Insulin-like growth factor-1 is associated with life-history variation across Mammalia.
Despite the diversity of mammalian life histories, persistent patterns of covariation have been identified, such as the 'fast-slow' axis of life-history covariation. Smaller species generally exhibit 'faster' life histories, developing and reproducing rapidly, but dying young. Hormonal mechanisms with pleiotropic effects may mediate such broad patterns of life-history variation. Insulin-like growth factor 1 (IGF-1) is one such mechanism because heightened IGF-1 activity is related to traits associated with faster life histories, such as increased growth and reproduction, but decreased lifespan. Using comparative methods, we show that among 41 mammalian species, increased plasma IGF-1 concentrations are associated with fast life histories and altricial reproductive patterns. Interspecific path analyses show that the effects of IGF-1 on these broad patterns of life-history variation are through its direct effects on some individual life-history traits (adult body size, growth rate, basal metabolic rate) and through its indirect effects on the remaining life-history traits. Our results suggest that the role of IGF-1 as a mechanism mediating life-history variation is conserved over the evolutionary time period defining mammalian diversification, that hormone-trait linkages can evolve as a unit, and that suites of life-history traits could be adjusted in response to selection through changes in plasma IGF-1.
['Swanson|Eli M|EM|', 'Dantzer|Ben|B|']
D000818:Animals D001481:Basal Metabolism D005075:Biological Evolution D049628:Body Size D007334:Insulin-Like Growth Factor I D008018:Life Cycle Stages D008322:Mammals D010641:Phenotype D010802:Phylogeny D012098:Reproduction
insulin-like growth factor-1 life history comparative analysis fast–slow axis mammals