February 2021 – Bee Culture https://www.beeculture.com Mon, 10 Jul 2023 12:00:39 +0000 en-US hourly 1 https://wordpress.org/?v=4.9.23 https://www.beeculture.com/wp-content/uploads/2022/07/BC-logo-150x150.jpg February 2021 – Bee Culture https://www.beeculture.com 32 32 Almond Pollination Math https://www.beeculture.com/almond-pollination-math/ Sun, 31 Jan 2021 18:00:57 +0000 https://www.beeculture.com/?p=37615 By: Joe Traynor

Ask an almond grower what was the most useful class he took in school (including college) and if he (she) thinks about it long enough, the answer should be math, maybe algebra in high school, maybe arithmetic in the 3rd grade. Growers are faced with math problems daily – calibrating spray rigs, figuring the amount of chemicals to apply per acre, filling out use reports, making out budgets and calculating ROI (if you’re fortunate enough to have an ROI).

Virtually every problem facing mankind can be reduced to a math problem, whether landing a vehicle on Mars, projecting the consequences, if global warming is a valid thesis, feeding a growing world population, reducing pollution, returning a Republican to the White House, etc. Little wonder that our greatest scientists – Newton, Galileo, Einstein, Feynman and many others – were (are) primarily first-rate mathematicians.

Rapidly expanding almond acreage coupled with a static, or diminishing supply of bees is causing the almond industry to confront a major math problem: can growers get by with fewer colonies per acre? Here’s the original 1947 UC recommendation: “In general, one hive per acre is ample, even in adverse seasons” (Extension Circular 103, Almond Culture in California). Today, the generally accepted figure is two hives (colonies) per acre, with colony strength rarely defined. Some growers use 2.5 to three colonies per acre as a hedge against poor bloom weather, while others have cut back to 1.5 or one colony per acre but make sure they are getting strong colonies – defined as colonies with eight to 10 frames of bees. Growers that have cut back on colonies have not seen reduced yields, even in 2011, when bloom weather was far from ideal.

Some of the basic math data needed to determine the optimum economical number of colonies needed per acre is given below. Because one can easily get bogged down in this quicksand of data a shortcut (rope) is delivered afterwards. If the heavy dose of figures below is too intimidating, you can cut to the chase further down.

A 3000 lb almond crop has 1 million nuts (assume 350 nuts/lb). Assuming a 50% set of flowers, it would take 2 million flowers to give a 3000 lb crop (recent work by Frank Eischen, USDA, has shown that percent set can vary from 25 to 75%, requiring four million and 1.3 million flowers respectively to attain 1 million nuts).

Almond flowers produce 0.7 to 1.2 mg of pure pollen (up to 2.4 mg of bee-collected pollen; bees add “glue” to pollen). Assuming two million flowers/acre, an almond orchard will put out from five to 10 lbs of pollen per acre. (American Bee Journal, April 2001, pp.287-288)

A frame of bees contains about 1500 bees. An eight-frame colony contains about 12,000 bees; a third of these bees (4,000 bees) will be foraging bees.

Pollen-collecting honey bees usually work four hours/day in almonds (10AM to 2PM). Bees will visit 10 flowers/minute (20 or more, if pickings are slim; less than 10 if they can get a pollen load from a few flowers)

Assuming 4000 worker bees/acre and 100 trees per acre you should see 20 bees per tree during bloom if using one strong colony/acre (about half of those 4,000 workers will be flying or will be depositing their pollen loads in the hive).

20 bees per tree visiting 10 flowers a minute will visit a total of 200 flowers in a minute, or 48,000 flowers in 240 minutes (4 hours).

At 100 trees per acre, there are 20,000 flowers per tree. 20 bees per tree will visit each flower two or more times in one four-hour day (four or more times in two four-hour days). Although it takes only one pollen grain to set a nut, excess pollen deposited on the stigma of the flower stimulates the growth of that one pollen grain.

Individual almond flowers remain receptive for two to four days but are most receptive the first two days after they open (UC).

The effective blooming period (when all flowers are receptive) can be from three to 10 days. The more the bloom is strung out, the more time bees have to complete the pollination job.

