AO_SCPLOWBSTRACTC_SCPLOWMetabolic rate is often measured as a phenotype in evolutionary genetics studies because it impacts organismal fitness, is repeatable and heritable, and is responsive to numerous environmental variables. Despite a wide body of literature about metabolic rates, key questions remain unanswered: 1) why do individuals from the same population exhibit up to three fold differences in metabolic rate, 2) how does metabolic rate change during an individuals lifetime, and 3) what metabolic rate is advantageous in a specific environment? Current low throughput approaches to measure metabolic rate make it difficult to answer these and other relevant ecological and evolutionary questions that require a much larger sample size. Here we describe a scalable high-throughput intermittent flow respirometer (HIFR) design and use it to measure the metabolic rates of 20 aquatic animals simultaneously while reducing equipment costs and time by more than 50%.
