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 allows us to 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 that 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 is hot, water will be spread on capped cells or on the edges of open cells where it can be used to cool the hive.
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 threaten 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 ….