Frank Eischen (USDA) has shown that one strong colony, equipped with a pollen trap, can collect six lbs of pollen in a day (12 lbs over a two-day period at peak bloom; significantly less than six lbs/day on the days before and after peak bloom). This colony had to stray out of its one acre allotted area to get six lbs. in a day; pollen traps cause colonies to collect more pollen than they normally would and they do so at the expense of colonies without traps.

An eight-frame colony will collect significantly more pollen than two four-frame colonies. (American Bee Journal, Feb. 1977, p.78; California Agriculture, UC, August, 1970).

Bee flight hours and statewide almond yields, 2011 and 2012 

2011: 47 hours, 2650 lbs/ac. 2012: 65 hours, 2550 lbs/ac. (est.) Bee flight hours, courtesy of Tom Dunklee, Global Climate Center are for Merced but hour differences for other almond areas are similar (Sacramento Valley stations averaged only 22 bee hours in 2011).

Now, forget all the above data and calculations – here’s the shortcut, the rope: Using strong colonies, honey bees collect the daily ration of pollen provided by almond flowers by 2 PM (or sooner). Walk your orchard after 2 PM and rub the anthers of the flowers between your thumb and forefinger; if the bees have done their job, you should see little or no pollen on your fingers – the bees have finished their work for the day and are too smart to expend valuable energy for a minuscule reward (to verify this, check the entrances of your hives for returning pollen-collecting bees). If there is still pollen on your flowers after 2 PM you need stronger bee colonies or more colonies. Can you get by with fewer than two colonies/acre? Using the 2 PM orchard walk outlined above, it is certainly possible, but make sure you rent eight to 10-frame colonies. The 1947 UC recommendation of 1 hive/acre (with no strength specification) could well hold true today, but only if the hives contain strong bee populations.

Almond pollination is a community effort so make sure your neighbor rents colonies of sufficient strength to prevent your bees from seeking bigger rewards elsewhere. Because one eight-frame colony will collect significantly more pollen than two four-frame colonies, paying a premium price for the stronger colonies is a worthwhile investment. And remember that a hive is the structure (usually wooden) that contains the colony of bees. Hives can contain 0 to 20,000 or more bees. In any given year, there will always be plenty of hives available for California almond orchards, but not all orchards will be supplied with strong bee colonies.

The argument, and it’s a good one, against cutting back on bee colonies goes like this: I know I can get by with fewer bees most years, but for that one year when the bees only get an hour or two to do the job, I want as many bees out there as possible – it’s good insurance. 2011 was a year when intermittent rains confined bees to their hives for extended periods. Bee flight hours for 2011 were the lowest in the 10-year period these hours have been recorded – 22 hours in the Sacramento Valley – yet the 2011 almond crop hit an all-time record of 2650 lbs/acre. Even in a poor-weather year, there should always be enough bee-flight hours between storms to allow strong bee colonies to do their job. If there is only one hour of decent bee weather over the entire pollination period, sure, you would benefit from more bees. Such an event is highly unlikely, but in our current era of unlikely weather events, it’s certainly possible. If forecasts indicate a prolonged monsoon event with maybe only an hour or two of good weather over the entire blooming period, then ordering more colonies would be prudent. Although there probably wouldn’t be any extra bees in California, beekeepers in Texas and Florida often have bees available after almond bloom starts but would need a few days notice to get them here. Even if extra bees did give you good pollination in a one-hour year, there’s a good chance that bloom-time diseases would take your crop.

Note: The data figures given above are, in many cases, best guesses; actual figures can vary 100% or more from those given. Hopefully these figures will be refined in coming years and a skilled mathematician will calculate a more exact figure for the optimum number of colonies/acre that almond growers should use.

