Bees and water: the ladies drink for free

Who doesn’t love watching a honey bee drink, its complex tongue exploring the surface of a leaf or wet rock? Beekeepers the world over have designed watering holes where bees can belly up for afternoon refreshment. Some of these devices are small and unobtrusive, while others are works of art, astounding in their originality.

Life on Earth depends on water. Even marginal life forms like viruses need water, something they can hijack from a host cell. When you examine the physical and chemical properties of water, you can see why it became the centerpiece of life. Water is perfectly structured for dissolving many chemicals, thus enabling a fantastic number of reactions to occur. And in its liquid form, water can easily channel the newly formed molecules wherever they need to go.

Although we have no trouble remembering to provide water for our pets and livestock, something about insects makes us forget. At least temporarily. Water may never enter our beekeeper minds until the neighbors complain about bees in their dog dish, swimming pool, or on the hose bibb they just grabbed with memorable results.

How honey bees use water

An individual insect doesn’t need much water, but a colony of six leggers requires a substantial amount. And when that colony uses water for purposes other than direct consumption, the volume can be mindboggling. A fully functioning honey bee colony has an extraordinary water demand. The usage varies with seasonal activities, population levels, air temperature, and humidity.

A continuous supply is needed for basic life functions such as digestion, circulation, distribution of nutrients, waste removal, thermoregulation, and internal homeostasis. In addition, a colony uses water for raising its young and maintaining a livable space. For example, bees use water to dilute honey or sugar so it can be easily consumed by larval bees. Nurse bees that are actively producing royal jelly need water to keep their glandular secretions flowing. Water also keeps the brood nest humid enough to prevent larval desiccation and cool enough to prevent bee death and comb slumping.

Water demand in bee colonies

The actual amount of water used by individuals or by an entire colony is difficult to calculate because of all the variables. For example, nectar is a primary source of water, but the amount of water varies with the source. Nectars with high sugar content provide less water than low-sugar nectars, but low-sugar nectars are collected less frequently.

Honey bees can absorb some water from nectar while they carry and process it, but how much is difficult to say. Because it is so onerous to measure, water from nectar is generally not calculated into usage estimates.

Another confusing aspect is water usage in overwintering colonies. Honey bees often recycle water by consuming condensate within the hive. Part of this accumulation may come from outside air, part is from honey bee respiration, and part may be from liquid feed or honey. Even rain and snow, leaking through cracks and openings, can add to the supply.

Despite the difficulties, some researchers have calculated estimates of usage. One popular paper estimates a normal colony will need about 44 pounds per year — about 5.3 gallons — added to whatever the bees extract from nectar.¹

When enough is enough

House bees regulate how much water foragers bring in. If a house bee refuses to unload a water carrier — or does it too slowly — the water carrier will cease collecting. On the other hand, if the water is offloaded quickly, the forager will fetch another load. It’s a simple matter of supply and demand: Lots of supply means little demand and vice versa.²

The water carriers usually disperse their payload to many house bees. Part of the water may be absorbed by thirsty workers or shared as necessary. If the hive interior becomes too hot, workers spread water on capped cells or on the edges of open cells where it can be used to cool the hive.

Evaporative cooling

The amount of cooling needed inside a hive will vary drastically with the climate, the size of the colony, and the amount of sun exposure. However, experiments have shown that honey bees are magicians at maintaining proper hive temperatures as long as they have a steady source of water for evaporative cooling.

Swamp coolers and air conditioners use the principle of evaporative cooling, but honey bees had it nailed long before the idea ever crossed a human mind. For a quick refresher on what evaporative cooling is, just imagine yourself stepping out of a warm shower into a cold room. Brrr! Even if the bathroom is warm according to the thermometer, you can feel your teeth chattering in a matter of seconds.³

Water molecules jiggle faster as they get warmer. The molecules in a cube of ice are virtually locked in place, while those in water move around freely, but those in water vapor dance and gyrate like crazy. Heat is the motivator, the energy that makes the molecules shimmy.

In a drop of water, the molecules with sufficient heat are the ones that escape into the atmosphere and become vapor — the stuff that fogs your bathroom mirror. So when you expose your wet body to the air, the warmest molecules decamp first. But when they leave, they take their heat with them, meaning the average temperature of the remaining water plummets, making you shiver.

Now your body is warmer than your skin. In order to reach equilibrium, heat leaves your body and moves into the cold droplets, a loss that makes you feel even colder. So what do you do? Between shudders, you grab a towel and pat yourself dry. With no more drops to evaporate, you soon feel normal again. The entire process is very cool indeed.

