Influence of an invasive bush on native bee communities adjacent to intensive agriculture

Bee diversity is decreasing due to habitat loss and agricultural intensification, placing plants that require pollinators at risk.  Within intensive agricultural landscapes, degraded forest patches contain much of the surrounding biodiversity, but also high numbers of invasive plant species.  Lonicera maackii is an invasive bush found in forest patches, offering nectar-rich flowers to the bee community.  To evaluate the impact that floral resources of L. maackii have on bee communities, we performed a floral manipulation study using sentinel plants. In spring of 2013 and 2014, 100 meters of honeysuckle flower buds were removed (treatment) in a paired-plot design along five north-facing temperate forest patch edges adjacent to soy or corn monocultures in southern Ohio and Indiana.  Fluorescently painted pan traps and obligatory outcrossing cucumber (Cucumis sativus) sentinel plants were placed at distance classes up to 200 meters from the forest edge to sample the bee community and measure pollination services, respectively.  In 2013, pan traps sampled 1059 bees, comprising 80 species from 20 genera.  Total bee abundance, species richness, and species composition were not different between treatments. However, sentinel cucumber plants (N=464) demonstrated a decrease in the number of seeds per fruit within treatment plots compared to controls in 2013 and 2014.  This preliminary data suggests that floral resources of the invasive bush, L. maackii, in high densities along forest edges causes shifts in the foraging bee communities that result in better pollination services to vegetable cucumber plants outside the forest patch.