When the Pollen is Gone

Once bees have stripped the almond pollen from your orchard, the pollination game is over – no pollen, no pollination. A strange phenomenon, perhaps unique to almonds, occurs when the pollen is gone – bee activity often increases! You will often see more bees/tree after your trees have been pollinated. Look closely, though, and you will observe that these busy workers are all nectar-collecting bees, pushing their tongues to the base of the flowers to suck out the sweet nectar. Almond flowers release most of their nectar after the flowers are pollinated. We learned in grammar school that flowers produce nectar to attract bees to transfer pollen, so what’s going on here? At this time, we don’t know. Although there is no proof, some have speculated that the sugar-laden almond nectar nourishes the small developing nutlet, helping it to survive post-bloom nutlet drop. Some growers release their bees after all the pollen is gone, but most won’t release bees until they see no more flowers. If you decide you want all or most of your bees removed from your orchard when there are still many nectar-collecting bees working (but no pollen-collecting bees) you may find beekeepers reluctant to move them out, as almond nectar is a valuable food source for bees. Unless bees have another flower source to go to (as would Florida or Texas bees) they are better off remaining in the orchard until the last drop of almond nectar has been extracted.

Beekeeper Math

Beekeepers that attempt to satisfy almond growers demand for strong bee colonies are faced with a difficult choice: spend the necessary money to produce such colonies, or rent weaker colonies at a reduced price. According to UC Extension Apiculturist, Eric Mussen, “four frames of bees is the size a Central Valley California colony is likely to be (if it survives) when it is not fed extra syrup and protein during the year.” (Jan/Feb 2010 Newsletter, From the UC Apiaries). Dr. Mussen estimates that beekeepers must spend $120/colony to provide four-frame colonies and $200 to $220/colony to provide 8 to 10 frame colonies (these cost figures are likely 10% higher for 2013 than they were in 2010). A beekeeper is better off, probably far better off, renting a four to six-frame colony for $150 than renting an eight to 10-frame colony for $200. Even with record almond pollination fees, building high bee populations that continue to consume expensive feed during the Winter (both before and after almond bloom) does not make economic sense for many bee operations. With Varroa mites, viruses and diminished bee pasture taking an ever-mounting toll on honey bees, today’s beekeeper feels fortunate if he can cover operating expenses, let alone attain an ROI (a term foreign to many beekeeping operations).

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Refractometer – All You Need to Know https://www.beeculture.com/refractometer/ Sun, 31 Jan 2021 18:00:45 +0000 https://www.beeculture.com/?p=37608 By: Hanna Bäckmo

Honey typically contains somewhere between 14% – 20% water, seldom less, sometimes more. Honey contains lots of other substances as well, such as carbohydrates, mineral substances, enzymes, organic acids, proteins, and vitamins, but it is the water that we are going to concern ourselves with in this article. The water found in honey is mostly residual moisture after the process of nectar ripening. I say mostly, because as honey is hygroscopic, it absorbs moisture from its surrounds. If honey is stored incorrectly after extraction, its water content can increase. Frames of uncapped honey stored incorrectly prior to extraction can also absorb moisture and thus increase the water content of the honey. The percentage of water in honey depends on nectar origin, honey maturity and environmental factors such as climate, weather, and storage.

The water content of honey largely determines if the honey can stay fresh. The lower the water content, the better the honey will keep. As a beekeeper, being able to produce honey with the ‘right’ moisture content is imperative, particularly if you intend to sell your honey or store it. Honey with low moisture content will crystallize, or granulate, rapidly, but other than that it rarely gives any trouble. Where things go wrong is when honey with high moisture content is harvested and subsequently stored incorrectly, as this can lead to fermentation of the honey. This would render it unsuitable for resale as anything other than baker’s honey.

Fermentation

In order for fermentation to occur, three components need to be present. Yeasts, relatively high moisture content (in excess of 17%), and a suitable temperature for the yeasts to grow (10-30°C approximately). Take away at least one of these components and the honey will not ferment. For instance, store the honey below 10°C and/or ensure that the moisture content is low. You can kill the yeasts by heating the honey also, but this is not recommended as the heating process will destroy or reduce the effect of the enzymes present in honey, as well as altering the flavour. Yeasts are brought into the hive with the nectar. Many yeasts will die when the nectar is dried out and the sugar concentration rises. However, some remain in the honey. You will find the greatest amount of yeasts in uncapped or unripe honey, and it also contains more water than its capped or ripe counterpart. Yeast needs nitrogen and mineral salts to grow, which is why some honey which contains a lot of those substances will ferment faster.

