Introduced plants may be important foraging resources for honey bees and wild pollinators, but how often and why pollinators visit introduced plants across an entire plant community is not well understood. Understanding the importance of introduced plants for pollinators could help guide management of these plants and conservation of pollinator habitat. We assessed how floral abundance and pollinator preference influence pollinator visitation rate and diversity on 30 introduced vs. 24 native plants in central New York. Honey bees visited introduced and native plants at similar rates regardless of floral abundance. In contrast, as floral abundance increased, wild pollinator visitation rate decreased more strongly for introduced plants than native plants. Introduced plants as a group and native plants as group did not differ in bee diversity or preference, but honey bees and wild pollinators preferred different plant species. As a case study, we then focused on knapweed (Centaurea spp.), an introduced plant that was the most preferred plant by honey bees, and that beekeepers value as a late-summer foraging resource. We compared the extent to which honey bees vs. wild pollinators visited knapweed relative to co-flowering plants, and we quantified knapweed pollen and nectar collection by honey bees across 22 New York apiaries. Honey bees visited knapweed more frequently than co-flowering plants and at a similar rate as all wild pollinators combined. All apiaries contained knapweed pollen in nectar, 86% of apiaries contained knapweed pollen in bee bread, and knapweed was sometimes a main pollen or nectar source for honey bees in late summer. Our results suggest that because of diverging responses to floral abundance and preferences for different plants, honey bees and wild pollinators differ in their use of introduced plants. Depending on the plant and its abundance, removing an introduced plant may impact honey bees more than wild pollinators.

The dataset was collected in two phases.

First, in 2017, data was collected on visitaiton rates and diversity of pollintors visiting plants in three meadows in upstate New York. Data was collected throughout the flowering period. Please see the publication for details on data collection.

Second,  in 2018, data was collected on knapweed pollen and nectar collection in 22 apiaries across New York. Each apiary was visited twice, nectar and pollen samples were taken from two hives per apiary. For each sample, we counted the number of knapweed pollen grains per 300 total grains in a subsample of the substrate (nectar or pollen). Also, in 2018, we collected insects visiting knapweed in 7 fields across New York. Please see the publication for details on data collection.

Please note that to preserve confidentiality, we have rounded the lat lons of apiaries to a tenth of a decimal place. Therefore, these data should NOT be used for any type of analysis that involves quantifying land use or land cover at the landscape scale. 

I have included four metadata files (.rtfs) to describe the table attributes for the four datasets.