Functional responses are maximized at intermediate temperatures.

Area of Science:

• Ecology
• Predator-prey dynamics
• Ecological modeling

Background:

• Functional responses quantify consumer foraging rates relative to resource density.
• Controversy exists regarding the influence of temperature and body size on functional response parameters like attack rate and handling time.

Purpose of the Study:

• To investigate the effects of temperature, consumer mass, and resource mass on functional response parameters.
• To analyze the largest compilation of functional response curves to date.
• To improve ecological modeling by incorporating nuanced effects of environmental and biological factors.

Main Methods:

• Compiled and analyzed 2,083 functional response curves across diverse taxa and habitats.
• Accounted for experimental arena size, interaction dimensionality, and consumer taxon.
• Utilized statistical models to assess the independent and interactive effects of temperature, consumer mass, and resource mass.

Main Results:

• Both space clearance rate and handling time exhibit a unimodal response to temperature, optimized at intermediate levels.
• Larger consumers and smaller resources lead to higher and steeper functional responses.
• Consumer and resource body masses act independently, outperforming mass ratio models.
• Temperature and mass effects are taxon- and dimensionality-dependent.

Conclusions:

• Functional responses are not universally monotonic with temperature or body size.
• Ecological models should incorporate unimodal temperature effects, independent body mass influences, and taxonomic identity for greater accuracy.
• Understanding these complex interactions is vital for predicting responses to global climate change and for robust food web dynamics.