There is no universally accepted number for what moisture content honey should have, but a good guide to aim for is somewhere between 16-18%. Below 17% moisture content, no fermentation will occur. At 18% no fermentation will occur unless there are large amounts of yeasts present. Above 19% moisture there is a definite danger of fermentation regardless of the amount of yeasts present. At 20% and over, yeasts will multiply freely, and the higher the moisture content, the more rapid the fermentation becomes.

This presents the need for the beekeeper to be able to accurately measure the moisture content in honey. In the apiary, we may do a simple shake-test to see if the honey is ripe enough to be harvested, (give frames of uncapped honey a good shake, if the honey comes out, it is not ready, and if it stays in the comb, it can be harvested and extracted alongside the capped frames). But when it comes to bottling and storing the honey, we need to be a bit more scientific than that.

Measuring moisture content in honey

When light passes through a substance, it changes direction. This is called refraction. The amount of refraction that the light undergoes depends on the amount or concentration of solids in the solution. A refractometer is an instrument that measures the refractive index of a substance, or, in layman’s terms, the degree that light, passing through a solution, is bent. By measuring the difference between the angle of the light coming in (incidence) and the angle of the light going out (refraction) of a substance you have the components needed to calculate the refractive index. If you look at a glass of water with a straw in it, you will notice that the straw looks as if it is bent or distorted. This is because the light passes through the glass more quickly than it does through the glass and water. Similarly, light will pass through honey with fewer solids faster than it will through honey with many solids. Hence, the refractive index of honey will change relative to the amount of sugars, pollen, and other substances present in the honey.

The refractometer is a very useful tool that measures the refractive index, does the calculations, and presents a reading. Refractometers are used not only by beekeepers. Different types of refractometers are used in other professions and industries such as medicine, brewing, machine- and car industries, gemology, and are used to measure salinity in aquariums, etc. The amount of solids in a solution is measured on a Brix scale, where each degree of Brix (°Bx) equals one percent solids (There are other scales also, but the Brix scale is used when measuring sugars). So, on a refractometer using the regular Brix scale, 20 degrees Brix means that the solution contains 20 percent solids. Anyone familiar with honey refractometers will be aware that they do not present the readings as solids in water, they work the opposite way and give measurements for water in solids. The scale works in reverse, and what we see is the water content of a solution as opposed to solid content. They are not designed this way to confuse, but to make the process of measuring moisture content in honey more straight forward for beekeepers, and more exact. The honey refractometer also does not commonly have the full 0-100 Brix scale, but typically displays values between 10-30 (% water) or 70-90 (% solids). Both a regular refractometer and a honey refractometer can be used to measure moisture content in honey, the only difference is how the results are read.

The refractive index will change slightly as the temperature changes so most refractometers are designed to make corrections based on temperature using Automatic Temperature Compensation, or ATC.

Different refractometers

If you are considering getting a refractometer to measure your honey, it is advisable to get a honey refractometer as opposed to a regular one. There are many honey refractometers available on the market, most are portable and easy to use. There are both analogue and digital instruments available, ranging in price from around 20 Euros or about $25US to several hundred and even thousands for laboratory style pieces. You can of course fork out for a top of the range digital version, but a standard analogue honey refractometer will give adequate readings. The readings will not be completely accurate but typically within one degree Brix, or 1 percent, fault margin, so will give a good indication of the moisture content in your honey, provided that the refractometer is used correctly and is calibrated properly.

Calibration

The first thing that you have to do with your refractometer is to calibrate it. By calibrating it, you are using a reference liquid or solution that you know the Brix reading of (or the moisture content) and adjust the instrument so that you get the same reading on its Brix scale. Some refractometers are already calibrated, but it is always good to re-calibrate it yourself first before using it to test your honey. The screw used to adjust the reading could have become loose in transport, and it is good practice to recalibrate your instrument after it has been unused for any length of time.

