Organismal stoichiometry: Quantifying non-independence among food components

Ecological stoichiometry represents an important innovation in ecological modeling, both in its recognition of the causal role of species-specific regulatory physiology in high-level ecological processes and in its adoption of multiple-substance models. In this paper we provide an overview of a geometrical approach for studying the exchange of nutrients between individual organisms and their environment that, although developed independently, shares much in common with ecological stoichiometry and might, we believe, contribute to its further development. In particular, the framework focuses on identifying food components that interact in their effects on organismal nutrition, and quantifying the consequences of these interactions for ingestive regulation,. post-ingestive processing, and animal performance. We illustrate our approach using data,for terrestrial herbivores (insects) and discuss the potential relevance of these data for models of ecological processes.