Taking fear back into the marginal value theorem: the rMVT and optimal boldness

Area of Science:

• Behavioral Ecology
• Foraging Theory
• Risk-Sensitive Behavior

Background:

• Animals foraging in varied habitats must make strategic movement decisions.
• Charnov's Marginal Value Theorem (MVT) predicts optimal foraging time but omits predation risk.
• Brown's giving-up density (GUD) theory addresses risk but is abstract.

Purpose of the Study:

• To introduce the risk-sensitive Marginal Value Theorem (rMVT) as a generalization of the MVT.
• To incorporate predation risk into a graphical and specific foraging model.
• To provide a framework for understanding how risk influences foraging decisions.

Main Methods:

• Formal introduction of the rMVT, a mathematical model.
• Comparison of rMVT predictions with GUD theory under various risk scenarios.
• Application of rMVT to predict optimal boldness and behavioral responses to risk.

Main Results:

• The rMVT successfully integrates various forms of predation risk.
• Optimal foraging strategies can respond oppositely to increased risk levels depending on risk type.
• The model predicts that animals should generally be bolder in riskier habitats.

Conclusions:

• The rMVT offers a more comprehensive and applicable framework for studying foraging under risk.
• Predation risk significantly impacts optimal foraging strategies and movement decisions.
• The rMVT can explain differential behavioral responses observed in natural and experimental settings.