Foraging rates from metabarcoding: Predators have reduced functional responses in wild, diverse prey communities

Area of Science:

• Ecology
• Predator-Prey Dynamics
• Behavioral Ecology

Background:

• Functional responses quantify predator foraging rates and are crucial for ecological processes.
• Lab experiments dominate functional response research, but their real-world applicability is uncertain.
• Multispecies functional response experiments are challenging, leaving interactions in diverse prey environments poorly understood.

Purpose of the Study:

• To develop a novel method for estimating wild predator foraging rates using metabarcoding data.
• To determine the functional responses of wild wolf spiders across 27 prey families in their natural habitat.
• To compare field-based functional responses with those derived from laboratory settings and investigate the impact of multiple prey types.

Main Methods:

• Development of a new metabarcoding-based technique to quantify predator diets and estimate foraging rates in the wild.
• Application of the novel method to analyze the diets of wild wolf spiders.
• Estimation of functional response curves based on field data from wild wolf spiders foraging on 27 prey families.

Main Results:

• Field-based functional responses for wild wolf spiders were significantly lower than those observed in laboratory experiments.
• Contrary to expectations, the presence of alternative prey sometimes led to increased foraging rates, indicating complex ecological interactions.
• The study provides the first field-derived functional responses for a wild predator across a wide range of prey types.

Conclusions:

• Laboratory-based functional responses may not accurately reflect foraging behavior in natural ecosystems.
• Predator-prey interactions in the wild can be more complex than previously assumed, with potential for non-additive effects of multiple prey types.
• The developed metabarcoding method offers a powerful tool for studying foraging ecology and functional responses of wild predators, advancing ecological research.