Reference solution

This is what you can see when you look into the eyepiece of a honey refractometer. The honey measured here has a moisture content of approximately 18.5%

When calibrating the refractometer, you need to make sure that you use a reference solution that is suitable for your particular instrument. For instance, if you are using a honey refractometer with a reduced Brix scale, such as 90-60 Brix (or 10-30% water) which is common for honey refractometers, you may have problems calibrating it accurately if your reference solution falls outside of those measurements. Many of the cheaper refractometers do not include any reference solution, and unfortunately many also come with the wrong instructions. It does not necessarily mean that there is anything wrong with the instrument itself, only that you have to do a bit more work to get it right. If you do not have a reference solution supplied with your instrument, it is possible to use oils that you have in your kitchen to calibrate your refractometer. For instance, extra virgin olive oil can be used, as can liquid paraffin. Extra virgin olive oil measures 71-72 Brix. If using this oil to calibrate, set it at 71.5 Brix (or 27% water). Liquid paraffin has a moisture content of 24.5%. If you are unsure of the moisture content or Brix reading of a substance, there is little point in attempting to use it as a reference solution. If, however, you are stuck and you happen to have access to someone who has a refractometer that is properly calibrated, you can use this instrument to determine the Brix of a substance, and then calibrate your own refractometer accordingly. This is obviously a cumbersome way to go about it, so it is easier just to ask them for a few drops of their reference solution if it falls within the Brix scale on your refractometer. It is always good to have a small bottle of reference solution stashed alongside the refractometer in your honey room. Write down the Brix or the moisture content on the bottle so that you do not have to rely on your memory, look it up or make guesstimations the next time you need to recalibrate.

This is how to calibrate an analogue refractometer (for digital versions, follow the instructions provided with the instrument):

• Lift the clear panel that sits on top of the glass and clean the glass or prism with a lint free cloth. Then add a couple of drops of the reference solution to the glass and spread it out. Make sure there are no air bubbles in the reference solution and close the panel. Any air can be squeezed out by gently pressing down the panel and wiggle it slightly.

• Remove the cover for the calibration adjustment piece and have the little screwdriver at the ready.

• Hold the refractometer towards a bright light and look through the eyepiece. Focus the eyepiece if necessary, to make the lines and numbers clearer. You should see a field of blue and another field of white, with a very distinct line where the two fields meet. This line marks the Brix of the substance measured.

• While still looking through the eyepiece, insert the screwdriver into the screw in the adjustment piece and turn it until the line correlates to the number for the known Brix reading of your chosen substance.

• Your instrument is now calibrated and ready to use. Replace the cover for the calibration adjustment piece and clean the clear panel and prism using a damp soft lint free cloth.

Refractometers need to be recalibrated regularly, at least every season but preferably more often as the instrument is sensitive. The adjustment screw can accidentally loosen during handling causing the reading to change, and it is also somewhat sensitive to changes in temperature.

How to use an analogue refractometer

Once properly calibrated, refractometers are delightfully easy to use. Make sure the honey is well stirred (honey that has been sitting in a bucket or jar for some time will often have different readings in the samples taken from the top and bottom) and that the honey is the same temperature as the refractometer, ideally room temperature.

• Lift the clear panel that sits on top of the glass and clean the glass or prism with a lint free cloth. Then add a couple of drops of honey to the glass and spread it out. Make sure there are no air bubbles in the honey and close the panel. Any air can be squeezed out by gently pressing down the panel and wiggle it slightly. Make sure not to put too much honey on the prism as it can make it difficult to get a clear reading.

• Hold the refractometer towards a bright light and look through the eyepiece. Focus the eyepiece if necessary. You should see a field of blue and another field of white, with a very distinct line or border where the two fields meet. In most analogue refractometers there is an ascending Brix scale in the middle, and a descending water content scale on the right. The line will go through both scales and thus you can read both the Brix and the water content in percent in the same reading.

• Clean the clear panel and prism using a moistened soft lint free cloth and repeat.

• Take multiple readings and calculate the average, especially if measuring the moisture content of a bucket or large amount of honey.

• If the honey is to be stored, write down the moisture content of the honey on the bucket alongside the batch number and extraction date.

• When finished, clean the refractometer, and put away in its box. Be careful with the prism as any scratches can impair or interfere with the readings.

