INVESTIGADORES
PALACIOS Maria Gabriela
artículos
Título:
Evolutionary ecology of senescence: a case study using Tree Swallows, Tachycineta bicolor.
Autor/es:
VLECK, C. M.; VLECK, D.; PALACIOS, M. G.
Revista:
Journal of Ornithology
Editorial:
Springer
Referencias:
Año: 2011 vol. 152 p. 203 - 211
ISSN:
1439-0361
Resumen:
Tree swallows, Tachycineta bicolor, have been studied at nest box colonies at sites throughout North America. They can be easily aged, captured, repeatedly sampled and their physiology and reproductive success measured across their lifetime. These traits make tree swallows an important model species for many ecological and evolutionary studies. We have studied aging in free-living tree swallows colonies located in Iowa and New York, USA for several years. Telomeres, the DNA “caps” on each chromosome, shorten with age, which may contribute to the aging phenotype, and birds with longer telomeres at one year of age have a significantly longer predicted life span than birds with shorter telomeres. Tree swallows display decreased cell-mediated immune function with age, but other components of the immune system do not decline with age. Older, nesting females who display immunosenescence also show exaggerated sickness behavior in response to lipopolysaccharide injections, which suggests that immunosenescence carries fitness costs in the wild. Preliminary data from metabolically-handicapped tree swallows suggests birds suffer lower reproductive success, increased telomere shortening, increased oxidative damage and reduced immune function. Continued cross-sectional and longitudinal tracking of tree swallows will contribute to understanding the evolutionary ecology of senescence.