The Beekeeper’s Companion Since 1861
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Plain Talk Beekeeping: The Basics … and then some

Moisture Management in the Bee Colony: By both bees and beekeepers…

- December 1, 2022 - James E. Tew - (excerpt)

A good crop of water

When is the last time another beekeeper asked you, “Did your bees get a good crop of water this year?” I will hazard a guess that the answer to that question will be, “I have yet to be asked that management question.”

In bee colony management circles, water is much like air. To stay alive, bees must have both water and air. Without both, our bees are dead. There’s seemingly not much else to be written on the subject. Wrong. Water is as important to the bees as it is to the beekeeper.

Even so, water is one of those subjects that never gets its own bee book chapter. The water topic maybe has a few paragraphs in the bee biology section where brood production is discussed. In another chapter, water needs are discussed when instructions are being given about confining colonies on hot days or, in yet another chapter, water issues are a topic for wintering bees when it is thought that hive ventilation is needed.

A COVID moment in my beekeeping

As has everyone else during the past few pandemic years, I have spent more time at home than I would normally have spent. On those quiet days, to keep my bit of remaining sanity, my bees became a significant distraction for me — a few bees in particular.

On one particularly cool mid-December day, when walking by my traditional water source (a bird waterer mounted on a cast iron pedestal), there were about 20 water foragers trying to collect water from the basin. ABJ readers, I need to say that these bees were cold. The temperature at the time was 37°F (2.8°C). Some of the foraging bees were actually frosted over.

This observation undermined everything I had been taught about bees and cold weather. In the perfect bee textbook world, bees begin to cluster at 57°F (About 14°C). For the record, that fact is seemingly true. Bees do seem to begin forming a cluster near that temperature — except for these few foraging bees that were bonkers for cold water. They were ignoring all the textbook information. I asked myself, “How critical could that tiny bit of collected water be to the wintering cluster back in the warm colony? These bees, nearly suicidal, could only be collecting a few drops of water on such cold days.” I could not answer my own question.

The next day was worse. The surface of the water was slightly frozen and some bees had overshot the landing and were in the drink. They were in serious trouble. A few of the floating bees had a thin ring of liquid water surrounding them and I realized, “They are still alive.” Of course, I saved these cold-coma bees, warmed them up and sent them on their way. I would like to believe they got back to the colony and lived happily ever after.

That, readers, was one of my many Covid moments. This particular moment made me realize that I did not understand enough about water needs in the beehive — wintering or otherwise. That episode started me on this theme.

Generalized colony water needs

The commonly accepted reasons bees collect water are: (1) to cool the hive when needed, and (2) to dilute honey for food consumption. Without authority or scientific citations, I offer a third colony need and that is, (3) humidity manipulation of the brood nest. Can any of you think of any other reasons a colony would want water? Otherwise, I am staying with these three water needs that a colony may routinely experience.

Some characteristics of water fetchers

Our present best guesses are that only about one percent of colony foragers are water collectors. Within that one percent, a few make it a fulltime occupation and never collect anything else. With only a foggy understanding of how they do it, water foragers search the surrounding neighborhood for both temporary and permanent water sources. Selected sites may be as small as a few ounces of water dripping from a leaking faucet, or as large as a lake. For water supply dependability, at any given time colony water foragers must know the locations of multiple water sites.

Disconcertingly, those sites may not be pristine by human water consumption standards. Indeed, foragers seem to prefer sites with algal growth, or cloudy water garnered from standing water pools. Maybe such questionable sources have a distinctive odor (or taste), or maybe such water better meets nutritional needs back in the nest. I don’t know.

Probably inspired by assertive house bees quickly unloading water loads from returning water foragers, water collectors dedicatedly begin to make repetitive trips to their respective sites to ferry water. The house bees are in need of water for diluting honey, liquefying crystallized sugar, or for lowering the heat within the brood nest area. They are frantic to have their needs met.

