Phenotypic Gambit Invoke Optimization of Behavior Mimic Assumed Stabilizing Selection Deduce Predictions From Hypothesized Currency of Fitness Specify Quantitative Test
Model for Optimal Behavior Strategy Set: Possible Behaviors Find the “Best Strategy,” Given Hypothesis Constraints: Environmental, Physiological Define Problem Hypothesis: Behavior Currency of Fitness
Basic Methods Predict Focal Individual’s Behavior: Does Behavior of Other Individual (s) Matter? Does Behavior of Other Individual (s) Matter? NO: “Standard Optimization;” Find Maximal Currency of Fitness YES: Game Theory; Find Evolutionary Stable Strategy
Standard (Simple) Optimization
a* Optimal Behavior?
Standard (Simple) Optimization a* Optimal Behavior?
Caveat Don’t Anticipate “Perfection” Naïve Pan-Selectionism Does Hypothesis Advance Understanding of Processes Shaping Diversity of Behavior in Nature
Individual Behavior Crows Feeding on Whelks: references R. Zach (1978) Selection and dropping of whelks by Northwestern crowsR. Zach (1978) Selection and dropping of whelks by Northwestern crows, Behaviour, 67, R. Zach (1978) Selection and dropping of whelks by Northwestern crows R. Zach (1979) Shell dropping: Decision-Making and optimal foraging in Northwestern crows,R. Zach (1979) Shell dropping: Decision-Making and optimal foraging in Northwestern crows, Behaviour, 68, 106 – 117 R. Zach (1979) Shell dropping: Decision-Making and optimal foraging in Northwestern crows,
Crows Feeding on Whelks Northwestern crow (Corvus caurinus) Whelk (Thais lamellosa) Mollusc Search intertidal zone Fly to rocks, Drop prey Repeat, Shell breaks
Crows Feeding on Whelks Crows choose larger prey ~ Uniform size At rocks, Fly straight up, Drop whelk (Re-drop) Optimal foragers? “Optimize” H, height?
Crows Feeding on Whelks Number of drops versus height H Large prey break easier Constraint on problem
Outline Model Hypothesis: Selection favors dropping whelk from height minimizing energetic cost to forager Individual Behavior: No Social Interaction Translate Height [H] into currency of fitness [Cost] Find H* where Cost minimal
Model: E = kHN E: Energy cost (Currency) H: Drop height (Decision) N(H): No. drops k > 0 constant Objective Function a = 15.9; b = 1.2
Deduce Prediction Derivative dE/dH = 0 H* = 5.6 m Minimizes cost
Prediction H = 5.6 m Mean close to H* Some variation Issue: Gain some understanding?