Temperature and prey morphology influence attack rate and handling time in a predator-prey interaction

Functional responses describe how the proportion of prey consumed by a predator changes as prey density changes. For predators consuming a single prey species, functional responses are determined by two parameters: attack rate and handling time. These parameters may be influenced by morphological and behavioral differences in prey stemming from interspecific or environmentally-driven processes. Here we investigate how interspecific morphological differences and changes in movement rate impact a predator's functional response. Using a flatworm predator (Stenostomum virginianum) consuming either Paramecium aurelia or P. multimicronucleatum we show that movement rate changes significantly with temperature, leading to changes in attack rate. We also show how body size affects the amount of time predators require to handle prey. We fit a mechanistic functional response model to demonstrate how changes in attack rate and handling time affect overall rates of predation. Our results demonstrate that S. virginianum attack rates are greater for P. aurelia than P. multimicronucleatum. In addition, higher temperature increases S. virginianum attack rates on both species, and reduces the time needed to handle P. aurelia. These differences in predation rate appear related to prey species' traits, and the temperature-mediated changes in these traits, highlighting the complex processes that underpin predator-prey interactions.

Automated summary

Functional responses in predator-prey interactions are influenced by attack rate and handling time, which can be affected by morphological differences, behavior, and environmental factors. Research on a flatworm predator consuming different prey species shows that movement rate changes with temperature, impacting attack rate. Predation rates are higher for certain prey species and increase with temperature, highlighting the complex nature of predator-prey interactions.