Updated on December 18th, 2020
Nectar is the sugary, sweet liquid produced by plants. Bees use nectar to make honey. It is also a primary food source for honey bees (along with pollen and honey) as the sugar in nectar provides carbohydrates. A nectar dearth is any time that plants slow down or completely stop nectar production.
While winter is the most apparent dearth period, the hot and dry mid-summer (after spring’s burst of flowers and before fall plants kick in) is a typical time for nectar to become scarce.
A dearth is a stressful time for your bees. By mid-summer, your hive population will have increased dramatically. Without new nectar sources, the colony places increased demand on its existing stores.
A lack of adequate food can weaken the colony. Brood production can drop. Population decline means fewer bees foraging when the fall nectar flow comes. Fall honey production may not be adequate to get the colony through winter. And the honey they do have can be robbed by other bees and wasps.
This domino effect endangers the survival of your hive.
As a new beekeeper, learn to recognize the signs of a nectar dearth and how to deal with it.
Recognizing A Nectar Dearth
Look for signs that the nectar has stopped flowing and you’ll be ready to help your colony get through it. Pay attention to the following indicators.
Lack of Flowers/Rainfall
Pay attention to your environment. You’ll eventually get to know when different plants bloom and die off.
Grass starts to turn brown.
Plants in a vegetable garden stop producing new flowers and begin to set fruit.
In our area, this usually coincides with periods of high heat and less rainfall. July and August are when we need to pay close attention to the signs of nectar scarcity.
See our article 11 Best Plants For Honey Bees (And 5 To Avoid) for information on plants that help feed your bees during the year.
When nectar is scarce, robber bees (along with bumblebees, wasps, yellow jackets, and others) will attempt to take advantage of weak hives and rob their food stores. One of your own colonies might steal from another.
For a newbie, robbing might look a lot like foraging bees just returning to the hive or young bees orienting themselves. Bees with pollen baskets are not robbers.
When bees are robbing, you’ll see frenzied activity around the entrance.
The colony under attack will aggressively defend itself. You’ll see bees fighting and maybe even being dragged out of the hive. You may see an unusual number of dead bees around the entrance.
Look for other types of bees or wasps trying to gain entry. I’ve seen large bumblebees go into a hive only to be driven back by several of my honey bees. (You go, girls!)
Robbers often search around the sides and back of the hive, probing any crack for a possible entrance. The bees from the hive don’t do this because they know where the openings are.
Weak hives can be destroyed by robbing. Bees, including the queen, can be killed. Honey stores can be depleted entirely.
If you see robbing, take immediate steps to minimize it. Better still is spotting the dearth before the robbing so you can prep the hive before it happens.
See More About Robbing below.
Maybe aggressive behavior is the wrong term. I prefer to think of it as a more defensive behavior.
With nectar scarce and pressure on its food stores increasing, your bees may become a bit more challenging to be around. Your presence is no different than that of a robber bee. You are a perceived threat. (Don’t take it personally.)
There may be other reasons for this change in temperament. But in the heat of summer, dearth is a likely cause.
Buzzing and Bearding
During a dearth, your bees may be louder than usual. Since nectar dearth tends to coincide with high temperatures they may beard and fan on the outside of the hive trying to cool down.
Without much food to forage, they may just hang around the hive rather than head off on a fruitless search for nectar.
Bees In Unusual Places
During strong nectar flow, I love to stand by the apiary and watch the bees shoot out of the hive headed off to forage. They go off in all directions with a sense of purpose. If the light is right, I can follow them as they fly over treetops off into the distance.
At those times, we seldom see our bees on our back deck. During a nectar shortage (or drought) they are commonplace on our deck looking for food and/or water.
Bees will also be attracted to other foods they might normally leave alone. You may find them checking out your hamburgers, soda or beer.
Bees may be flying low, in the grass, looking for food. You may see them visiting your hummingbird feeders.
