Due to hot and dry weather in many areas, beekeepers are already messing with robbers. I’ve heard sad stories from beekeepers whose full honey supers suddenly turned up empty, and others whose smaller colonies were wiped out. This is not unusual, but it can bewilder new beekeepers.
Besides taking the honey, the presence of robbing bees attracts wasp predators, especially yellowjackets and hornets, who dine on all aspects of a beehive: bees, brood, honey, and bee bread. Once they get started, both robbers and wasps are hard to stop, so prevention is key.
Having lost hives to these predators myself, I believe in reducing entrances early—much earlier than seems necessary. If you think of an entrance of a source of ventilation, and keep it wide open, you are more apt to get caught by a robbing frenzy.
Think of an entrance as an entrance for everyone—your bees, other bees, and predators. If you want ventilation, use alternate devices such as a screened bottom board, screened inner cover, screened ventilation ports, or similar. A large entrance is not ventilation—a large entrance is trouble.
Where I live, I reduce the entrances when I remove the honey supers at the end of June. The key to entrance size is to make it commensurate with the size of the colony.
Most standard entrance reducers come with two hole sizes, one about 3/4-inch long, and one a little less than five inches long. I sometimes use the longer opening for large colonies, but I rarely use the 3/4-inch size except for the smallest of colonies. Instead, I like a two-inch opening for most hives during a dearth. You can make them easily out of a piece of 1-by-1. I made a bunch one year with various hole sizes. When it comes times to reduce, I carry the bucket of reducers with me and select a size on a colony-by-colony basis.
Last week I was near my smallest hive when I noticed a commotion on the landing board. When I got closer I was amazed to see this little colony with a much-reduced entrance had taken down a bald-faced hornet. Way to go! They were in a tizzy trying to remove it, with two to three bees pushing and dragging to no avail. (After I shot the photo, I gave them a hand.)
The other thing that works well is a robbing screen. I have some that I bought online, but I think they are too complicated and too expensive. I don’t need all the adjustable entrances and swinging doors, so I’m in the process of making a simpler design which I will share once I’ve tested it. Remember that robbing screens work just as well for yellowjackets and hornets as they do for robbers, so don’t hesitate to use them.
Quick! We’ve got to dump the body! © Rusty Burlew.
Robbing bees: questions and answers
What is robbing?
Robbing is a term used to describe honey bees that are invading another hive and stealing the stored honey. The robbing bees rip open capped cells, fill their honey stomachs, and ferry the goods back home. They will fight the resident bees to get to the stores and many bees may die in the process.
When does robbing occur?
Robbing can occur anytime during the year, but it is most evident in the late summer or early fall, especially during a nectar dearth. Robbing can often be seen in the early spring as well, most frequently before the first major honey flow.
Why does robbing occur?
Honey bees are compulsive hoarders. They will collect nectar or honey from any source they can find, and that includes a poorly guarded or weak hive. Personally, I think “looting” is a better description because, like human looters, they tend to prey on the weak and vulnerable, especially a hive with a problem.
Think of it like this: It is a hot August afternoon. It hasn’t rained in weeks. The flowers are long past their peak and the few that remain are crispy. A gang of bored workers with too much time and not enough to do is hanging out, looking for trouble. Suddenly, one of the gang picks up on a scent . . . sweet! It’s coming from a nearby hive where the beekeeper has spilled some syrup. A few scouts check it out and believe they can overpower the lethargic guard bees lounging in the heat. Within minutes the dancers post directions on CombBook and the siege is on.
How can I recognize robbing?
Sometimes a weak hive will suddenly come to life. You, a new beekeeper, are ecstatic because a hive you thought was dying is now thrumming with activity—bees are everywhere. You think the colony has finally turned itself around. But when you go back the next day, no one is home. The honey frames have been stripped clean, bees lie dead on the ground, and the small colony is decimated.
At other times, the signs are more subtle:
- Fighting bees tumble and roll—sometimes on the landing board, sometimes in the air.
- Dead bees lie on the landing board or on the ground in front of the hive.
- Robbing bees can often be seen examining all the cracks and seams in a hive, even at the back and sides.
