We’ve put out water for the honey bees living in our backyard, but they seem to prefer dirty water from puddles around the yard. They specifically seem to favour the moist dark compost soil in our raised garden beds.
Does the soil give off some sort of fake pheromone that attracts the bees? I didn’t know, so I looked up “water” in my excellent 1947 edition of The ABC and XYZ of Bee Culture (the only edition of the book I could afford) and I learned that the bees bring in more water in the spring during brood-rearing and less water as the honey flow peaks. But more to the point, the bees drink from compost piles (and composted soil) because the water there is warmer than water left in a dish. The bees are able to absorb warm water faster than cold water. So it’s not the stink of the compost that attracts them. It’s the warmth.
I think it’s fair to conclude, from this instance and everything else I’ve observed, that whatever honey bees do, they do it with the utmost efficiency.
UPDATE (a few hours later): The warm water theory doesn’t hold much water. Here’s a shot of the bees drinking freezing cold water leaking from my garden hose all day.
P.S., Read the comments for more thoughts on this topic. The bees have to be attracted to something other than simply warm water.