Cooling in the hive

To cool the hive interior, the bees spread water on the combs or attach droplets of water to the frames. Then they fan. The fanning speeds evaporation, and since evaporation carries away the hottest molecules first, the entire hive gets cooler. The fanning also increases the humidity, necessary to keep the larvae hydrated. When the water is gone, the bees add more and continue the process.

In “emergency” conditions, when high temperatures threatened to melt the combs or kill the brood, worker bees will unload water carriers before nectar or pollen carriers. Honey bees are skilled at cooling, so colonies placed in super-heated environments can reliably keep their hives cool as long as they have a constant supply of water.

However, trouble can occur when bees run short. Truckloads of bees exposed to drying highway air or queens enclosed in shipping cages can easily run dry. Whenever you transport bees, providing water is job one.

How do honey bees find water?

Although honey bee eyesight is extraordinary for finding flowers, navigating long distances, and evading predators, it is less effective for finding water. Recent research shows that foraging honey bees respond more to the contrast between colors rather than the colors themselves. According to Adrian Horridge, a specialist in insect vision, “Bees locate and measure amounts of blue in areas and, separately, quantities of green contrast at edges, and the angle between them.”⁴

Since water sources can be any color based on what’s beneath them, and because they often lack contrasting edges, visually searching for water is likely not effective for bees. Instead, they use their sense of smell. Odor receptors, especially those in the feet and antennae, sample the environment for something to drink.

Often, a bee’s choice of water is unappealing to us. The rim of a wet flower pot, a spongy area in the lawn, a drip irrigation emitter, or a splatter of dog pee work just fine. A bee’s affinity for water with “stuff” in it is likely because of the scent of the stuff. The odoriferous infusion is what the bees detect and what attracts them to the source.

As the natural world would have it, the soup the bees select often contains minerals they need in their diets, such as phosphorous, potassium, and salt. These and other micronutrients may be lacking from the various pollen and nectar sources they are using. In a way, a slurp of dirty water is like chasing a vitamin pill with a sip of tea: All your missing nutrients slide down the hatch without swallowing a single Brussels sprout.

Sipping algae through a straw

Nothing, it seems, attracts honey bees like the aroma of algae. Although algae-laden water isn’t something humans prefer, when you examine the places bees like to slurp, you can usually find algae in the mix.

Around my home, bees like the seepage that leaks out of forest slopes. The water gathers in rivulets that draw lazy zigzags across the logging roads, wetting the dust. Where it intersects with sunshine, small tendrils of green slime wave in the meandering water or grow in mossy layers on the semi-submerged stones. This warm chartreuse beverage is the honey bees’ cocktail of choice. They simply insert their own built-in straw.

Slimy layers thrive on the aforementioned hose bibbs, birdbaths, and flower pots. They also show up in koi ponds, pet dishes, water troughs, rain gutters, splash blocks, and compost piles. The water in these attractive beverage bars might be impossible for a fast-flying bee to see, but their keen sense of smell makes up for any deficit of vision.

Scent as a signal

Researchers have found that honey bees in desert areas often mark their watering holes with Nasonov pheromone, a tool that is not normally used for flagging caches of pollen, nectar, or resin.⁵ Since desert environments don’t support many algae, honey bees may use the Nasonov pheromone to help their sister bees find a rewarding water source.

Other scents that seem to attract honey bees to water include chlorine and salt. Both chlorinated and salted pool water are great honey bee attractants, preferences that are probably learned by association. Once a bee finds a swimming pool, she can recruit other water foragers to the source by sharing a scented sample. Many beekeepers report that once honey bees become attuned to the odor of chlorine, they will even sip from bleached laundry hanging on a clothesline.

Saltwater pools are especially attractive. Although we like to pretend that salt is the enemy, all animals need salt to survive. Don’t be afraid to add a pinch of salt to your water source, especially if salt is not abundant in your landscape. Some beekeepers like to use mineral salts that are sold in the pet store as “bunny wheels.” You can crush them with a hammer and add a bit to your water source. Just a tad can add a variety of minerals to a bee’s diet.⁶

First the water, then the bees

For beekeepers living in an urban or suburban environment, providing a water supply for bees should be a priority. Ideally, a system should be in place before your first bees arrive. The reason is simple: Your neighborhood is likely filled with various wet, slimy things, and at least one owner of a pool, dog dish, or flower pot won’t want to share it with bees.

