“Seasonal food scarcity prompts long-distance foraging by a wild social bee”

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Nathaniel S. Pope and Shalene Jha

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Seasonal food scarcity prompts long-distance foraging by a wild social bee

A yellow-faced bumble bee (Bombus vosnesenskii) visiting a Zinnia flower in the Central Valley of California.
(Credit: Shalene Jha)

Across the globe, pollinating insects are essential for the persistence of plant communities and provide services that are critical for the production of many crops, worth an estimated $200 billion globally in enhanced yields each year. Bees—a large and diverse group of insects that primarily depend on pollen and nectar from flowering plants—are some of the most widespread and effective pollinators. Despite their ubiquity and importance to humans, little is known about the spatial range at which wild bees forage for food, or how they alter their behavior in landscapes where flowering plant density shifts across the year. This is due, in part, to the difficulties of tracking the movements of flying insects in the wild.

In this study, graduate student Nathaniel Pope and Dr. Shalene Jha from the University of Texas at Austin collected wild bumble bees and used genetic markers to identify sister bees as they foraged across multiple landscapes in the chaparral of central California. Using the bees’ genetic information, Pope and Jha mapped out the foraging patterns of each colony across different time periods. They found that bumble bees are more sophisticated foragers than previously expected; bumble bees choose to fly longer distances to reach higher density patches of flowers, but only in the summer months when flowering resources are more limited. Overall, the results from the study suggest that potential alterations to plant flowering due to global change could dramatically alter bumble bee movement and pollination services. Further, the research suggests that current pollinator conservation efforts should consider targeting late-season floral resources, when bees may be most stressed by long-distance foraging.