- Robbing bees are often accompanied by wasps that are attracted to the dead bees as well as the honey.
- Some of the bees in the fray may appear shiny and black. This appearance is created when the bees lose their hair while fighting. Both attackers and defenders may have this appearance.
- Robbing bees never carry pollen on their legs.
- Robbing bees often sway from side to side like wasps, waiting for an opportunity to enter the target hive.
- Pieces of wax comb may appear on the landing board as the robbers rip open new cells.
- Robbing bees are louder than normal bees.
- Because robbing bees are loaded down with honey when they leave the target hive, they often crawl up the wall before they fly away and then dip toward the ground as they take off. This may not be immediately obvious, but if you study them for a while, you can see it.
What can I do to prevent robbing?
It is much more effective to anticipate robbing and take preventive measures than to try to stop it once it starts. Here are some strategies that may work—at least some of the time.
- Reduce entrances at the first sign of a nectar dearth. Bees can successfully defend their hive if they have a large enough population and a small enough entrance.
- Many beekeepers have observed that Italian bees rob more often than other sub-species. If you keep Italians, you should be more vigilant.
- It appears that queenless hives are more vulnerable to robbing than queenright hives. Make sure all your hives are queenright as robbing season approaches.
- Entrance feeders seem to promote robbing more than other feeders, probably because the food source is so near the hive opening. Use some other type of feeder during nectar dearths.
- Small or weak hives are particularly vulnerable. Consider combining such hives before a nectar dearth.
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- Commercial robbing screens are highly effective devices that allow the resident bees to get in and out while discouraging the robbers. These can be especially valuable for use on weaker hives that you do not want to combine.
What can I do to stop it?
Once it starts, stopping a robbing frenzy is not easy.
- Smoking will not stop robbing, but it will give you a reprieve while you close up the hive. Get the smoker going and set it next to the hive while you work.
- Reduce entrances to a very small opening. Some beekeepers stuff grass in the entrance—a technique that keeps out the robbers but allows some airflow.
- If robbing is really intense, you can simply close up the hive opening with hardware cloth or screen in a size the bees cannot get through (#8 or #10 work well). Close up the hive completely for several days until the robbers give up. If necessary, be sure to provide feed, pollen, water, and ventilation for the confined colony.
- A water-saturated towel thrown over the hive confuses the robbers but allows the hive residents to come and go from underneath the towel. Evaporation from the towel keeps the hive cool.
- Install a robbing screen. This device re-routes the hive residents through an alternative entrance while the robbing bees, following the scent from the hive, continue to butt into the screen.
- Some beekeepers spread a commercial product such as Vicks Vaporub at the entrance to the colony. This product contains strong-smelling compounds such as camphor, eucalyptus oil, and menthol that mask the hive odor and confuse the robber bees.
- Some beekeepers recommend removing the lids from all the hives in the apiary. The theory is that the bees become so busy defending their own hives that they stop robbing other hives. However, if the robber bees are coming from somewhere other than your own apiary, it won’t work. Also, it will do nothing to stop wasps and other predators from entering your hives at will. This is not a good strategy for an inexperienced beekeeper.
Rusty
HoneyBeeSuite
This year, when I was building my new hives, I also built 2 robbing screens similar to the one you posted a photo of in a prior entry on robbing. I plan on leaving it on year round.
My last hive was completely devastated (killed) by the robbing bees. I keep Italians and they were robbed out by other Italians when I didn’t have a robbing screen. I have seen combat in my apiary but my colonies are both doing well! Drinking my 1:1 syrup and eating (storing) the pollen patties I give them (I’m trying to build them up).
Thanks Rusty for the information about robbing. It happened to me two years ago with my one and only hive. I was new to the world of beekeeping and I didn’t recognize what was happening and by the time I did it was too late. I felt horrible! I was upset at myself for letting the girls down and was depressed about it, lol. So I jumped back in to it the next year and they are doing great! Thanks again!
Brad
Great info! Can I have permission to use that photo in one of my Poughkeepsie Journal segments?
My brother and I have noticed the common eastern bumble bees are, on average getting smaller. Has anyone else noticed this?
Mike,
Sure. Please give credit and/or a link back to my site. Thank you.
