honey bee behavior

What is a summer nectar dearth?

Bees on dahlia Pixabay

Honey bee colonies store nectar and pollen to use in times of dearth. To a honey bee, a dearth is a shortage of nectar-producing flowers. The most obvious nectar dearth occurs during the winter, but many places also experience a summer nectar dearth, a hot and dry period between spring flowers and autumn flowers.

This time of shortage may escape a new beekeeper’s notice because, after all, it is summer and the world is green. Sometimes flowers are clearly visible and it’s easy to assume that if flowers are present, the bees are happy. But not all flowers produce nectar accessible to honey bees. And among those that do, the amount of nectar can be reduced by low rainfall, excessive heat, or other less-than-ideal growing conditions.

A summer dearth can be worse than winter

The summer nectar dearth can be devastating to a honey bee colony. At times, it can destroy a colony faster than a cold winter. Whereas a bee colony has time to prepare for winter by increasing storage and decreasing population, a summer dearth hits when populations are very high. Large numbers of bees—especially active bees—require a lot of food. A large colony can wipe out its warehouse very quickly, and if the beekeeper has already harvested, the problem is worse.

Desperate times call for desperate measures, and a severe summer nectar dearth can cause many types of unwanted behavior. Simply put, idle bees get into trouble.

A dearth causes nectar robbing

One of the most common problems is nectar robbing. Strong colonies will attempt to rob weaker colonies of their nectar stores. Once robbing begins, a colony can be stripped of its food supply, fighting and dying become rampant, and the queen may be killed. Worse, the smell of open honey soon draws other predators to the scene of the crime. Yellowjackets, bald-faced hornets, and other undesirables will soon finish off the job the robbers began.

Even a strong colony can be destroyed if the workers of another strong colony get a foot in the door. Then, too, bees from multiple hives may arrive and take down the strongest among them. Don’t assume. Look carefully.

Part of the aftermath of a robbing frenzy is the transfer of Varroa mites from the vanquished colony back to the marauding colony. In some cases, colonies with no previous mite problems are suddenly overwhelmed with mites brought back with the stolen honey. This phenomenon is one reason very strong hives can collapse quickly in late fall. As I mentioned in a recent post, the strength of a Varroa mite infestation is strongly influenced by the number of mites brought in from the outside, and robbing is a major source.

So what’s a beekeeper to do?

The first thing a beekeeper needs to do is recognize a dearth when it happens. My previous post, “How to recognize a nectar death” contains a list of things to look for in addition to observing your local flora.

Once you recognize a dearth, you may want to take actions to minimize the damage a dearth can cause. Listed below are some considerations for colony management.

  • Feeding syrup during a summer dearth is a two-edged sword. On the one hand, if your colony is low on stores, feeding may keep them from starving. On the other hand, the presence of feed can quickly alert robbers to a feast. If you decide to feed, resist using an entrance feeder because the odor will bring robbers right to the front door. Instead, use an internal or enclosed hive-top feeder and avoid drips and spills.
  • If you have a strong nectar flow in autumn, feeding bees during the summer dearth has advantages. Normally, the hive population drops during a dearth because when nectar stops coming in, the queen restricts her egg laying. A good supply of syrup keeps the colony population higher, and a bigger colony going into autumn will be better able to harvest the late nectar flows.
  • If you decide to feed colonies during a dearth, do not use essential oils or Honey-B-Healthy. At this time of year, these products can entice bees from miles around. Don’t worry, your bees will have no trouble finding the syrup in their hive.
  • Reduce entrances. Robbing is always a possibility even if you are not feeding. Reduce your entrances and, for small or weak colonies, consider using a robbing screen.
  • Close upper entrances. It is harder for your bees to defend two or more entrances. If you are using upper entrances, close them off during the dearth. If you need upper ventilation use a screened inner cover or an eke (two- or three-inch super) with screened ventilation ports.
  • Do not put community feeders or wet frames near your apiary. Either one can start a frenzy that invites robbers to your area. If you want your wet frames cleaned by your bees, put the frames in a super inside the hive.
  • If possible, schedule hive manipulations for late in the day. Bees go home at night, so opening hives late in the day allows time for the odors to dissipate before morning. It also gives nighttime scavengers an opportunity to clean up any drips and spills.

Plant for the lean times

Although it is too late for the current year, planting summer-flowering plants can help ease the transition from lots of nectar to hardly any. Even if you don’t have enough flowers to feed an entire apiary, a few summer flowers can often satisfy the wasps and hornets, diverting them from your hives.

Most often beekeepers plant spring-flowering plants for their bees, but the spring is usually rife with flowers already, which limits the value of your planting. In the future consider searching out those plants which bloom in the heat of the summer. For example, in my area many August flowers are just coming into bloom, including joe-pye weed, borage, oregano, lemon balm, mint, phacelia, autumn joy sedum, open-centered dahlias, and poppies. Give the “late-bloomers” a try, and give your bees a much-needed summer treat.

Honey Bee Suite

Bees on dahlia Pixabay

Honey bees on an open-centered dahlia, a good late bloomer for many types of bees. Pixabay public domain photo.


  • Here in the Hudson Valley (at least in 2016) there’s been no summer nectar dearth at all. In fact from mid-March (when the “purple dead nettles” started), there’s been enough flowers to keep the colonies strong. By early April there were 10,000 purple dead nettle flowers on the eight acres where I work. By April 17 there were a million (saw 70 bumble bee queens at once and honey bees galore). Ten days later there were five million purple dead nettle flowers and the honey bees thrived. Dandelions peaked on April 25, motherwort flowers overlapped them and mint followed by purple loosestrife and just arriving goldenrod. The first-year colony survived and swarmed. It seems to me that the reason I know of 12 honey bee colonies in one square mile is thanks to purple dead nettle flowers. When I recently travelled the valley, I found huge patches of isolated flowers (normally covered with honey bees), without a single honey bee. I thought, “My guess is that there weren’t enough early purple dead nettles.” When purple dead nettle flowers were in bloom in the area, not a single bumble bee ever went on a dandelion. Honey bees also prefer purple dead nettles, but some did go on dandelions.

  • I’ve noticed that some of my bees turn incredibly aggressive during hive inspections with a constant supply of bee torpedoes if there is a shortage of food. More so with bees in my rural apiary than those in my back garden. Not a pleasant experience!

    • I believe Philippa might say the bees are coming at her, “shoving” her with their body weight, a precursor of getting stung…

      • That was a thought, we had some chilly late afternoons in CT. 40’s in the AM. I have to split the boxes to due a thorough inspection and have tons of yellow jackets from the orchard , hopefully they are elsewhere.GUN SHY after getting 2 hives robbed out last year and no noticing.

  • One of my boxes seem very light. I’m afraid of no honey. Should I feed 1 to 1 sugar syrup? These are new hives this year so no honey supers used. When I did check 3 weeks ago there was ample nectar and some honey.

    • Barb,

      If you have been experiencing a nectar dearth, your bees may have already eaten through a lot of their stores. If the hives are too light for the bees to make it through the winter, you will definitely have to feed them (unless you have a heavy fall nectar flow).

    • Jim,

      You can feed bees both sugar water and pollen in a dearth if they need it. Did you look inside? If they have plenty, you don’t need to feed either. But if they are short of one or both, then go ahead and feed.

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