Please tell me what do you think :) The photo is from Santander, Colombia. I didn’t take any closeups photos 😞, but these were little bees, like 5 x 1 mm. The tube didn’t seem man-made, it was indoors and the owner of the house said that they are stingless, since no one has been stung.
If these bees are definitely stingless, they're members of the Meliponini tribe, which discounts those Halictid IDs. I'm only familiar with Nearctic Halictidae, but practically every species I'm aware of is a ground nester. The rare exceptions prefer hollow twigs, so I'm fairly confident it's not in Halictidae.
The nest entrance does appear to be consistent with a few Meliponine genera, especially Tetragonisca. Discoverlife only lists T. angustulata as appearing in Colombia, but notes that the name is applied to several undescribed congeners. A quick look at this species' nests makes me fairly confident that the bees in this photo are a Tetragonisca species.
Sadly neotropic bees like Meloponini are extremely under-researched. I'm personally very unfamiliar with the tribe, luckily this genus in particular seems relatively well-known.
Looks like the family Halictidae to me. Known as a sweat bee. Maybe Lasioglossum zephyrus?