Disruptive viability selection on a black plumage trait associated with dominance

Area of Science:

• Evolutionary biology
• Animal communication
• Behavioral ecology

Background:

• Communication signals are linked to reproduction, but survival associations are less understood.
• Melanin-based traits' costs and survival impacts, particularly in dominance signaling, require further investigation.

Purpose of the Study:

• To investigate factors influencing bib size variation in sociable weavers.
• To analyze the relationship between bib size and survival using capture-recapture models.
• To identify patterns of viability selection on a melanin-based signal.

Main Methods:

• Determined factors affecting bib size variability (year, age, condition, colony size).
• Calculated individual mean bib size expression.
• Applied capture-recapture models to assess survival in relation to bib size.

Main Results:

• Bib size varied significantly with year, age, body condition, and colony size.
• A U-shaped relationship was observed between bib size and survival.
• Individuals with extreme bib sizes (small or large) exhibited higher survival than those with intermediate bibs.

Conclusions:

• Disruptive viability selection acts on bib size in sociable weavers.
• Social costs associated with dominance signaling may influence survival.
• The plasticity of signals and environmental factors can modulate selection pressures.