Niche dynamics are widely thought to shape the breadth of floral resources in plant-pollinator communities, which can influence resource partitioning and promote coexistence and ecosystem stability. Bumble bees’ visitation patterns to flowers can be influenced by both interspecific and intraspecific competition, and fluctuating environmental conditions can affect the foraging abilities of these bees. We examined whether the foraging behavior of bumble bees in the Colorado Rocky Mountains was consistent with the relative abundance of floral resources and how ecologically relevant variables like temperature and day of year related to these patterns. We found that visits to available flowers deviated from what would be expected by relative abundance, with evidence for preference and avoidance across all bumble bee species as well as when we isolated the three most common species in our system: B. appositus, B. bifarius, and B. flavifrons. Overall niche breadth also declined as the season progressed, likely in relation to variation in temperature, floral richness, and floral abundance. Our results illustrate that competition both within and across bumble bee species simultaneously influence niche dynamics and bumble bees have the ability to respond to environmental changes with flexible selectivity in floral partners. Understanding these and other possible drivers of interaction patterns in bumble bee communities can provide valuable insight into how a rapidly changing environment might disrupt bumble bee health, persistence, and function in these and other ecosystems.
.png)
