Top-down effects of intraspeciflic predator behavioral variation

Area of Science:

• Ecology
• Behavioral Ecology
• Community Ecology

Background:

• Among-individual variation in predator traits is common but rarely studied in population dynamics.
• The spatial variation in predator trait effects on prey populations remains largely unexplored.

Purpose of the Study:

• To investigate how predator among-individual variation in functional traits influences prey populations and communities.
• To determine the extent to which these effects vary spatially across different habitat complexities.

Main Methods:

• Experimental manipulation of Chinese mantis (Tenodera sinensis) density and behavioral trait variability.
• Assessment of impacts on prey (arthropods > 4 mm) and plant biomass in old fields with varying habitat complexity.

Main Results:

• Predator behavioral variability affected prey biomass only in structurally complex habitats, with effects dependent on mantis density.
• Behaviorally variable mantis groups decreased prey biomass by 40.3% in high-complexity, high-density plots.
• Behavioral variability and low habitat complexity increased ant biomass by 881%, altering prey community composition.

Conclusions:

• Among-individual trait variation significantly shapes species-rich prey communities.
• The effects of predator trait variation are contingent upon predator density and habitat complexity.
• Incorporating ecological diversity, including trait variation, reveals previously unrecognized food web dynamics.