Predators risk injury too: the evolution of derring-do in a predator–prey foraging game

Abstract

Derring-do is how aggressive a predator is in stalking and capturing prey. We model predator–prey interactions in which prey adjust vigilance behavior to mitigate risk of predation and predators their derring-do to manage risk of injury from capturing prey. High derring-do increases a predator's likelihood of capturing prey, but at higher risk of injury to itself. For fixed predator derring-do, prey increase vigilance in response to predator abundance, predator lethality, and predator encounter probability with prey and decrease vigilance with their own feeding rate; there is a humped-shaped relationship between prey vigilance and effectiveness of vigilance. For fixed prey vigilance, predators increase derring-do with the abundance of prey and predator lethality and decrease it with benefit of vigilance to prey and level of prey vigilance. When both prey and predator are behaviorally flexible, a predator–prey foraging game ensues whose solution represents an evolutionarily stable strategy (ESS). At the ESS, prey provide themselves with a public good as their vigilance causes predators to decrease derring-do. Conversely, predators have negative indirect effects on themselves as their derring-do causes prey to be more vigilant. These behavioral feedbacks create negative intra-specific interaction coefficients. Increasing the population size of prey (or predators) now has a direct negative effect on the prey (or predators). Both effects help stabilize predator–prey dynamics. Besides highlighting a common way by which predators may experience a food-safety tradeoff via dangerous prey, the model suggests why natural selection favors even small defensive measures by prey and hulky predators.

Keywords:

• derring-do or predator daring
• ecology of fear and fear management
• foraging games; predator–prey interactions
• risk of injury and risk management
• tradeoffs of food and safety

Acknowledgements

This work was supported in part by a Prof. Rohamimoff Travel Grant for Young Scientists from the Israel-United States Binational Science Foundation awarded to Keren Embar. Keren Embar undertook this project while visiting UIC where her enthusiasm for science and nature proved infectious and wonderful for the entire Brown lab. The model and ideas benefited greatly from an anonymous reviewer, discussions with Christopher Whelan, and feedback from the Brown and Kotler labs. This work was also supported by grants from the National Science Foundation, and US–Israel Binational Science Foundation. This is publication number 910 of the Mitrani Department of Desert Ecology.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported in part by a Prof. Rohamimoff Travel Grant for Young Scientists from the Israel–United States Binational Science Foundation awarded to Keren Embar; the National Science Foundation; US–Israel Binational Science Foundation.