Changes in Foraging behavior after Competitive Release vary across bee species
Abstract
Species competition is a key ecological process determining species coexistence and community assembly. In plant-pollinator systems, understanding how pollinators respond behaviorally to competitive interactions is critical to identifying the mechanisms that shape pollinator niche breadth and the structure of plant-pollinator communities. Theoretical models predict that changes in foraging behavior (adaptive foraging) mitigates floral resource overlap and facilitates coexistence in the presence of competitors. However, empirical tests of bee foraging responses in the absence of competitors remain limited. Adaptive foraging predicts, pollinators will expand or contract their use of floral resources in response to competition. However, how pollinators respond to competition may also vary across species due to their differences in sociality, foraging range and size. Here, we investigated adaptive foraging responses across three native bee species, Bombus, Osmia, and Andrena, in response to a natural fluctuation in the density of Apis mellifera, a dominant introduced competitor. The study took place in plant communities at the McLaughlin Natural Reserve in California where honeybee abundance declined significantly (~75%) Between 2021 and 2022, providing a unique opportunity to assess shifts in foraging behavior under reduced competitive pressure. We sampled pollen loads from 30-40 individual bees per species/year and constructed individual-level networks to evaluate shifts in foraging specialization, interaction strength, pollen load size and diversity. The results reveal shifts in pollen load diversity in the absence of competitors, but the direction varies by bee species. Network metrics further indicate shifts in individual specialization and weighted closeness when honeybee density is low. Combined, these results suggest significant changes in bee foraging patterns mediated by competitor density, with potential consequences for pollination success. Overall, this work contributes to a growing empirical understanding of how competition shapes pollination networks and provides insights into the role of individual behavioral shifts in helping maintain plant-pollinator community resilience and stability.
Start Time
15-4-2026 10:00 AM
End Time
15-4-2026 11:00 AM
Room Number
311
Presentation Type
Oral Presentation
Presentation Subtype
Grad/Comp Orals
Presentation Category
Science, Technology, and Engineering
Student Type
Graduate
Faculty Mentor
Arceo Gomez
Changes in Foraging behavior after Competitive Release vary across bee species
311
Species competition is a key ecological process determining species coexistence and community assembly. In plant-pollinator systems, understanding how pollinators respond behaviorally to competitive interactions is critical to identifying the mechanisms that shape pollinator niche breadth and the structure of plant-pollinator communities. Theoretical models predict that changes in foraging behavior (adaptive foraging) mitigates floral resource overlap and facilitates coexistence in the presence of competitors. However, empirical tests of bee foraging responses in the absence of competitors remain limited. Adaptive foraging predicts, pollinators will expand or contract their use of floral resources in response to competition. However, how pollinators respond to competition may also vary across species due to their differences in sociality, foraging range and size. Here, we investigated adaptive foraging responses across three native bee species, Bombus, Osmia, and Andrena, in response to a natural fluctuation in the density of Apis mellifera, a dominant introduced competitor. The study took place in plant communities at the McLaughlin Natural Reserve in California where honeybee abundance declined significantly (~75%) Between 2021 and 2022, providing a unique opportunity to assess shifts in foraging behavior under reduced competitive pressure. We sampled pollen loads from 30-40 individual bees per species/year and constructed individual-level networks to evaluate shifts in foraging specialization, interaction strength, pollen load size and diversity. The results reveal shifts in pollen load diversity in the absence of competitors, but the direction varies by bee species. Network metrics further indicate shifts in individual specialization and weighted closeness when honeybee density is low. Combined, these results suggest significant changes in bee foraging patterns mediated by competitor density, with potential consequences for pollination success. Overall, this work contributes to a growing empirical understanding of how competition shapes pollination networks and provides insights into the role of individual behavioral shifts in helping maintain plant-pollinator community resilience and stability.
