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The peacock train does not handicap cursorial locomotor performance
Nathan K Thavarajah1, Peter G Tickle2, Robert L Nudds1
1The Faculty of Biology, Medicine and Health, University of Manchester, Manchester, M13 9PT, UK.
Scientific Reports
|November 3, 2016
Summary
Peacocks with exaggerated sexual traits, like their trains, do not have impaired movement. Surprisingly, these trains lower the metabolic cost of locomotion, suggesting adaptations mitigate trait-related expenses.
Area of Science:
- Evolutionary Biology
- Animal Behavior
- Physiology
Background:
- Sexual selection drives the evolution of exaggerated traits, such as peacock trains.
- These traits are paradoxically thought to hinder survival and locomotion due to increased mechanical load.
- The impact of exaggerated traits on metabolic cost and locomotor performance remains debated.
Purpose of the Study:
- To investigate the effect of the peacock's exaggerated train on the metabolic cost and kinematics of locomotion.
- To determine if sexually selected traits impose a significant energetic penalty on movement.
Main Methods:
- Respirometry experiments were conducted on peacocks to measure oxygen consumption during locomotion.
- Locomotor performance was assessed by analyzing the metabolic cost and kinematic parameters.
- Peacocks with varying train sizes were included in the study.
Main Results:
- The exaggerated peacock train did not compromise locomotor performance.
- Peacocks with trains exhibited a lower absolute and mass-specific metabolic cost of locomotion.
- This suggests efficient energy utilization despite the ornate appendage.
Conclusions:
- Exaggerated sexually selected traits, like the peacock train, do not necessarily impair locomotor performance.
- Adaptations that mitigate the energetic costs associated with exaggerated morphology are crucial for trait evolution.
- The study challenges the assumption that costly sexual traits are always a survival disadvantage.
