Metabolic rate is a widely-studied physiological species trait related to energetics, climate, and geographic distributions. Hypotheses have been proposed to explain variation in metabolic rate, but evidence has been mixed due to the limited sampling scope of intraspecific studies. Successful biological invasions offer a unique opportunity to examine the development of intraspecific physiological variation and how it relates to climate, invasive spread, and species range limits. Here we conducted a macro-scale study of routine metabolic rate variation across the Spongy moth (Lymantria dispar) invasive range in North America. We found a positive latitudinal cline with population-specific metabolic rates increasing from the southern range to the north that was significantly related to climate. Our comprehensive macrophysiological analyses provide further evidence that local adaptation of physiological and life history traits to climate has played a significant role in the spread of L. dipsar across the landscape in the past 150 years.