As you will know, your bees live on nectar taken from plants, which they turn this into honey. Dearth is the word used to describe those times of the year when nectar is not available for the bees.
Dearth means scarcity and is particularly used when food is in short supply.
How The Colony Works
Bees are natural foragers and resourceful at finding food. This means they will not starve if any food is available.
In their life cycle, worker bees perform different roles. In the winter they are born in much smaller numbers and live longer. Conversely, in the spring, they are born in larger numbers and have shorter lives.
They start out by staying inside the hive performing tasks including cleaning the comb, gluing the hive together, and making honey from nectar brought in by foraging worker bees.
After about 10 days most bees become foragers, leaving the hive to find the raw ingredients for the colony’s survival. These bees collect four things: nectar, pollen, propolis, and water.
Propolis is collected from the buds of plants and is used to glue the hive together; pollen is collected from flowers and provides various proteins and vitamins; water is collected as needed.
The Rhythm of the Hive
But bees will always collect nectar to make into honey. If it is out there, they will go after it.
If you watch your bees, you will see pollen and propolis coming in attached to the legs of the foraging bees. But nectar is stored inside the bees in the honey stomach, which is designed to transport it back to the hive. Once in the hive, the worker bee passes this nectar to other worker bees, which, through various processes, will turn it into honey and store it in a honeycomb.
A worker bee in the summer lives for about 26 days. After 10 as a house bee, this bee becomes a forager. This process is driven by changes in the internal organs to make it more effective at the different tasks that the colony requires for its success.
Nectar is principally a suspension of sugar in water, and different plants produce nectar with higher and lower concentrations. Even the same plant can have different sugar content for nectar depending on whether it came from the sunny side (greater) or shady side (lesser).
When the foraging bee returns to the hive, it has to wait for the house bee to unload the nectar from its honey stomach. When a bee returns to the hive, the house bees choose to unload honey with a higher sugar content first. As a result, the bees learn to prioritize collecting nectar from the best sources first.
The physiology of the bee is important also in that it helps to regulate what happens inside the hive. In the winter, worker bees live for around six months and are not expected to forage because there is simply nothing to forage for.
While you could describe the winter months as a dearth period, one of the reasons why colonies build up honey supplies is so that they have plenty of stores to survive this period. For a beekeeper, dearth is more of a concern when the bees are expecting to be collecting nectar.
Things to Watch Out For
Therefore, colonies can die of starvation in winter or summer. But summer is a more acute period of risk for the beekeeper. Think of it this way: the natural population of the hive grows sharply in the spring. This is so that the bees can collect as much nectar as possible. If the nectar tap is switched off, then the colony is full of bees that are designed to live in a time of abundance, and they are not able to cope.
The plants that are available to the bees in the land around the hives, be it urban or countryside, will set the expectations for the colony about how big to grow. While farmers may play a crucial role in this by changing the crops that they sow, bees generally find the nectar that they want. Beekeepers should be used to observing what pollen is being carried in by their bees.
The beekeeper also needs to pay attention to the weather. When it is cold, nectar production reduces. Plants either secrete less nectar or stop altogether. Heavy rainfall is another hazard as this can wash all the nectar out of a plant.
One major risk is if the plant life around the hive consists mainly of spring flowering plants and autumn flowering plants, with no flowers in the summer.
Successful beekeepers need to know something about botany. You need to find out what plants provide good nectar and to be aware of where they grow locally. By being aware of what is growing and whether it is flowering early or late will provide you with an early warning of what may be happening in the hives.
When nectar is widely available, you will probably not see your bees because they are flying fast and high and all day. So a warning sign could be that you notice bees clustering near the entrance to the hive (like they do when preparing to swarm).
You may also notice that they are bringing in pollen from plants that are lower down the pecking order in terms of nectar quality.
Or they are flying lower.
Or that the hive sounds different.
Another sign of problems is when you see bees from a stronger colony trying to get into a weaker colony to rob its stores. This is especially a problem because it can cause cross-contamination of colonies.
For the newcomer, this is always quite confusing because observing bees closely provides you with multiple things to worry about. The more experienced beekeeper develops a sense of what is going on in his/her hives, in part from worries overcome.
As with many aspects of beekeeping, you need to think about the whole environment around the bees before acting.
Actions to Take in Case of Dearth
If you have starving bees, you can feed them by making a syrup. The ingredients are simple: white granulated sugar mixed with warm tap water.
As a guide, you should expect to be half-filling a container with warm water and then stirring in the sugar until the container is full.
The syrup is put into a specially designed feeder and given to the bees. Many beekeepers prefer to use feeders that sit inside the hive rather than by the entrance. This is because an external feeder may attract other colonies and encourage robbing.
Another thing to do to prevent robbing is to reduce the size of the entrance. This will make it harder for robbers to enter. Also, check the supers for signs of holes. If you find them, cover then with tape for now.
If you are a gardener, one thing to consider is to stock your beds or containers with summer-flowering plants that will provide plenty of food for your bees. What you may lose with less attractive displays in the spring and autumn you will make up with happier bees.