The growth of protected cultivation in the world agriculture has driven crops traditionally cultivated in open field to enclosures, which, in turn, prevent the access of pollinators to flowers. Therefore, it became necessary to identify suitable pollinators for confined environments. Stingless bees have been pointed out in Brazil as the ideal pollinators for crop pollination under these conditions. Aiming to evaluate the viability of using two stingless bee species in a protected environment conditions, colonies of Melipona subnitida (D.) and Scaptotrigona sp. nov. were introduced in a greenhouse during the flowering of seeded (diploid) and seedless (triploid) mini watermelon (Citrullus lanatus T.) varieties. The feasibility of using these bee species was evaluated based on the adaptive and foraging behavior under the protected environment conditions. Melipona subnitida did not show any interest to the crop under the experimental conditions, stopped foraging trips and egg laying in a diapause-like stage. On the other hand, Scaptotrigona sp. nov. foragers were active and collected floral resources since the second day after their introduction. Moreover, the foragers of Scaptotrigona sp. nov. showed an essential behavior for mini watermelon pollination, because they visited staminates and pistillates flowers from both seeded and seedless genotypes for nectar collection. We concluded that M. subnitida did not adapt to the greenhouse mini watermelon cultivation under the experimental conditions and should not be used for pollination purposes in such a situation. Contrasting, Scaptotrigona sp. nov. adapted well to the greenhouse and should be preferred for greenhouse mini watermelon pollination.