It should be noted that some scientific observers report that nectar foraging continues, even at times when water foraging has priority. When, and if, and how quickly nectar collectors convert to water collecting activities is unclear. It is not uncommon to see water foragers with their Nasanov glands exposed at the water site. This would obviously be to aid novice foragers in finding the source.

Depending on colony needs, water carriers can make as many as fifty trips per day and seem to prefer water sources that are near the colony. It only takes a minute or two for the bees to siphon their water cargo. Water foragers have been reported to bring in seven to thirty-two ounces (207-946 ml) of water per colony per day. Water is not stored within the colony combs but rather is puddled on combs, or alternatively, bees may evaporate water on their tongues. (I write this because others report it, but in my personal experience, I have never personally seen either of these events. But that doesn’t mean that it does not happen.)

When is it plain water and when is water simply a diluent?

At specific junctures, this whole water-collecting thing really gets muddled. When are bees collecting water and when are bees collecting salts and/or minerals that some water suspends? On occasion, are they collecting both at once?

Earlier, I described my astonishment at bees’ water-foraging activity on frigid days, and now I admit my puzzlement at bees foraging on damp compost or imbibing the blue fertilizer water coming from the drain holes of potted pine tree seedlings. I have even seen bees collecting brine that had puddled at the base of cattle salt blocks. Are these bees collecting water or are they collecting mineral salts? Recall from above that I wrote, “Our present best guesses are that only about one percent of colony foragers are water collectors.” It could be that maybe one percent of that one percent (one in ten thousand foragers) have a significant taste for high concentrations of salt and are the “super salt” collectors. I suppose that such a conclusion is logical. We know that foragers have varying sensitivities to nectar sugar levels, but that may or may not apply to bees’ collection of mineral and salt-laden water.

Specifically providing salt water for our colonies seems to be an “iffy” recommendation. The old bee books took salt foraging and feeding more seriously. As early as 1870, A.I. Root in his book “ABC of Bee Culture” wrote, “At times, bees unquestionably show fondness for salt water, and I presume they should have access to salt in some way, as well as others of the animal kingdom. … They seem to have a preference for it in a much diluted form, and are very often seen eagerly hovering over barrels containing refuse brine.”1

If you can find a modern-day recommendation for feeding salt to bees, about a tablespoon (7.8 g) of salt per gallon of water has been suggested. In verbal communications with a beekeeper of long ago, I was told to add a “dash” of salt to my gallon of sugar syrup and bees would take it more readily. If it worked for sugar syrup, may I assume that it would enhance plain water? Or possibly, was the old beekeeper just wrong? In any regard, if you opt for feeding salt to your colony, a little bit seems to go a long way.

An oddly dangerous colony task

You and I have already discussed immobile water foragers dunked into frigid water, but bees in the water can happen in warm parts of the season, too. Yes, I know, put floats in the water. I do, but some bees still manage to drown. At times, I have wondered if the forgers just happen to die at that site. “It was just their time.” I struggle to say water foraging is riskier than nectar and pollen collecting. How about colony defense? That’s risky. I suppose most colony tasks have an inherent danger factor, but why do so many bees seem to miss the landing? Does clear water have come kind of polarized reflection that affects the bees as they approach the water? Maybe clear water is simply hard for alighting bees to see. Was it a late wind gust that pushed them into the water? Regardless, I can say that bees, while adroit fliers, are not great swimmers. They are completely unable to direct their swimming motion. They try to “fly” when in the water in whatever direction their dire situation takes them. While swimming in circles is better than not trying at all, their water behavior is simply not great. Drowned bees have a soaked look about them that still-living bees do not have. Obviously, bees beneath the water are finished.

About those drowned bees

Okay, we have multiples of bees at the water’s edge taking on a load. As it were, they are all sharing the same glass. Maybe there are five to ten drowned bees in the gallon of water in my bird waterer. Does that water become a source of pathological contamination? One single time, only once, I saw a varroa mite on a bee at …