Fruit resources shape sexual selection processes in a lek mating system.

Area of Science:

• Behavioral Ecology
• Evolutionary Biology
• Ornithology

Background:

• Sexual trait variation in lek-mating species is often attributed to genetic factors.
• The role of environmental resource heterogeneity in shaping male mating success is understudied in these systems.

Purpose of the Study:

• To investigate the relationship between fine-scale fruit resource availability and male mating success in the white-bearded manakin (Manacus manacus).
• To determine if local resource availability influences the energetically costly courtship displays of male manakins and subsequent female visitation.

Main Methods:

• Utilized motion-activated camera traps to monitor male display behavior and female visitation rates at display courts.
• Conducted twice-monthly fruit surveys to quantify ripe fruit biomass around male display courts.
• Employed causal modeling to analyze the indirect effects of fruit availability on female visitation through male display rates.

Main Results:

• Significant variation in ripe fruit biomass was observed among display courts and leks.
• Mean fruit biomass at courts positively predicted male display rates.
• Male display rate was the strongest predictor of female visitation, with causal modeling supporting an indirect effect of fruit availability.

Conclusions:

• Local fruit availability significantly influences male display rates and, consequently, female visitation in lekking white-bearded manakins.
• This demonstrates that ecological resource availability can play a crucial role in the expression and maintenance of sexually selected traits, even in species where genetic factors are presumed dominant.
• Findings have implications for understanding sexual selection under fluctuating environmental conditions.