It specializes in feeding on the highly poisonous Toxicoscordion venenosum, the meadow deathcamas, and close relatives.

They named the species assuming that was primarily or exclusively a pollinator of that genus, when in fact they mostly visit Toxicoscordion flowers and the bee collected was an outlier.

[10] The female is about 10–13 millimeters in length with a black body and reddish to creamy white hairs.

[12] A. astragali is different than other American Andrena in the western United States by being larger and having two toothlike projections on the labrum, the flap in front of the mouth parts.

[17] Scientists studying the interactions hypothesize that the evolution of tolerance for the poisons by the death camas bee is an adaptation to deter predators and/or parasites.

[18] A study of Toxicoscordion paniculatum flowers found that they are also quite dependent on pollination by death camas bees.