Pollen load assessment
We removed pollen from pollinators’ bodies with Fuchsin jelly (Kearns, 1993), melted the jelly onto slides (hereafter “pollinator slides”), and visualized pollen using a light microscope. We also made slides of pollen from the anthers of the plant species on which each pollinator was caught (hereafter “anther slides”). We compared pollen on the anther slides to pollen on the pollinator slides to determine the number of grains that were conspecific for each pollinator. To identify heterospecific pollen to species we compared pollen on pollinator slides to pollen made from the anthers of other flowering plants at each site. We cross-referenced pollen identifications with photos from the Global Pollen Project (globalpollenproject.org).