Characterization of <i>Salix nigra</i> floral insect community and activity of three native <i>Andrena</i> bees

Salix nigra (black willow) is a widespread tree that hosts many species of polylectic hymenopterans and oligolectic bees the genus Andrena. The early flowering S. makes it an important nutritive resource for arthropods emerging from hibernation. However, since dioecious, not all insect visits will lead to successful pollination. Using both visual observation pan-trapping, we characterized community visited flowers assessed differences among male female trees as well chemical drivers influenced composition across 3 years. We found consistently supported higher diversity insects than only three species, Andrena spp., sexes. Additionally, nigrae, which was occurred more on flowers, correlated strongly volatile cues. This suggests cross-pollinators cue into specific aspects floral scent, but visitors driven by cues yellow pollen. Through time, activity two remained stable, A. nigrae less in 2017 when bloomed earlier other When native bee emergence does synchronize with bloom, appears be diminished could threaten subsist single host. Despite its productivity depends small fraction are threatened competition, rather rapidly changing conditions host-insect asynchrony.