Like water for bees

In the midst of summer here in Australia, it’s the perfect time to consider the importance of water for bees, and the value of water in bee nutrition and health.

Honey bees forage for water for two purposes, in addition to individual requirements. One is to use it to dilute honey so that honey can be added to brood food. The second is to use water to cause evaporative cooling by fanning over a thin layer of water when the ambient temperature is over 35 °C.

Honey bees use their proboscis, a thin, straw-like appendage, to take up water. They store the water in their honey stomach, or, crop, in order to safely transport the liquid back to the hive. The proboscis, in this case, serves to facilitate the transfer of water from a water source to the hive, where the worker bees put it to use. 

The house bee will carry the water to the honeycomb, regurgitate it out on the cells, and fan the liquid, which serves to cool the hive via evaporative ‘air-conditioning’.

Honey bees use olfactory cues to find sources of water. They can detect water that has higher levels of salt, chloride, and specific minerals that honey bees seek out.  When bees have a choice, they usually prefer water with some minerals (for example, they’ll often choose a swimming pool). 

The honey bee has a sense of smell, but they don’t have an olfactory structure like a human nose.  Instead, honey bees use their antennae and their front legs to ‘smell’ for different substances, including fragrant flowers as well as the odours given off by water. 

A study found that honey bees were more sensitive to salty and sweet tastes than bitter tastes.  Additionally, bees are even more sensitive to salty tastes than sweet.  The researchers demonstrated this by observing how quickly and how much the proboscis (‘tongue’) of a honey bee would become active when presented with various flavours.

Researchers at Tuft University in the United States investigated if the preference for ‘dirty’ water was adaptive and seasonal. They asked if foraging workers compensate for low availability of essential minerals in flowers by collecting dirty water from different sources depending upon the time of year.

The findings show that honey bees forage for essential minerals that aid their physiological health, even though they have relatively few taste genes. In the autumn, when floral resources decline, the study showed that bees seek out specific nutrients – calcium, magnesium, and potassium, all commonly found in pollen – by foraging in compound-rich or ‘dirty’ water. When flowers and pollen are abundant in the summer, the bees prefer plain water and sodium, ultimately suggesting that bees are foraging for minerals in water based on what is lacking in their floral diet.

Beekeepers and home-owners can provide water to bees during summer with 0.1–0.2% table salt (NaCl, sodium chloride) added.  Use non-iodised salt if possible.  Do this early in the season so that bees will become accustomed to the water source. Provide a floating device or rocks to keep bees from drowning, and replenish the water source as needed. Never let it run dry or bees will find a new water source.  

(image credit: https://commons.wikimedia.org/w/index.php?curid=1992680)