Info Center

Oh, my. We did not finish all our reports from the Michigan Beekeepers Association Spring 2017 Conference before the year ended and now the Spring 2018 Conference is soon upon us. As part of a desperate sprint, we now cover Dr. Thomas Seeley‘s talk The Bee Colony as an Information Center, based upon information in his book The Wisdom of the Hive.

The landscape around a honeybee colony is dotted with patches of fluctuating resources to be gathered. The resource may be water, pollen, resins for propolis, or nectar for honey but for the rest of this text we shall focus on nectar. Now consider all the variables. Each kind of flower blooms for a different part of the year, provides its nectar at a different time of the day, and its nectar has a different amount of sugariness. All of these are affected by weather. And the patches of flowers can vary in size and distance from the hive. The problem facing the colony is how to efficiently allocate foragers to each useful patch and reallocate as the patch dries up.

The key to the allocation problem is that each forager has a sense of the energetic profitability of a given patch, i.e. the metabolic energy obtainable from the sugar in the gathered nectar compared with the energy expended in gathering it. So a patch of flowers with sugar-rich nectar is preferable to an equidistant patch of sugar-poor flowers. And a patch of flowers nearer the hive is preferable to an identical patch much further away.

We already know how a forager recruits additional foragers and directs them to her patch by waggle-dancing the distance and direction. She also reflects the profitability by the number of circuits she performs.¹ If an uncommitted forager heading out to search for a source encounters a waggling forager on the dance floor near the entrance, she may follow the dancer for five to ten figure-eight circuits, and then proceed to the source being indicated. When there are multiple foragers waggling for different sources, the particular waggler which a recruit first encounters is entirely random but because more circuits are made for better sources, more additional foragers are likely to encounter those wagglers and be recruited for those sources. The result is therefore the desired one that better sources get more foragers.

Furthermore a source that stays constantly profitable for a long part of the day will acquire more foragers than a transient source since a returning forager is likelier to waggle on each return to the hive. Foragers can thus be acquired in a flash or slowly and steadily.

An uncommitted forager who does not encounter a dancer or is not in a following mood will head out to possibly find her own patch. This is how newly blooming patches are discovered and by the process described above they will acquire their appropriate quantity of foragers from the uncommitted. Very few foragers will switch from one patch to another, even if that one is more profitable than the one they are currently working. But once a patch becomes unprofitable its foragers will quit although it takes a few days of unprofitability for them to entirely abandon the patch.

Dr. Seeley learned all this by direct observation of the bees during his experiments at the Cranberry Lake Bio Station in Adirondack Park, where the nearest natural forage is twelve miles away. The only honeybees in the park were therefore the ones he brought in his two-frame observation hive and their only forage was whatever he provided. After tediously labeling all four thousand bees (a two day job for four people) in his observation hive, he and his assistants would set out sugar syrup feeders, systematically varying sugar concentrations, locations, etc. while logging which particular individually numbered bees arrived at which feeder and which ones danced. The straightforward tedium to which much of science owes it advances. We are still gobsmacked at the thought of labeling four thousand bees. The Wisdom of the Hive describes the experiments in detail and clarifies (perhaps even corrects) the processes we have described.

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¹The most enthusiastic dancer Dr. Seeley observed was a water forager who danced for fifteen minutes making 346 circuits. She clearly thought the source was profitable although not a source of energy as we have been discussing.

 

Plastic Foundation: Good for Beekeepers? Good for Bees?

When we first mentioned that we would be posting detailed follow-ups of the talks we attended at the Michigan Beekeepers Association Spring 2017 Conference, there was a particular request from a reader for a report on Dr. Seeley’s presentation on plastic foundation, Plastic Foundation: Good for Beekeepers? Good for Bees?, and the interesting thing we non-users learned. Months later we finally present that report.

Plastic foundation is food grade plastic covered in a very thin layer of beeswax¹. It is available in two forms, as sheets to be inserted into wooden frames just as wax foundation is and as complete one-piece plastic frame including foundation. The general conclusion is that it has advantages for the beekeeper.

