White-bearded Manakins sally upwards for fruit and insects. The diet is little studied except on Trinidad and in French Guiana, from which regions over 100 species of fruit are reported in the diet (Snow 1962, 2004, Kirwan and Green 2011), primarily Melastomataceae (47-65% of all fruits taken), but also from Euphorbiaceae, Moraceae, and Rubiaceae. Other fruit in the diet those from include species of Ulmaceae, Meliaceae, Burseraceae, Araliaceae, and Amaranthaceae (southeastern Brazil; Galetti and Pizo 1996).
The range of arthropods consumed by White-bearded Manakins is less well known, but includes spiders, Coleoptera, Diptera, Formicidae (ants), Hemiptera, Hymenoptera (wasps), and Isoptera (termites) (Snow 1962, Lopes et al. 2005, Lima et al. 2010). Willis (1984) reported that White-bearded Manakin regularly attends army ant swarms.