I don’t know much about eastern bumble bees, but I do know that each bumble bee nest has a large variation in bee size. The smallest ones usually stay in the nest as nurses, but sometimes they are out and about.
Rusty, Yes, I’ll mention both! Thanks!
I have had entrance reducers on my colonies for several years now, the entrances are never that wide open space. When I read Honey Bee Democracy, that reinforced my decision. I use the smallest opening, only one hive has the larger one because of major logjams.
Recently, I had to make a make-shift robbing screen (which worked marvelously) by stapling fiberglass window screen around an entrance and creating a tunnel for access for the “right” bees. I’m curious to see your robber screen; my issue with the commercially available ones is that they are not “modular” enough for my set-up, so I end up cobbling together my own.
I have italian bees. I am not sure why I have 2 out of 4 vacant hives. I know that I had mud daubers in one and ants in another. I am wanting to see if I have a been cell to transfer to a new hive to try and start over. Any advice? Thanks Betsy
Hi Betsy,
I don’t think mud daubers would be a problem, although the ants could have been. It’s hard to tell because these pests frequently move in when a colony is weakening for other reasons. I’m not sure what you are asking in your question . . . maybe a typo.
Rusty,
Bumble bee experts have been dumbfounded by the fact that I’ve seen B. impatiens nest entrances with ONLY honey bee-sized workers going in and out all summer. That size and a little bigger are everywhere on flowers here now, at a time when the vast majority of workers are thought to be large? Even 10 years ago it wasn’t rare to see a large worker in July like it is now.
Mike,
The most common bumble in my area is B. vosnesenskii, and I see it in all sizes from extremely large to exceptionally small, but most are mid-sized. Some of the smallest confused me at first; they didn’t seem big enough to be bumbles.
Rusty, So it’s different where you live. The smallness of B. impatiens fooled me into thinking they must be a different species. But Robbin Thorp identified them and said the little and big are just different sized workers.
I’ve successfully stopped robbing by feeding the robbing colonies and halting feeding of the weak colonies. Now my policy is to feed the strong hives only and just share the capped food with the weaker hives. This keeps the robbing hives occupied and gets more comb drawn. I’ve noticed that they love to work, so I give them work.
The above strategy worked when I figured out that my big hives were robbing the little ones by noticing the following:
1. The small hives had lots of wax debris under the hives; ripped open cells confirmed robbing by bees.
2. The large hives suddenly had started putting honey away (in the middle of a dearth).
3. To confirm this, I stood in front of the hives and by very studious attention, was able to see bees leaving the stronger hives and flying directly to the weaker hives.
I have several hives all together and use entrance feeders. I place the feeder one side with a piece of cedar reducing the entrance all of the way to the other side. The next door hive has their feeder placed furthest away from the neighbor hive’s entrance. Left entrance, right feeder, left feeder, right entrance, etc.. . Works just fine. What I think really gets robbers going is scraping off burr comb and breaking honey cells during a late summer inspection, especially if you are casual and slow at this time of the year when opening a hive. AND if you have a screened bottom board. Hello honey drips!
Hi Rusty – My first year beekeeping – one TB and one Langstroth hive, both new using frameless comb. Packages were installed on April 9th, feeders inside the hives – 5:3 syrup with Honey-B-Healthy. Hive inspections after 3-4 days, queens were accepted and laying eggs in drawn comb; Tabor Hybrid Italian in the Langstroth and Russian Carniolan in the TB.
I inspected the hives after 2 weeks, nice straight combs with mostly uncapped syrup, a small band of pollen and some capped brood. I kept the feeders in place through the 2nd week of May when I realized the Langstroth was not necessarily “humming” with expanding brood (I was worried that I may need to add an addition brood box) when I observed really busy activity at the non-restricted entrance, frenzied bees swarming and covering the hive, and exploring every crevice.
Realizing this was robbing I tossed a beach towel over the Langstroth, saturated it with water and closed up the screen bottom board because bees were also covering much of the bottom of the five. This appeared to slow things down but the swarming robbers soon started moving to the entrance of the TB hive about 5 feet away.
