The Bombus atratus native bumblebee is an important pollinator of agricultural interest crops. The study of their biology and their breeding in captivity has been the research topic of our group for more than a decade. Until now, the sources of food resources used by the colonies raised under the protocol of the research group were unknown, which is why this work was carried out. Colonies were located in the greenhouse and in the open field. A total of 105 pollen loads from worker corbiculae were collected: 85 from the greenhouse condition and twenty from the open field condition, which were processed using the acid acetolysis method. Thirty-six pollen types were identified, fifteen of which were named as important sources of pollen and nectar in the diet of B. atratus. 42% of the diet is made up of species of the Solanaceae family, 26% of the Myrtaceae family and 25% of different species of arvenses. The colonies located both in the open field and in the greenhouse share most of the sources of flower resources, however, some resources were more exploited than others due to their availability in each area. The flower resources that were most frequently found within the pollen loads were: Brassica rapa L., Raphanus sativus L., Trifolium repens L., Trifolium pratense L., Eucalyptus globulus Labill, Solanum quitoense Lam. y Solanum lycopersicum L. ; El abejorro nativo Bombus atratus es un importante polinizador de cultivos de interés agricola. El estudio de su biología y su cría en cautiverio ha sido el tema de investigación de nuestro grupo durante más de una década. Hasta el momento se desconocían las fuentes de recursos de alimento usadas por las colonias criadas bajo el protocolo del grupo de investigación, motivo por el cual se llevó a cabo el presente trabajo. Se ubicaron colonias en invernadero y en campo abierto. Se colectó un total de 105 cargas polínicas provenientes de corbículas de obreras: 85 de la condición de invernadero y veinte de la condición de campo abierto, las cuales se ...