Callonychium petuniae was reported as an oligolectic bee species on three species of the solanaceous genus Petunia s. l. (Calibrachoa ovalifolia (Miers) Stehmann & Semir, Calibrachoa excellens (R.E. Fr.) Wijsman, and Petunia integrifolia (Hook.) Schinz & Thell.) (Cure & Wittmann, 1990).