No Nectar In The Comb
While inspecting a hive, you may see that the bees have used up most if not all of their nectar stores. No nectar in the comb is a sure sign that they’ve stopped finding any new sources.
No New Eggs Or Larva
A lack of eggs or larva could be a sign that your queen is gone or not producing well.
However, during a nectar dearth, the queen may be moderating her behavior to conserve energy and food stores. Also, the bees may be eating larva for their protein.
No New Wax Or Damaged Comb
Bees will only draw comb if they have a use for it. If the queen has quit laying, the bees are consuming existing stores and nectar has stopped flowing, there is no need for new comb.
Frames may sit empty while the bees wait for nectar to become abundant again.
Robbers want to steal honey and get out of your hive alive. Unlike the home colony, they will not open capped cells neatly. Look for ragged edges of chewed comb or a lot of wax on the bottom board.
Bees Revisiting Flowers
Bees will typically visit a flower, take what they can and move on. If you see a bee going back to flowers again, it’s a sign of desperation in the pursuit of nectar.
What To Do In A Nectar Dearth
Reduce Or Eliminate Entrances
Help your bees fight robbers. Use the entrance reducer to create the smallest possible entry.
Close off upper entrances. If your hive is strong, give the bees the fewest entry points to defend. If your colony is weak, consider closing it up completely. Using screens will permit the flow of air for ventilation but prevent entry.
A robbing screen might be the best solution for your lower entry. Consider using one as an alternative to an entrance reducer. Check that…don’t just consider it. Get one and use it.
See More About Robbing below for information on robbing screens.
Feed Your Bees
As always, feeding is a judgment call.
Your bees may have plenty of honey and nectar stored to make it through a dearth. However, you need to think about whether they’ll be able to replenish those stores in time for winter. Here in the northeast where winters can be especially hard on the colony, we opt to help out by feeding.
Feeding bees at this time can be good and bad. While your bees will welcome the supply, the scent of the syrup may attract robbers. Try to avoid spilling any syrup on or around the hive which can make matters worse.
Use 1:1 (or thin) sugar syrup. The bees will take this in place of nectar. Knowing when a dearth is likely in your area gives you time to make syrup in advance.
See our article on What, When & How To Feed Bees for information about making syrup and different types of feeders.
Use an enclosed hive top feeder. An entrance feeder only serves to attract robbers to the entrance.
Some beekeepers recommend open feeding. Open feeding involves setting up large, community feeding stations where bees get sugar syrup away from the hive.
We don’t open feed. We think it will only attract other insects and is likely to set off robbing if placed too close to your hives. However, I get the appeal of it for beekeepers with large apiaries and the room to put feeders far from the hives.
Set Up Watering Locations
Our hives are near a wetlands area with a small stream. In the heat of summer, the stream may run dry with a lack of rainfall. In addition to providing sugar syrup, it’s a good idea to set up watering locations.
Just like with feeders, try to set up any watering to minimize the risk of drowning to the bees. You can find lots of creative ways to provide water.
Though we’re not fans of open feeding of sugar syrup, the same method (a large inverted bucket) can be used to provide water. We’ve put out large open buckets of water with wood floats for the bees to land on.
An outdoor faucet set to drip lightly on a board or other hard surface can give the bees a place to hydrate. This year I think we’ll try the “beetainer” we found here using soaker hoses.
Shallow saucers or bird baths filled with marbles or pebbles are great for providing water and landing spots for the bees. Check out this video for an example:
Limit Hive Inspections
Without a reason to forage, your bees are likely staying home. They are more irritable and can be particularly defensive. This is not the best time to be opening the hive and probing around.
Opening the hive during a dearth exposes the stores to robbers. I’ve made the mistake of taking off the covers only to see yellow jackets take advantage of the opportunity to grab some honey
If you must get into the hive to check things out, wait until later in the day when robbers are likely to be heading home before dark.
