Brood size moderates associations between relative size, telomere length, and immune development in European starling nestlings



Nettle D, Andrews C, Reichert S, Bedford T, Gott A, Parker C, Kolenda C, Martin-Ruiz C, Monaghan P & Bateson M (2016) Brood size moderates associations between relative size, telomere length, and immune development in European starling nestlings. Ecology and Evolution, 6 (22), pp. 8138-8148.

For young birds in a nest, body size may have implications for other aspects of development such as telomere length and immune function. However, it is possible to predict associations in either direction. On the one hand, there may be trade-offs between growth and telomere maintenance, and growth and investment in immune function, suggesting there will be negative correlations. On the other hand, relatively larger individuals might be advantaged in competition with their nest-mates, allowing them to garner more resources overall, leading to positive correlations. We studied development over the nestling period in 34 nests of wild European starlings, Sturnus vulgaris. Intrabrood competition is typically more intense in larger broods. Hence, we predicted that body size should become an increasingly positive predictor of telomere length and immune functioning as brood size increases. In partial support of our prediction, there were significant interactions between brood size and body size in predicting both erythrocyte telomere length change and plasma levels of the cytokine interleukin-6. The associations between body size and these outcomes went from negative in the smallest broods to positive in the largest. A further immune marker, high-sensitivity C-reactive protein, showed no systematic patterning with body size or brood size. Our results confirm that the size to which a nestling grows is important for telomere dynamics and the development of the immune system, but the phenotypic associations are moderated by the competitive context.

body size; ecological immunology; growth; Sturnus vulgaris; starlings; telomeres

Ecology and Evolution: Volume 6, Issue 22

FundersBiotechnology and Biological Sciences Research Council, Biotechnology and Biological Sciences Research Council, European Research Council and European Research Council
Publication date30/11/2016
Publication date online17/10/2016
Date accepted by journal20/09/2016

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Dr Clare Andrews

Dr Clare Andrews

Lecturer in Psychology, Psychology