Diversity and composition of pollen collected by the sunflower specialists Melissodes agilis and M. trinodis

Wild bee communities in cultivated sunflowers are often dominated by specialists (= oligoleges), including Melissodes agilis Cresson and M. trinodis Robertson. Available data on plant associations for M. agilis and M. trinodis suggest the most visited plants are almost exclusively Asteraceae, with several taxa common to both bees including thistle (Cirsium spp.), goldenrod (Solidago spp.), rosinweed (Silphium spp.) and ironweed (Vernonia spp.). Some plant taxa that appear visited by only M. agilis or M. trinodis, though it is not clear whether the data reflect a true foraging preference. Pollen washed from bees collected in North Dakota during 2019 and 2020 was analyzed via DNA metabarcoding to: (1) identify which non-Helianthus plants are being visited, (2) determine whether the bee species differ in the diversity or composition of plant resources used, (3) and test whether time (or surrounding habitat) influences plant pollen collected. Understanding non-Helianthus plants used by Melissodes spp. could help inform where sunflower or other crops are located on the landscape, influence management of surrounding vegetation, or encourage the use of additional floral resources to support pollinator populations.