• Frame assembly is made simpler, especially if already part of a one-piece frame.
• The plastic back makes strong combs that do not blow out in a centrifugal extractor.
• It is better for pre-supering.² Practiced in apiaries that are hard to visit frequently, this is the procedure of adding supers of undrawn comb far in advance of a nectar flow. Wax foundation thus used gets dry and nibbled.

But Dr. Seeley had questions about disadvantages for the bees.

• Does it hinder comb building?
• Does it reduce honey production?
• Does it interfere with waggle dancing?

The answer to the first two is ‘yes, but there is a fix’, the first part of which is to paint a thicker layer of beeswax on the plastic sheet³. Dr. Seeley suggests using disposable foam brushes. That may suffice but one can also try to establish ideal conditions for comb building: a heavy nectar flow and hive full of brood and nectar. The middle-aged bees, which are the nectar-receivers and wax-producers, will be strongly motivated to draw out comb to make room for the incoming flood.

That leaves the question of whether or not it is a fully suitable substrate for waggling. And here comes the information we found so interesting, if only because of the many hours spent so long ago surrounded by electronics equipment in physics labs . The comb consists of relatively thin cell walls rising from the foundation and having a thicker rim at the top. A waggle-dancing bee shakes this rim to attract followers, producing vibrations centering around two frequencies, 15 Hz with its body and 250 Hz with its wings. Followers of the dance detect vibrations in air and through the comb with the subgenual organ in each leg, seemingly over a greater distance on open comb than on closed comb.

In one of his few experiments not involving watching individually marked bees in an observation hive placed in a contrived environment, Dr. Seeley used an oscillator in a lab to find that comb on plastic foundation dampens the 250 Hz signal but not the 15 Hz component.⁴ But then he returned to his habitual tricks to observe in the field that there was no difference in recruiting effectiveness for any of wax foundation, plastic foundation in wooden frame, and one-piece plastic frame with foundation.

One question raised by the audience that was not investigated was whether the plastic outgassed significantly to harm the bees or build up in the wax. But then Dr. Seeley’s focus is honeybee communication rather than general health and that investigation would have required an entirely different array of laboratory equipment.

In conclusion plastic foundation has advantages for the beekeeper and, even with different acoustic properties than wax, no disadvantages for the bees if the beekeeper makes an effort to get them to draw comb upon it.

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¹Very, very thin. Jokes were made about the nearly monomolecular, almost homeopathic thinness of the wax coating.
²An audience member pointed this out.
³The same audience member pointed out that a version with thicker wax coating is available.
⁴It is common for higher frequencies to be more attenuated than lower due to acoustic heating of the medium.

 

MBA Spring 2017 Reports To Come … Eventually

Last weekend, we attended the Michigan Beekeepers Association Spring 2017 Conference. The main attraction this year was Dr. Thomas Seeley, famous for research into honey bee behavior, who gave four talks over the two days. Will we be able to post a report on each of them before the year is up? Probably just barely.

The Bee Colony as an Information Center This talk described how a colony efficiently deploys and redistributes foragers to nectar sources in numbers related to the changing quality of the source. We serendipitously discovered that the material is also in his book The Wisdom of the Hive, which we bought at the conference. The diagrams are so much better than our hastily scrawled sketches. Plastic Foundation: Good for Beekeepers? Good for Bees? We attended in spite of using no foundation of any kind, certain that we would learn something interesting about the bees. We did but you will have to wait. The Bee Colony as a Honey Factory This was a repeat of the talk from a SEMBA conference in 2013 and we have already written about it. So we need report on only three talks before the year ends. We may just make it. Capturing Swarms with Bait Hives After describing his experiments to determine what kind of home the bees themselves prefer, also found in the popular HoneyBee Democracy, he presented the results, rather well-known by now, and gave practical advice on exploiting those results to successfully catch swarms.

We also attended some non-Seeley presentations, which may or may not result in blog posts.

