Formulating and testing a partially specified dynamic energy budget model

Dynamic energy budget models relate phenomena at many levels of ecological organization and can provide quantitative links from individual physiology to population, community, and ecosystem dynamics. A prerequisite for making these links is an empirically tested model of growth and reproduction for individual organisms in a temporally variable environment. We construct a model that is applicable to organisms with indeterminate growth. By applying a recent statistical approach attributable to S. N. Wood, we use the model to infer the size dependence of feeding rates and of energy allocation to growth vs. reproduction for Daphnia from new laboratory data on growth and egg production. The implied feeding rates are consistent with independent measurements. With one additional assumption, respiration rates can be predicted; they scale with size in a manner consistent with previous measurements of respiration allometry. These findings support the use of inverse methods to determine physiologically based functions and parameters for subsequent use in population and ecosystem models