What do Bees do with Water?

Cooling and Consumption in the Colony

On hot days, worker bees will collect water to spread throughout the hive. The bees fan their wings to evaporate this water and cool the colony. This is one use of the water, Bees however, use water for many other purposes, as in humidity & temperature control (both the individual bee and colony), digestion and larval care (i.e. production of bee bread and royal jelly).

There’s a shirt that goes with this article, designed & printed by yours truly:

Where do Bees get Water?

When living in the natural beehive, bees source water from ponds, lakes, rivers and streams (slow-moving or calm sections, of course). On cool mornings, bees can collect water from the dewdrops on plants and grass. Bees have also been shown to utilise what we could consider “dirty” water: muddy puddles and animal urine (Abrol et al., 2012).

What these locations share in common over man-made sources are the higher concentrations of dissolved minerals. Animal wastes contain salts (sodium, potassium, chloride, magnesium and calcium), as well as other organic molecules and minerals. The ingestion of water from these sources fulfils the needs of the individual bee and hive, making them an ideal water source. If however this water was gathered for the purposes of colony cooling, then the micronutrient concentrations do not matter and bees will collect from whatever source is safe and accessible.

This water preference is seasonal. When pollen was scarce during the autumn months, water containing calcium, magnesium, and potassium was prioritized. When pollen is abundant, as in the late spring and summer, these water sources were instead avoided. This study by Bonoan and colleagues (2016) showed that honey bees forage for minerals in “dirty” water based on what is lacking in their floral diet during the season.

A birdbath is the most common man-made water source. Bees will either drink from the edges or stones/twigs that protrude above the water where they can land and drink without the risk of drowning, as in the image above. Some beekeepers like yours truly have seen bees drinking from the slow drips of a leaky hose or garden faucet. For those urban beekeepers, you may see them attracted to the chlorinated water in pools¹,

Water Requirements of Solitary vs Social Bee Species

Solitary bees do not have a colony to support, so their water needs are for personal consumption and nest provisioning. Altered water availability does not impact solitary species directly, however this would reduce floral availability and thus available nutrition (Rankin et al., 2020). For those interested in helping native bees, providing water and nesting sources from the local landscape is one way to get started.

Social species like Apis mellifera need water to hydrate the entire colony, which consist of tens of thousands of individuals. Its hive cooling roles are stated above, and water is also required to maintain the right humidity levels.

The ideal humidity in social colonies fluctuates depending on the area within the hive (Human et al., 2006). In African bees (Apis mellifera Scutellata) the brood area had a higher absolute humidity (a measure of the actual amount of moisture in the air, regardless of air temperature) compared to the nectar-ripening regions. The authors suggest that worker bees choose to evaporate water in this region of the hive to keep the high humidity required for brood development².

In this study, A. mellifera Scutellata colonies had a lower absolute humidity in the nectar ripening region, despite the constant evaporation of water from the compound (the water content of nectar from the spotted aloe, Aloe greatheadii var davyana is reported at 77%). This decrease in humidity enables a faster evaporation of nectar into honey and is also a preventive measure against microbial growth, reducing the risk of spoilage after cell capping.

What Bees do with Sugar Water

Sugar water (“sugar syrup”) is offered by beekeepers as a form of honey bee supplemental nutrition during shortages of natural nectar sources (dearth). Bees either consume the syrup as an immediate source of energy. or bring it back to the hive, where it’s processed and stored in the wax comb. The liquid is fanned, and this syrup is either dried into “honey” or mixed with pollen to make bee bread for the bees, not just the larvae (“brood food” and “royal jelly” are misnomers, the entire colony consumes them, not just the brood – see Crailsheim 1992).

The term “honey” is questionable. Sugar syrup lacks the nutritional complexity and beneficial compounds found in natural nectar-derived honey. When used in large amounts and beyond necessity (i.e. to keep bees from starving), a beekeeper can no longer call his stock of honey “organic”.

Sugar Water is Necessary if Honey is Harvested in Autumn

The common sugar feeding time is in autumn. Beekeepers will harvest the last batch of honey (and keep several frames for the bees if they’re generous), and let the colony subsist on the sugar water. If temperatures get too cold, the bees will not feed on the sugar syrup on account of its water content. In this case, a thicker feed (2 parts sugar to 1 part water) or slightly-moist, fondue-like powdered sugar granules are used instead. Too much water is too much humidity and temperature-cooling effects; counterintuitive to the colony’s goals on warming the hive.

Sugar Water in Spring Feeding and Swarm Settling

Feeding sugar syrup in the early spring (in 1:1 mixture) stimulates hive activity, enabling the colony to ramp up brood production. Beekeepers do this to encourage colony growth after winter, especially for hives used in commercial pollination operations, who require large amounts of foragers in periods when flowering plants are slowly blooming.