In order to ensure that the honey does not contain excessive moisture, when harvesting make sure that the honey in the frames is ripe and take frames with capped honey only. It is nearly impossible to completely exclude uncapped honey when harvesting and extracting, particularly at the end of Summer harvest, and many beekeepers will include up to 10 percent of uncapped cells. Take off the honey supers in the morning so that the bees can dry out the honey over-night and to ensure that there is no new nectar coming in. If there are a lot of uncapped frames to be harvested and extracted, they can be dried out prior to extraction using a fan and/or dehumidifier. The honey can also be extracted and stored separately. Honey with high moisture content for own use is best frozen in jars and taken out as they are needed. Extracted honey with high moisture content can be placed on trays and dried using a fan and/or dehumidifier. Smaller amounts can also be mixed in with honey with low moisture content. If doing this, ensure that the end result is a honey that has no higher than 17-18% moisture content.

Finally, I would advise anyone who harvests honey to use a refractometer to measure the moisture content of the honey, whether it is for own consumption, gifts, or sale.

For any comments, feedback, or suggestions, please email Hannabackmo@yahoo.se

Reprinted with permission of “The Irish Beekeeper.”

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The Rational World of Robber Bees https://www.beeculture.com/the-rational-world-of-robber-bees/ Sun, 31 Jan 2021 18:00:39 +0000 https://www.beeculture.com/?p=37617 By: James E. Tew

It’s a problem because we say it is…

Bee colonies robbing each other is a problem because we – as concerned beekeepers – say it is. And beekeepers say it’s a problem because apiary bees become defensive (and aggressive) within the area and secondly, weaker colonies can actually be robbed to death. These common beeyard results are not good – at least not for the beekeeper.

In some way, it would seem that the negligent beekeeper should have done something to forestall this rampant behavior. Admonishments to address honey bee robbing are in every basic beekeeping book – every last one of them. Things to do and things never to do, that control or prevent robbing are presented in concrete fashion. It’s like, “Here’s the problem,” and “Here’s the answer.” Advice from others free flows. Dealing with robber bees is an old and common apiary concern.

From another view, criminal bees seem perfectly happy to pillage the area. If entire book sections and years and years of advice abound, why do bees still perform the behavior so readily and so predictably? Clearly, there is some advantage for the bullish colony to forcibly take all the resources from a sad colony neighbor. There must be profits for the aggressor colony. To beekeepers, the activity appears to be criminality in the natural bee world, but to foragers, it’s all in a day’s productive work.

In his chapter in The Hive and the Honey Bee1, Dr. Norm Gary wrote, “Robbing behavior is, unfortunately, an anthropomorphic description of a special foraging behavior in which bees collect nectar and honey at hives or on unprotected combs of honey rather than foraging on flowers.”

I guess it could be said that Mother Nature is frequently not loving and nurturing. For instance, in an unforgiving world, I established two hypothetical colonies. One developed a large, healthy population and has hoarded surplus stores. It has done well during the season just past. It’s near colony neighbor, didn’t do as well. The reasons are irrelevant. Given the same environmental benefits, one colony did better than the other. One had a greater population than the other and more food reserves. That’s all that matters.

For honey bees in general, what would be a better survival scheme? To have one “good” colony and one “okay” colony try to survive the winter or to combine them and have one “great” colony try to get through the upcoming Winter?

James E. Tew

Enter the beekeeper

The beekeeper has invested money and time in both colonies. They will try to subsidize colony food reserves and possibly feed both colonies to get them through the Winter. It’s what we beekeepers do. We have two expensive queens – true fact that one must be better than the other – and we bought two packages (more money), and too often, overall hive numbers are an indicator of our beekeeper value. Somehow, it would appear that the more hives a keeper has, the greater the level of competence. Not necessarily, but that is a story for another time. Bottom beekeeper line? We would want both colonies to survive. To the beekeeper, it would seem that two colonies are better than one.

Nature’s opposing view

The biggest challenge a bee colony faces in a temperate climate is the long, foodless Winter period. Without enough food reserves, all the good health, great queens, genetics, Winter packing, and hive ventilation is for naught. Without adequate food reserves, the wintering colony will starve before Spring.

As the Autumn nectar flow wanes, and all flowering resources have been exploited to all profitable degrees, then the primary foraging source becomes the honey reserves in neighboring colonies. If the neighboring colony is not strong enough to defend its stores, then it most likely was not strong enough to survive the Winter. As Dr. Gary wrote in the reference presented about robber bees, they are not criminals so much as they are relentless foragers – even if it means foraging in their neighboring colony’s pantry.

