In a new paper in Ecology Letters, we use the diverse shape shifting abilities of pelagic invertebrates to test competing theories of how metabolism scales with body size. Comparing the divergent predictions from models built on internal resource transport networks and those based on limits set by surface area exchange, with data from over 250 pelagic animals, we find strong support for the surface area dependent models.
Metabolism fuels all of life’s activities, from biochemical reactions to ecological interactions. What controls the relationship between metabolic rate (respiration) and body size has been debated for over 75 year. According to two fiercely debated theories, body size affects metabolism via limits set by material transport across external body surfaces, or through internal transport networks. We exploit the fact that when shape changes during growth, for example by elongating or body flattening, these theories make opposing predictions. Since pelagic invertebrates exhibit highly variable intraspecific metabolic scaling, rely upon large portions of their surface for exchange, and shape shift during ontogeny, they make an excellent case to test the divergent predictions of the models. Analysing data from over 250 diverse pelagic species we find that the degree of shape shifting closely relates to the scaling of metabolic rates, supporting surface-area dependent theory of metabolism, while contradicting predictions based on internal transport networks.
The paper can be read here
Reference: Hirst, Glazier, Atkinson (2014) Body shape shifting during growth permits tests that distinguish between competing geometric theories of metabolic scaling. Ecol Lett doi: 10.1111/ele.12334
