Title

No evidence of nonlinear effects of predator density, refuge availability, or body size of prey on prey mortality rates

Keywords

linear response, predator density, predator-prey interactions, refuge, size effects, survival

Abstract

Predator density, refuge availability, and body size of prey can all affect the mortality rate of prey. We assume that more predators will lead to an increase in prey mortality rate, but behavioral interactions between predators and prey, and availability of refuge, may lead to nonlinear effects of increased number of predators on prey mortality rates. We tested for nonlinear effects in prey mortality rates in a mesocosm experiment with different size classes of western mosquitofish (Gambusia affinis) as the prey, different numbers of green sunfish (Lepomis cyanellus) as the predators, and different levels of refuge. Predator number and size class of prey, but not refuge availability, had significant effects on the mortality rate of prey. Change in mortality rate of prey was linear and equal across the range of predator numbers. Each new predator increased the mortality rate by about 10% overall, and mortality rates were higher for smaller size classes. Predator–prey interactions at the individual level may not scale up to create nonlinearity in prey mortality rates with increasing predator density at the population level.

Original Publication Citation

Simkins, R.M., and M.C. Belk. 2017. No evidence of nonlinear effects of predator density, refuge availability, or body size of prey on prey mortality rates. Ecology and Evolution 7:6119-6124.

Document Type

Peer-Reviewed Article

Publication Date

2017-06-28

Publisher

Ecology and Evolution

Language

English

College

Life Sciences

Department

Biology

University Standing at Time of Publication

Full Professor

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