Modeling metabolic costs of allelochemical ingestion by foraging herbivores.

A mathematical model of intermediary metabolism of allelochemicals by vertebrate herbivores is presented and used to quantify the metabolic costs of detoxification. Conjugation with glucuronic acid and maintenance of acid-base status causes catabolism of amino acid and is shown to result in loss of body protein and depletion of glucose. An interaction between allelochemical dose and nutrient status is found, and the ratio of allelochemical to nutrient absorption rate defines the tolerance of the animal to absorbable allelochemical concentration in foods. The interaction is nonlinear and the ecological implications of this for foraging behavior and diet choice are discussed.