In this lecture, we continue using an opportunity cost perspective to predict optimal foraging behavior of predators. We pivot from a review of the marginal value theorem (and the patch model for patch residence times) from the last lecture to an introduction of the prey model of optimal diet choice. This allows us to introduce the profitability-ranking solution of the prey model. After exploring experimental evidence for the validity of this solution, we turn attention to how physiological constraints and shift animals to other diet portfolios. We give examples from sodium limitation in moose, water limitation in spiders, and ballast constraints in shorebirds. Overall, we come to the conclusion that there are many drivers of foraging behavior, and behavioral ecologists choose different model organisms specially to allow for focusing on the effect of each one.
Topic highlights:
- Review of the patch model, optimal patch residence times, and the marginal value theorem
- Introduction of the prey model of predator diet choice
- Solution of the prey model with profitability ranking and opportunity cost thresholding
- Experimental validation of the prey model
- Effect of physiological constraints on optimal foraging behavior
- Sodium-limited moose example
- Water-limited spider example
- Ballast-constrained molluscivore example
Important terms: patch, patch residence time, diet choice/prey choice, marginal returns/gain, diminishing marginal returns, opportunity cost, optimal foraging theory, rate maximization, Marginal Value Theorem (MVT), The Prey Model, diet choice, zero–one rule, profitability, profitability ranking, gizzard, partial preferences
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