Large Differences in Herbivore Performance Emerge From Simple Herbivore Behaviours and Fine-Scale Spatial...

Area of Science:

• Ecology
• Chemical Ecology
• Insect Behavior

Background:

• Phytochemicals in plants exhibit diverse spatial patterns within tissues.
• Spatial distribution of plant toxins influences herbivore fitness, but effects on foraging are not well understood.

Purpose of the Study:

• To investigate how spatial variance and clusteredness of plant toxins affect herbivore foraging and performance.
• To determine the role of toxin spatial patterns in herbivore dietary experience.

Main Methods:

• Manipulated spatial variance and clusteredness of toxins in a synthetic diet landscape.
• Monitored individual caterpillar feeding and movement behavior using cameras throughout larval development.
• Utilized empirically parameterized individual-based models to analyze foraging decisions.

Main Results:

• Caterpillars performed worse on diets with lower spatial variance and more clustered toxins.
• Reduced performance was linked to decreased food intake, increased movement, higher toxin ingestion, and impaired acclimation.
• Movement away from less toxic food, not towards it, drove size-dependent effects of toxin clusteredness.

Conclusions:

• The spatial arrangement of phytochemicals, beyond average concentration, significantly impacts herbivores.
• Herbivore foraging behavior and physiological responses interact with toxin spatial patterns, affecting overall performance.