Unfortunately, the time gap between establishing a hive and the first neighbor complaint can be costly. Why? Because once honey bees have selected a convenient watering hole, changing their minds can be tricky — or downright impossible. Reasoning with even one honey bee can frustrate the best of us, let alone a whole colony. It is much easier to provide water right from the git-go than to attempt wholesale retraining.

The water carriers

Water-carrying bees make many trips per day, so a source that is convenient will maximize efficiency. Although dozens of how-to books recommend a “clean source of fresh water,” your bees may ignore such a thing. Most favor water that smells green or industrial.

To keep your bees from searching for water, design a source close to home. Lots of people use entrance feeders filled with water. That’s a great place to start because it’s convenient for the colony. If it runs dry, though, they will soon be on the lookout for alternatives. Other beekeepers like to set up drip systems that allow water to leak into a nearby garden area. Some like to set out containers with pebbles, marbles, corks, or floating sticks that give the bees a safe place to sit while they drink.

Any of these systems will work as long as you provide them before your bees develop bad habits. As with many other aspects of beekeeping, it doesn’t take much time to set up a watering station, but timing is everything.

Pull a switcheroo

If you screw up on this point, here are some tricks that sometimes work on some bees. Short of draining your neighbor’s pool or moving to Timbuktu, there is no sure-fire cure for misbehaving bees. Nevertheless, here are some ideas that may be worth a try:

• Set out stone-filled pans of water laced with sugar and essential oil. Just a drop of an oil such as anise or tea tree will help the bees find your water source and the sugar will keep them interested. If they fancy your alternative source, remove both the sugar and the oil after a few days.

• Instead of sugar and water, some beekeepers like to use salted or chlorinated water, similar to what the bees are accustomed to.

• Set out flower pots full of wet potting soil. Something about the earthy odor of fresh potting soil drives them to drink.

• Wet concrete, both set and unset, is highly attractive to bees, perhaps because of the various minerals. Plain wet sand is also a favorite.

• Plant a nearby garden of lamb’s ear. Not only do honey bees like the flowers, but the hairy leaves hold a treasure trove of water that is easy to forage and stays wet for hours.

The epitome of watering devices

Years ago, I visited a watering device at the Oak Creek Center for Urban Horticulture in Corvallis, Oregon. I fell in love with it. It is huge because it serves a large agricultural area, but a smaller version would be fun to build just about anywhere:

• Water flows into the system from a drip irrigation line. A hose runs up the side of the structure and into a fat bamboo cane that stretches across the width. Holes fitted with drip emitters appear at regular intervals along the length of bamboo.

• The water seeps from the emitters and drips from the bamboo into a trough filled with living moss.

• Overflow from the moss drips down the sides of the stacked rocks, which remain wet throughout the summer. A bed of rocks on the ground beneath the structure drains the excess water.

When I visited this structure, bees were all over it — honey bees and dozens of other species as well. But the bees were not alone. Flies, wasps, butterflies, and things I can’t name mingled with the bees.

The different species congregated in their favorite areas. Some liked the moss, some chose the stacked rocks, and some liked the ground beneath. A phalanx of honey bees waited at the emitters, making them first in line.

I didn’t want to leave this structure. The collection of insect life was spellbinding and protean, changing with the sunlight, the nectar flow, and the temperature. The water feature I envision building will be similar but smaller, about four feet tall and two feet wide. Maybe, if I ever get around to it.

You can have fun watching bees drink regardless of the watering hole you build. But give it a try. They are fun to watch and you are bound to learn something in the process.

Rusty Burlew
Honey Bee Suite

Notes and References

1. Herbert Jr EW and Hill DA. 2015. “Honey Bee Nutrition” in JM Graham (Ed) The Hive and the Honey Bee (p 252). Hamilton, IL: Dadant & Sons, Inc.

2. Childs C. 2020. The Way to Water. 2 Million Blossoms 1:1 pp 8-12.

3. I made the mistake of asking my resident engineer how an air conditioner works. Now my desk labors beneath diagrams of condenser coils, evaporators, compressors, atomized liquids, and equations sprinkled with Qs. I decided it was an act of kindness to spare you the details and stick with cold showers.

4. Horridge A. 2018. Bee Vision is Totally Different. American Bee Journal 158:1 pp.65-67.

5. Winston ML 1987. The Biology of the Honey Bee (p 132-133)

6. Each time I see bees drinking from a swimming pool, I wonder if pool paint is related to pool popularity. Considering how attractive blue is to bees, perhaps both vision and smell play a part in attracting honey bees.