Are these bees forager or thieves?

Robbing is more than a simple beekeeper inconvenience

Online, it is essentially impossible to uncover academic information about the biology and ecology of robbing behavior. Hundreds of listings immediately present generalized robbing control methods with time-honored recommendations. Don’t have colonies too close together. Reduce entrances. Don’t open colonies during a dearth. Don’t leave comb scraps exposed. If you have managed bee colonies more than a full year, you have read the generalized recommendations. There is nothing wrong with this advice. No harm done. But know this, bee colonies will rob each other, and they will do it every season. The only way to completely eliminate robbing behavior is tremendously reduce colony density. In a robber-free world, a colony would have no near bee neighbors.

Robbing behavior is more than unemployed foragers, rife with frustration and boredom, searching anywhere and everywhere for food in any form. Colony foragers are aggressively competing with foragers from other colonies – in a life and death arena.

I have taken the following insert, verbatim from Wikipedia.
“In ecology, scramble competition (or complete symmetric competition) refers to a situation in which a resource is accessible to all competitors (that is, it is not monopolizable by an individual or group). However, since the particular resource is usually finite, scramble competition may lead to decreased survival rates for all competitors if the resource is used to its carrying capacity. Scramble competition is also defined as “[a] finite resource [that] is shared equally amongst the competitors so that the quantity of food per individual declines with increasing population density”.[1] A further description of scramble competition is “competition for a resource that is inadequate for the needs of all, but which is partitioned equally among contestants, so that no competitor obtains the amount it needs and all would die in extreme cases.”

Robbing seems to be a form of Scramble Competition – at first

For bee foragers, it’s a timed game. The clock is operated by the nectar flow. While the flow is ongoing, each colony forager maniacally gathers whatever she can bring back to the colony’s storeroom. At this point, I simply cannot get off the subject of this article, but R. Page, in his book, “The Art of the Bee3,” reveals that not all foragers are out for the biggest bang for their buck. While most foragers are going for the maximum load, some scouts are searching for alternative sources that are sometimes lesser food producers than what is presently available to the colony. So much as possible, no food source (blossom or otherwise) is ignored, but it would be wrong to let the reader think that during good nectar and pollen flow times, all foragers come back fully ladened. As Page discusses, foraging decision-making is a complex issue.

What about Contest Competition?

Does robbing behavior shift to Contest Competition as the season progresses? So hypothetically, all foragers are out on the game field, being as successful as possible and the game clock, the nectar flow, runs out. The ending bell, the first frost of early Winter, sounds and floral foraging comes to an end. Commonly, food dearths occur in mid-Summer or during Winter. Flowers are no longer producing food rewards. That is when I suggest that the second type of interspecific competition comes into play – Contest Competition. Contest competition4 is a form of competition where there is a winner and a loser and where resources can be attained completely or not at all. This is the case of the robber and the hive being robbed – one winner and one loser.

Though nectar sources have finished flowering, the weather is still warm enough for bee flight. Experienced foragers are still on the job, but no sources are out there. Robbing conditions are at hand. Beekeepers know that this is the time that colonies begin to attack each other. That some colonies survive the Winter is paramount to the survival of the species. If one wants to see the concept of “Survival of the fittest” in play, just watch the pandemonium that robbing causes within the apiary.

Pure frenzy

Historically, still photos have been presented to show events that really couldn’t be shown in a still photo. The wonderment of watching a bee dance is completely lost in a still photo. I write about a dozen articles a year asking what washboard movement is showing. A still photo does not capture the washboard behavior movement. Until you see hundreds of bees performing the rhythmic motion of the unexplained behavior, a beekeeper cannot grasp the event.

Robbing frenzy is one of those bee behavioral events that is poorly captured by still photography. Look at my short clip at: or look at any other bee robbing clip on the web. True chaos. Pure frenzy. To fully appreciate, you simply must see and hear the hellish event. I don’t have words and terms to express what a full-featured robbing event looks and sounds like.

