Effects of brood size manipulation and common origin on phenotype and telomere length in nestling collared flycatchers
1 Department of Ecology and Evolution, Biophore, University of Lausanne, CH-1015, Lausanne, Switzerland
2 Département d’Ecologie, Physiologie et Ethologie, CNRS, Université de Strasbourg, IPHC, F-67087 Cedex 2, Strasbourg, France
3 Department of Animal Ecology, Evolutionary Biology Centre, Uppsala University, SE-752 36, Uppsala, Sweden
4 Department of Biometry and Evolutionary Biology, CNRS, Université de Lyon, Lyon; Université Lyon 1, F-69000, LBBE UMR 5558, Bâtiment Gregor Mendel, 43 boulevard du 11 november 1918, F-69622, Villeurbanne, France
BMC Ecology 2012, 12:17 doi:10.1186/1472-6785-12-17Published: 18 August 2012
Evidence is accumulating that telomere length is a good predictor of life expectancy, especially early in life, thus calling for determining the factors that affect telomere length at this stage. Here, we investigated the relative influence of early growth conditions and origin (genetics and early maternal effects) on telomere length of collared flycatchers (Ficedula albicollis) at fledging. We experimentally transferred hatchlings among brood triplets to create reduced, control (i.e. unchanged final nestling number) and enlarged broods.
Although our treatment significantly affected body mass at fledging, we found no evidence that increased sibling competition affected nestling tarsus length and telomere length. However, mixed models showed that brood triplets explained a significant part of the variance in body mass (18%) and telomere length (19%), but not tarsus length (13%), emphasizing that unmanipulated early environmental factors influenced telomere length. These models also revealed low, but significant, heritability of telomere length (h2 = 0.09). For comparison, the heritability of nestling body mass and tarsus length was 0.36 and 0.39, respectively, which was in the range of previously published estimates for those two traits in this species.
Those findings in a wild bird population demonstrate that telomere length at the end of the growth period is weakly, but significantly, determined by genetic and/or maternal factors taking place before hatching. However, we found no evidence that the brood size manipulation experiment, and by extension the early growth conditions, influenced nestling telomere length. The weak heritability of telomere length suggests a close association with fitness in natural populations.