Nutritional Stress Causes Heterogeneous Relationships with Multi-Trait FA in Lesser Black-Backed Gull Chicks: An Aviary Experiment

• Published in: Symmetry
• Main Authors: Trisha Gupta, Cátia S. A. Santos, Alejandro Sotillo, Liesbeth De Neve, Eric W. M. Stienen, Wendt Müller, Luc Lens
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2016
• Subjects: fluctuating asymmetry; Larus fuscus; nutritional stress; energetic constraints; biomarkers; Mathematics; QA1-939; Lesser black-backed gull
• Online Access: https://doi.org/10.3390/sym8110133; https://doaj.org/article/9692dda6f419451691a744de0a700f92

Environmental stressors have the potential to induce perturbations in the development of young individuals, leading to aberrant and unstable development. This may manifest as fluctuating asymmetry (FA; small, non-directional changes in the bilateral symmetry of morphological traits). Although widely regarded as a proxy for stress effects, the use of FA as a biomarker is still a topic of much debate. We investigated the applicability of FA as an indicator of nutritional stress (brought about by energetic constraints) by experimental manipulation of the diet composition and quantity during the growth of Lesser Black-backed Gull (Larus fuscus) chicks. FA as an endpoint was measured across the tarsus, wing and 10th primary feather when chicks reached 30 days of age. Although levels of asymmetry were found to increase with stress in the feather, relationships with tarsus and wing FA were mixed and mostly non-significant. Furthermore, we did not find any correlations in unsigned FA between traits, indicating the absence of organism-wide asymmetry. Our study was therefore unable to find unequivocal evidence in support of the application of FA as a reliable estimator of nutritional stress.