I get it – as best I can

Okay. In some fashion, using some rational foraging plan, bees have “scrambled” to garner what they could from flowering plants in their immediate ecosystem. That aspect of the season ending, foragers moved to some other type of non-blossom foraging paradigm – maybe contest competition. Winner take all. It’s a brutal, unfair world out there for bees. Even so, I cannot explain the electric frenzy that pervades my apiary when robbing is in play. The whole area, far beyond my beeyard, is energized. I feel an odd urge to type my comments here in upper case and bolded. These bees are absolutely nutso. Absolutely.

We are part of the problem

This is one of my guesses. The insanity shown by robbing bees can only be due to the unnatural positioning of numerous colonies near each other. As beekeepers we do that and call the assemblage an “apiary.” There are no natural apiaries in the wild. If I may be blunt, can I say that overall, while great for the beekeeper, I sense that an apiary is not a good thing for bees. It’s where beekeepers concentrate bee diseases, suppress natural swarming, violate brood nest sanctity, entice animal pests, and yes, set the groundwork for massive robbing behavior.

As has become my style, without a shred of original data and without an adequate literature search, I speculate that robbing behavior commonly occurs in nature, but with much less fanfare and commotion. Natural nests are spaced far apart – not just a few meters, and populations are much smaller. Mortal battles are fought, won, and lost. But all of this is out of sight from the prying beekeeper. Resources are reapportioned and a natural nest cavity is made ready for a replacement swarm next spring. Importantly, population dynamics are adjusted to reflect the current carrying capacity of the immediate ecosystem.

I am speculating

Robbing is not simply an inconvenience for beekeepers who are trying to maintain colony numbers. Robbing is a population adjustment strategy that reallocates valuable resources to colonies better suited for seasonal survival. Essentially, the colonies with the best chance for survival get the food reserves of those with a lesser chance of Winter survival.

I speculate even more

In my beeyard, I would guess that as the flowering season comes to an end, some behavioral shift occurs in foragers. Rather than witnessing recruitment dances and learning flowers, foragers seem to broaden their search parameters to anything that smells and tastes of carbohydrates. I would guess, that within my beeyard, there is a general mingling of foragers from colonies that are testing neighboring colonies. If a colony is able to rebuff exploratory robbers, they protect their resources and their scouts possibly find a colony that is having difficulty protecting whatever it has. I suppose I am writing, that during robbing periods, probably all colonies are explored for possible robbing targets, but some are able to resist. Others can’t withstand the onslaught.

But I am at a loss to suggest a way that other robbing foragers are recruited to the newly found weak colony. Ribbands5 said that robbers were using odor cues to find robbing sources and entrances. I don’t doubt that observation, but does it feel a bit inadequate? Why the raging confusion and how are recruits finding the victim source? In the same beeyard, recruitment dances would be generalized. What’s new about the odors. These odors have been there all season long. During robbing periods, what’s different that lets bee sister turn on bee sister so aggressively?

There is one thing . . .

There is one visible characteristic of robbing bees – their erratic, jerky flight. It has long been reported that bees develop that personality because they have been accosted by innumerable guard bees. In some cases, even their thoracic hair has been rubbed away. But just let me ask, “Is it possible that the erratic flight behavior of robbers is a cue for enticing robber recruits to a beleaguered colony?” I am not strongly bonded with my own question. But I am bonded with this notion – there is something different in a beeyard that is attacking and being attacked by robbers. Everywhere this energy, this franticness is exhibited. What bee yard characteristics changed?

I’m not finished…

I am not finished, but my monthly space allocation is filled. In a companion article within a few months, I would like to contribute robbing comments on entrance restrictions, robbing cages, robber behavior and other beekeeper procedures. I hope you don’t mind. Obviously, I have this bee behavior on my mind.

To be crystal clear

I want to be perfectly clear that the citation I posted concerning Scramble and Contest Competition is not my written work. I copied it and then cited it in the URL presented in footnotes. This is the first time I have used a citation that had other URLs embedded. I want to be sure I am crediting the original authors in a proper way.

Thank you.
As always, I appreciate you reading my rambling comments. Readers are a great thing for any writer. Thank you.

Dr. James E. Tew, Emeritus, Faculty, Entomology, The Ohio State University and One Tew Bee, LLC; tewbee2@gmail.com; http://www.onetew.com

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