Plan for Mites by Dr. Meghan Milbrath. The message, that we are in a varroa epidemic and whistling past the beeyard will not be helpful, is much the same as her previous talks but the tone has gotten firmer. If one will not be a responsible bee-keeper then one will not be merely a bee-haver but a bee-serial-killer. She has thoughtfully provided the text of her talk on this Michigan Pollinator Initiative web page.

Beekeeping in Uganda by Sarah Scott. Currently conducting field research for the United States Geological Survey this talk is from her time studying honeybee health in Uganda. The saddest thing we learned was that as the illegal distillers of sugarcane attempt to improve their fortunes they are inadvertantly ruining that of beekeepers. Bees drown in the open fermenters full of sweet sugarcane liquid.

Essential BeekeepER First Aid by Dr. Tyler Andre. The capitalized ER is deliberate to nod at the speaker being an Emergency Room resident.

The Benefits of Splits and How to Make Them by Nathan Snyder. This presentation contrasted methods used in his own hobby apiary and in the larger commercial apiaries for which he has worked.

And so to start writing.

 

Honey Factory

This is a first. Each time we return from a SEMBA meeting we are excited by some new information but also too exhausted to report anything about it until sufficient time passes that the impulse dies and, oh, it is nearly time for next year’s meeting. A similar phenomenon occurs on shorter timescales with the monthly Ann Arbor Backyard Beekeepers meetings. Yet somehow this time we have managed to write about it not even three weeks later!

We were rather put off by the title of this year’s keynote address, “The Bee Hive as a Honey Factory”, bringing to mind industrialized manipulations to maximize honey crop with disregard of the welfare of the exploited bees. Foolishly we had failed to notice that the speaker was Dr. Thomas Seeley, a Professor in the Department of Neurobiology and Behavior at Cornell University, beekeeper of many years, and author of HoneyBee Democracy. Thus the talk was a fascinating presentation of the ways a colony’s collective decisions arise from communication signals by its individual bees.

Coordination of the Gathering and Receiving of Nectar (click to enlarge)

First of all, the foragers that return with nectar do not themselves store it in the comb. There are receiver bees in the hive for that job. The forager must find such a receiver and transfer her load before returning to her foraging. Efficient nectar gathering and saving therefore requires a coordination of these work loops so that optimally there are neither receivers standing idle waiting for foragers nor foragers vainly searching for a receiver. The coordinating mechanism is dancing foragers.

Waggle Dance – the angle from vertical indicates direction of the source from the sun; the duration of the waggle run signifies the distance.

Even non-beekeepers know a bit about the waggle dance as a way foragers tell the hive where nectar can be found. Deciphered by Karl von Frisch in the 1940s, the dancer shakes her booty in a way that encodes the direction, distance, and quality of the nectar source. Sometimes misrepresented as mere announcement of discovery, it is useful to think of this dance as not a notification but rather a recruiting of more foragers.

Frisch was unable to decipher the much less well-known tremble dance, perhaps because this dance seems to lack any structure. Unlike the figure-eight of the waggle dance, the trembling forager seems to wander through the hive at random. One imagines the poor ethologist in the position of someone familiar with the structure of the minuet, waltz, or even the pony observing the free-form terpsichorean paroxysms of modern dance clubs for he eventually concluded that it was simply some meaningless tremens but it is actually a recruiting of more receivers.

The choice of which dance to perform if any at all depends upons how long it took for the forager to find a receiver. If a receiver was found very quickly then the number of active receivers could support more foragers and so she waggle dances to enlist more. If it took a very long time to find a receiver then laden foragers are wandering the hive when they could be out gathering and she tremble dances to enlist more receivers. If the time was of the correct length then delivery and receipt of nectar processes are in balance and she may straightaway return to foraging.

The last relevant signal is the bump and beep. A forager who decides more receivers are needed may notice a previous forager waggling away. Recruiting more foragers would be counterproductive so she tells the other forager to stop by head butting and making a particular kind of beeping noise.

There was much more to the talk, some of which is in HoneyBee Democracy, including what sort of cavities bees prefer for occupancy, how a swarm chooses a home, and descriptions of how all these things were determined by observers and experimenters. It was a splendidly informative way to begin a conference.