Metabolism, personality and pace of life in the Trinidadian guppy, Poecilia reticulata

While among-individual variation in behaviour, or personality, is common across taxa, its mechanistic underpinnings are poorly understood. The Pace of Life syndrome (POLS) provides one possible explanation for maintenance of personality differences. POLS predicts that metabolic differences will covary with behavioural variation, with high metabolism associated with risk prone behaviour and 'faster' life histories (e.g., high growth, early maturation). We used a repeated measures approach, assaying metabolic traits (rate and scope), behaviour and growth to test these predictions in the Trinidadian guppy, Poecilia reticulata. We found that while individuals varied significantly in their behaviour and growth rate, more risk prone individuals did not grow significantly faster. Furthermore, after accounting for body size there was no support for among-individual variation in metabolic traits. Thus, while personality differences are clearly present in this population, they do not covary with metabolism and the POLS framework is not supported.