Commentary: The ecological and evolutionary implications of allometry

Allometry—the study of proportional growth of body parts, and the relationship of body size to an organism’s morphology, physiology and behaviour—is a fundamental influencer of ecological and evolutionary diversity. Allometric studies can focus on scaling across an individual's development (ontogenetic allometry), among individuals at the same developmental stage (static allometry), and among species (evolutionary allometry). The key assumption in allometry is that an organism’s body size is a critical factor in shaping its biology, so biological scaling underpins biological diversity. This commentary accompanies a special issue that collates original research papers on the wide-ranging ecological and evolutionary implications of biological scaling. We discuss the common themes uniting each contribution, such as how ontogenetic allometry facilitates evolutionary allometry, how size influences feeding performance and trophic niche, methodology in allometry and size estimation, and allometry in sexual selection. In doing so we highlight areas of particular need for future studies to better understand the role of allometry in evolutionary ecology.