical frameworks.

Main Results:

• Introduced 'transient fecundity' for brood size per episode.
• Redefined fecundity selection to include traits influencing fecundity in either sex.
• Questioned the female-biased sexual size dimorphism hypothesis driven by fecundity selection.
• Highlighted the need for studies beyond birds and on male fecundity selection.

Conclusions:

• Clarifying fecundity concepts is essential for understanding adaptive evolution.
• Fecundity selection is a significant, yet underappreciated, evolutionary force.
• Further research is needed on fecundity selection across diverse taxa and sexes.