Bumblebee flight distances in relation to the forage landscape

Area of Science:

• Ecology
• Behavioral Ecology
• Pollination Biology

Background:

• Foraging range is critical for central place foragers like bees.
• Estimating bee foraging distances is vital for colony success and gene flow.
• Forage distribution significantly impacts foraging distance, yet is difficult to quantify.

Purpose of the Study:

• To quantify bumblebee (Bombus terrestris) foraging distribution in an agricultural landscape.
• To correlate foraging distances with spatial forage availability.
• To assess the influence of landscape heterogeneity on bumblebee foraging.

Main Methods:

• Mass-marking of bumblebee foragers departing from experimental colonies.
• Analysis of pollen loads from returning bumblebee foragers.
• Integration of empirical bee data with a high-resolution forage landscape map derived from remote sensing.

Main Results:

• Bumblebees foraged at least 1.5 km from their colonies.
• The proportion of foragers visiting a field decreased linearly with distance.
• Forage availability varied significantly within 500m but was consistent beyond 1km.

Conclusions:

• Bombus terrestris foraging scale can buffer against local forage heterogeneity.
• Colony success may be highly variable for bee species with shorter foraging ranges.
• Landscape-scale forage mapping is crucial for understanding bee ecology.