Characterization of Salix nigra floral insect community and activity of three native Andrena bees

Data was collected using a combination of specimen collection with hand trapping, visual observations, and pan traps as described in "The very handy manual: how to catch and identify bees and manage a collection" (https://www.usgs.gov/media/files/how-catch-and-identify-bees-and-manage-a-collection). Floral VOCs were collected using a using a dynamic headspace method with nylon oven bags which had polytetrafluoroethylene (PTFE) ports that were fixed and connected to chemical traps consisting of 65 mm long and 3 mm internal diameter glass tubes packed with 20 mg of Super Q adsorbent (80/100 mesh size, DVB/ ethylvinylbenzene polymer, Alltech Associates Inc., Deerfield, IL, USA). VOC samples were then analyzed with a Thermo Trace 1310 GC coupled to a Thermo ISQ MS with electron ionization (EI) at 70.0 eV at 250 °C. Phenolic glycoside chemistry data was obtained from flash frozen floral and leaf tissue analyzed on UHPLC [Waters Acquity I-Class UPLC with a photodiode array detector (PDA) and a 3100 SQ mass spectrometer (MS), Milford, MA, USA] with commercially available standards of salicin (Sigma-Aldrich), and salicortin, tremuloidin, and tremulacin that had been previously isolated and purified from aspen foliage.