Using #8 screen I closed both hive entrances, smeared Vicks Vapor rub around them, made sure the feeders were full and left the hives closed up for 3 days (~75 hrs); the robbers persisted in continuing to arrive each day although much fewer in number and I kept the hives covered with damp towels.
In the mean time I made robber screens for both hives with metal slides to quickly close up the restricted entrances.
After opening the restricted entrances on the tops of the robber screens both hives soon became very busy again with departures and arrivals and syrup levels in the feeders dropped rapidly. The TB hive has a window on the side and it appeared that the hive population increased and was very active at the feeder during the day but less populated around the cluster and feeder at night – all-in-all, the interior of appeared pretty calm, bee business as usual.
Since both robber screens are totally covered with bees, very limited “fighting” was observed, and not an unusual number of dead bees observed around the hives – seldom any on the landing boards… and a number of the robbers arriving are carrying pollen(?), I’m wondering if in some manner a kind of usurpation has occurred with the robbers?
When the packages were introduced into the new hives, the girls busy building comb and easy access for robbers to feeders, could the robbers have adopted (for use of another term) the hive’s scent and gained unrestricted access to the feeders?
Since both hives got “swarmed” again yesterday I closed the robber screen entrances, replaced the syrup with water, closed off the bottom screens and plan to keep them closed for 3-4 days; as mentioned above last time I did that the number of robbers arriving each morning eventually diminished to just a few but within a matter of days the hives fired up again and swarmed.
Any suggestions beyond what I’m doing? I’m anxious to inspect the hives, particularly the Langstroth since I have no idea how the brood is doing, but I don’t want to open them during the day.
Thanks your great web resource,
Doug
Doug,
I don’t know where you are writing from, so it’s hard to speculate. But if you installed in April, I assume you are in the northern hemisphere. Robbing is relatively rare in the spring, especially during a nectar flow. Most places in the northern hemisphere in May have a reasonable nectar flow, and bees would rather collect nectar than sugar syrup. One thing you could do is drop the Honey-B-Heathy, which is a feeding stimulant. You don’t need to be “stimulating” the robbers to eat more.
I assume you are absolutely sure your bees are not just orienting. Spring orientating flights can be pretty intense and look like robbing. I mention that because you saw little fighting and few dead bees, which is suspicious. I don’t like the idea of locking down your bees for multiple days in the spring. I think I would just leave the robber screens in place, but leave one top entrance open for your bees to come and go.
Also, I don’t know what you mean here, “as mentioned above last time I did that the number of robbers arriving each morning eventually diminished to just a few but within a matter of days the hives fired up again and swarmed.” Did your bees swarm? Your narrative doesn’t make it clear, but I wouldn’t be surprised if they absconded, especially if they are locked up for too long in the spring. Just a though.
Good morning Rusty (from fashionable Davis, CA)-
Thanks for the timely response. I watch the hives from my home office and our family room and was taking great pleasure in late April and early May seeing the increasing numbers in “orientating flights” as well as drawn comb building I could observe in the TB. Then a couple weeks back, while working in the backyard I noted a dramatic rapid increase in the number of bees (swarming) around and on the Langstroth; the hive increasingly became covered with bees trying to get access to the hive anywhere possible, even biting/grabbing at small wood knots on the hive body. When I lifted the top to check the feeder (atop a small screened 4×6 inch eke) on top of the inner cover a number of bees had manage to access the medium box for the feeder and the feeder support was packed with bees.
Assuming this was a robbing event I covered the hive with a wet towel, and using an entrance queen excluder I had available I covered it with #8 screen to block the entrance until I could think through what was occurring, and fabricate a robbing screen and proper reducer.
After blocking entrance to the Langstroth, the robbing bees then gradually moved towards the TB so I put on the entrance restrictor until I could fabricate a make shift screen – the entrance to the TB is a two inch hole in a bottom corner, the restrictor reduces it to approximately <1 inch. As I watched the robbing bees transition to the TB entrance (and all other vent openings, hive joints, etc.) I did observe some fighting.
