Bees and all living creatures NEED salt. Sometimes they can get it on their own, sometimes not. Some people put out dry salt in a plate or pan for bees, others put it into water. Myself, I tend to give them a dry "salt lick" as well as putting it into the sugar syrup when I have to feed them. I normally boil water to help disolve sugar in the syrup so I add about a teaspoon full to about 1.5 gal of water to help it boil faster. The bees tend to suck it down pretty fast and use it.