For example, the almond Prunus dulcis is one of the first flowering spring crops, occurring before the tree produces leaves. This early flowering benefits the commercial operation, as there are fewer flowers to bees away from the almond tree. Once the bloom ends (around a month), other plants would have flowered and so the beekeeper can return the hives back to their usual location (or more likely, onto the next crop).

If a colony is stressed after relocation, or if a swarm is captured, sugar syrup can be provided to help the bees recover and regain their energy. Outside of swarming, the migration of bees in A. mellifera colonies is unnatural, but in other honey bee species like the giant honey bees Apis dorsata, this is common. Modern problems require modern solutions, and the sugar syrup is a sweet solution (double-pun intended).

Sugar Water for Medication Delivery

Speaking of modern solutions, beekeepers use syrup to medicate colonies. The bees are attracted to the sugary water, and consume the drugs alongside it. Syrup drug delivery has been used in:

• Fumagillin, an antifungal for treatment of Nosema disease.
• Oxalic acid, a chemical control of Varroa mites (Gregorc & Planinc, 2002)
• Tylosin, an antibotic treatment of American Foulbrood (although new formulations utilize powdered sugar instead, e.g. Powell et al., 2021)

What do Bees do in Hot Weather?

In hot weather, bees maintain optimal hive temperatures and humidity for brood rearing and proper wax comb structure. Worker bees will position themselves at the hive entrance and inside to fan their wings. This circulates air throughout the hive, cooling it and aiding in the evaporation of moisture (formed due to excessive water collection by foragers, or the nectar ripening process).

The contents of the honey bee stomach from returning foragers hold water rather than nectar, for plants do not produce much nectar in hot conditions (ranges vary, with daytime temperatures of 35°C being the cut-off for most plants; Jakobsen & Kritjannson, 1994). The water is spread around and the fanning bees evaporate it, cooling the hive.

Bearding is when a large number of bees gather around the hive entrance. This behavior reduces the internal temperature of the hive by decreasing the number of bodies bees inside, lowering the collective heat they would have otherwise produced.

These actions aim to maintain a constant 35°C for brood development. In extreme heat, bees may abscond a hive in search of a cooler, shadier locations. For beekeepers homing hives in an exposed or hotter environment, consider applying shadecloth during the summer months.

Plants, Pollen & Nectar in Hot Weather

A sidenote: generally, high temperatures are correlated with water scarcity (a mini-drought if you will) and reduce the availibity of nectar and pollen. Nectar can evaporate in extreme heat and plants have developed specific adaptions based on their environments. In borage plants (Borago officinalis), a 6°C increase in daily temperature resulted in a 60% decrease in the total quantity of nectar produced, and 65% decrease in pollen weight per flower (Descamps et al., 2021)

Suni & colleagues (2020) found that plants from drier environments (in this case, the Texan-native annual pholox Phlox drummondii) produced more nectar with higher sugar content as a result of water-stressed conditions… its quite interesting considering that nectar is predominantly composed of water and sugar, both of which would be limited in dry conditions. Perhaps it’s a reproductive adaption that ensure the pollinator visits the plant in order to carry its pollen and therefore spread its spores elsewhere?

In contrast the same pholox plants grown in wetter environments (“eastern distribution” in this study) produced less nectar with a lower sugar content under water stress. Under drought-like conditions, both plant phenotypes had overall reductions in their flower size and number. This reduction was greater in those grown in wetter-environments compared to dry ones.

A systemic review by Schramm and colleagues (2021) found that (airborne) pollen production increased at higher temperatures. Optimum conditions for pollen release are temperatures of 20°C and above (but if it becomes too hot and too dry, the flowers wither). For bees and other foraging insects, plant adaptations to high temperatures influences their foraging behaviors. A variety of response to heat exist:

• Some plants open their flowers early in the morning or late in the afternoon to avoid the peak heat.
• Others might close their flowers during the hottest parts of the day to conserve moisture and protect their reproductive tissues.
• Some plants change the orientation of their flowers to minimize direct exposure to sunlight.

How Beekeepers can Provide Water for their Bees

Beekeepers should ensure that their colonies have access to a clean and consistent water source during the hot and/or dry periods. If natural sources are not available, providing an artificial alternative like a bee bath (with sticks or pebbles for bees to land on) gets the job done.

Bees are wild animals and cannot be forced to do something. Even if water is nearby, the foragers may choose another area. It is why knowledge of scientific beekeeping principles greatly aid the backyard beekeeper in better manging their bees and backyard.

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Footnotes

1. This is not an ideal source for them on account of the other chemical products used in pool maintenance. Also, neighbours would not take kindly to bees in their pool. They’ll either panic, get stung or both. Many such cases! ↩︎
2. A high humidity also prolongs the hatching time of small hive beetle eggs. ↩︎