More About Robbing
I can’t overemphasize the damage robbing can do to a weak hive. Bees exert a lot of energy defending their turf at a time when food supplies are under pressure. A colony unable to adequately protect itself can be cleaned out in a short period.
The best way to deal with robbing is to stop it before it starts. This is easier said than done.
The steps you take to prevent robbing limit access to the hive by outsiders. They also inhibit the smooth movement of your own bees in and out. You want the entrance wide open during strong nectar flow and don’t want to close it up too soon.
If you know a dearth has begun, it may pay to reduce entrances a little early. Ask experienced beekeepers in your area for advice. This is a situation where belonging to a local beekeeping association or having a mentor is helpful.
If your hive’s been wide open so the bees can take advantage of the nectar flow, do you know where your entrance reducers are? Once robbing starts, you need to shut it down quickly. This is not the time to be fumbling around looking for reducers (like I’ve done). Know where your equipment is so you can react quickly.
Robbing screens (also called robbing/moving screens) are simple mesh screens secured in front of the opening of the hive. The screen effectively raises the entrance about 5 inches.
Robbers are attracted to the entrance by the pheromones and scent of honey from the hive. These are most detectable at the bottom of the screen. As the robber moves up the screen, the scent gets weaker, and she doesn’t know how to get in.
Place your robbing screen on in the evening after the foragers returned. You don’t want your own bees confused as to how to enter the box.
The next day your bees will take some time to figure it out as they exit. The screen will force them to re-orient a bit. I’ve watched while they climb the screen checking things out. In about an hour or so they got the hang of it and were able to come and go freely.
According to this interesting article by Dr. Eric C. Mussen at UC Davis, it appears that robbers that have no problem with screens on their home colony still have difficulty bypassing a screen on another hive.
Robbing Screen Options
There are different styles of robbing screens you can try.
Many suppliers sell robbing/moving screens. These are wood or plastic devices that can close entrances entirely keeping the bees inside for relocation. (In a relocation, shutting them in for 2 or 3 days will force them to re-orient to the new placement.)
Always add robbing screens at night after all the foragers are back in the hive. If you put the screen on earlier, returning bees will not be able to figure out how to get back in.
The morning after you add a robbing screen, the colony will figure out how to go up the screen and out. Having done so, they will be able to return properly.
I’ve watched bees adjust to the screen. It seems to take somewhere between 20 and 60 minutes for most of the bees to figure out what’s changed.
Some screens are wide open across the top. Others have limited openings (effectively a reduced entrance).
I’ve seen designs that leave a small opening at the hive entrance and a small opening at the opposite top end. This forces your bees to traverse the screen going in and out and complicates matters for the robber.
Robber screens are easy to make with minimal woodworking skills .Make sure your robbing screen the proper width for your hive: 10, 8 or 5 frames.
Here’s a picture of one we made secured with bungee cords:
What plants produce the most nectar for bees?
Check out Wikipedia’s List of Northern American nectar sources for honey bees for some ideas.
When adding plants to help your bees, keep in mind your hardiness zone. Also, think about a variety of plants with different blooming periods.
What about the winter dearth?
With temperatures too cold for foraging and a lack of flowering plants, bees rely on their stores of honey to get through the winter.
You can help them by:
- leaving them adequate supplies of honey (do not harvest honey the first year)
- feeding them syrup in late fall (watch for robbing again)
- providing sugar as a backup supply of food (it’s too cold for syrup)
- properly winterizing your hive to conserve heat.
Do bees make honey from sugar?
No. Honey is only made from nectar. Nectar contains compounds not found in plain sugar.
Bees can use sugar to build comb. They can also store it in a manner akin to honey. Stored sugar can serve the bees as a food substitute for honey.
If you feed your bees and don’t pay attention, you might end up harvesting “honey” that’s really stored sugar syrup. We tend to feed the bees without honey supers on the hive so that any sugar syrup stored is kept in the brood boxes.
For details on how bees convert nectar into honey, read this article in Bee Culture, The Chemistry of Honey.