Phenotypic plasticity in body growth enables organisms to cope with unpredictable paucities in resource availability. Growth traits influence survival and reproductive success, and thereby, population persistence, and early-life resource availability may govern lifetime patterns in growth, reproductive success, and survival. The influence of early-life environment is decidedly consequential for indeterminately growing ectotherms, which rely on available resources and ambient temperatures to maximize fitness throughout life. Using 17 years of mark-recapture data, we evaluate the effects of resource availability on patterns in growth for populations of western terrestrial garter snakes (Thamnophis elegans), which differ along pace-of-life continuums into fast- and slow-living ecotypes. We use an adaptation of the von Bertalanffy estimator to fit structural growth models and linear predictors for body condition to analyze the consequences of annual and early-life prey availability. Snakes from resource-poor early-life environments are primed to exploit conditions in high-prey environments later in life. Slow pace-of-live animals exhibit a greater capacity for compensatory strategies in structural growth, while body condition was best explained by a complex interaction across males and non-gravid females between prey availability and ecotype. Our findings highlight the importance of accounting for context-dependent early-life environments as well as sex-specific reproductive demands when evaluating population traits.
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