Reading your blog, Michael Bush's book and other resources about robbing I was moving as soon as possible to try and shut it down. Both Michael Bush, and Wyatt Mangum book on TB hives recommended stopping robbing as soon as possible by closing down (weak/new) hives for 72 hours "until the robbers give up…"
Making sure the hives had food, when I checked and refilled the feeders at night I noted bees hanging on the entrance screens and a number of dead bees at the entrance of the Langstroth and inside the TB; I removed the "diseased." After 3 days I opened the hives with restrictors on the entrances but within a matter of a few days a similar "robbing" type event again occurred and both hives were covered with bees attempting to access the hives from any possible opening or crevice.
When checking the hives at night the numbers of bees hang on the screened entrances were few, perhaps a dozen or more – so I assumed the robbers had returned to the hives.
I fabricated and installed proper robber screens on both hives night before last and when I checked the hives the next morning numerous bees were arriving and covering the TB – many carrying pollen and as the day progressed they actually started bearding on the screen and remained there throughout the night and still there today.
I've replaced the syrup with water, which they're consuming – I'll definitely stop adding Honey-B-Healthy when feeding through the summer.
Sorry about confusing you with the term "swarming." The hives haven't "swarmed," during what I believe are the robbing events the fives were covered – sides, tops, and even bottoms with a "swarm" of bees.
Now that I have robber screens in place and the entrances restricted (bees are still covering the both screens) I'm going to open both screened bottoms but keep damp towels just on the tops since temps today will be close to 90 degrees and climbing to 100 degrees later in the week.
Thanks again for your timely response.
Doug
My issue isn’t with locking down the hives for three days, but with doing it repeatedly. That’s why I recommend a robbing screen instead of a lockdown. The colony isn’t any stronger or any more likely to be able to defend itself at the end of each three-period than it was before it. Robbers have good memories, and they will make the rounds of previous scores.
Hi Rusty
Afternoon update – I fired up the smoker and suited up to get a “daylight” look at situations around and in the hives. Although a number of bees appear a bit befuddled by and hanging on the robber screens, hive traffic is much more “normal” compared to what I believe were “robbing events” in that when approaching and viewing the hives, no bump strikes or strafing, or persistent “threats” as I would leave the area.
I removed the top of Langstroth to check water in the feeder; everything appearing much more normal. I also removed the upper box housing the feeder, cracked open the inner cover, drifted in a little smoke and then lifted it off. Figuring the girls had been through enough over the past week or two I didn’t remove or move any frames – just observed a lot of very busy bees on all sides of the natural comb frames which convinced me they’ve drawn comb on all eight frames, which is also consistent with the lines of debris observed on the board removed from the screened bottom.
Same is true for the TB when I checked observed activity on the robber screen and in the hive through the viewing window.
And, the bees entering both hives are carrying good quantities of various colored pollen.
Honey-B-Healthy 5:3 “stimulant” syrup has been moved to the back of the refrigerator until winter if needed, or next spring.
Doug
Hi Rusty –
Here’s a link to a UC Davis Entomology article on Robbing Screens that I thought you might find interesting:
http://entomology.ucdavis.edu/files/147611.pdf
Doug
My one year old hive swarmed a couple of months ago. A week or two ago, I put in the entrance reducer on the smallest setting because I knew the remaining hive would be a little week. I just went out last night and a whole river of yellow jackets and wasps were having a feast. Not a honey bee in sight. There were also white whispy web like things with dark dots in them and long wormy looking things crawling around.
I grabbed the remaining honey supers to store in the freezer in case my remaining hive needed it.
What do I do now to clean up the empty hive and get it ready for a new box of bees in April? The brood box frames are all black and weird looking.
Thanks!
Carrie,
The white whispy webbies and the long wormy things sound like wax moths. Freezing is the best thing to do because freezing will kill all the life stages of the wax moths. Other than that, you can give the equipment as is to a new colony and they will clean it up for you. Brood frames get black from multiple layers of bee cocoons, but that is normal.
Such wonderful and interesting information. Thank you for sharing. I did want to note, however, that the photo here is of honeybees and a wasp, not bees on bees.
Cathy,
If you actually read the article, you will see that it is about robbing bees and how robbing can attract other predators. The text explains that the insect in the photo is a bald-faced hornet, Dolichovespula maculata.