Applicability of Five Diet-selection Models to Various Foraging Challenges Ruminants Encounter
It is common knowledge that ruminants do not forage at random, but select a diet from the plants available to them. We believe foraging environments present at least five problems or challenges to ruminants selecting dietary items: (1) variation among dietary items in kind and amount of nutritional constituents, (2) variation among potential dietary items in kind and amount of chemical defenses, (3) plant morphological defenses, (4) temporal and spatial variation in the quantity and quality of forage, and (5) exposure of ruminants to unfamiliar foraging environments. Our objective is to assess the ability of five explanations of diet selection to provide insights into the responses of ruminants to these challenges. The models are: (1) endogenously-generated hungers (euphagia), (2) immediate sensory consequences (hedyphagia), (3) body morpho-physiology and size (morphophysiology), (4) learning through foraging consequences (learning), and (5) nutritional optimization (optimal foraging). We make the assessment by first describing the diet-selection challenges and then discussing the models and their applications to the challenges.
Provenza, Frederick D., David F. Balph. 1990. Applicability of Five Diet-selection Models to Various Foraging Challenges Ruminants Encounter. Ecological Sciences 20: 423-460.