Meeting Abstract
As a pace-setter for physiological processes, variation in metabolic rate can determine the shape of energetic trade-offs and thereby be an important factor that facilitates variation in life-history traits. In turn, such variation in metabolic performance and life-histories can have profound consequences for fitness. Thus, the extent to which metabolic variation is due to phenotypic plasticity or fixed genetic differences among individuals or populations is likely to be shaped by natural selection. We synthesize our studies on metabolic rate variation in garter snakes (Thamnophis elegans) exhibiting contrasting life-history strategies – either growing fast and reproducing early versus growing slowly and delaying maturation – that have been measured in a variety of age classes and developmental backgrounds. With this synthesis of numerous datasets, we are able to ascertain the relative influences of developmental plasticity and local adaptation in shaping thermal reaction norms of metabolic rate. Furthermore, we provide new data on the association of fixed metabolic differences with mitochondrial haplotype divergences between the ecotypes. Finally, we assess the fitness consequences of this interrelated metabolic rate variation and life-history variation for these snakes.
