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Female Starlings With Experimentally Impaired Pre-Laying Condition Produce Smaller But Vitamin A Richer Eggs
S Casquero1,2, I Redondo2, E Gómez-Llanos2
1Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCCM, Ciudad Real, Spain.
Summary
Female birds in poor condition lay smaller eggs but strategically increase vitamin A. This maternal effect impacts offspring viability despite reduced egg size, showing adaptive resource allocation.
Area of Science:
- Reproductive biology
- Maternal effects in oviparous species
- Animal physiology
Background:
- Egg production is a key reproductive investment for females.
- Egg number, size, and yolk composition influence offspring viability.
- Yolk components like antioxidants and hormones shape offspring development.
Purpose of the Study:
- To investigate how female body condition affects egg characteristics and yolk composition.
- To understand maternal effects on offspring fitness via egg investment.
Main Methods:
- Experimentally impaired body condition in wild spotless starlings (Sturnus unicolor) by feather clipping.
- Assessed clutch size, egg size, and yolk composition (androgens, antioxidants, oxidative damage).
Main Results:
- Impaired condition led to smaller egg size but not reduced clutch size.
- Yolk concentrations of androgens, carotenoids, and vitamin E were not significantly affected.
- Eggs from impaired females showed higher vitamin A and a trend towards increased lipid oxidation.
Conclusions:
- Females adjust egg characteristics and yolk components based on their body condition.
- Poor condition may trigger strategic increases in yolk vitamin A to potentially compensate for smaller egg size.
