[Bonus] Short - Hive Debris Analysis with Dr. Dewey Caron

[Bonus] Short - Hive Debris Analysis with Dr. Dewey Caron

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Dr. Dewey Caron: Hi. I'm Dr. Dewey Caron. I come to you from Portland, Oregon. I present another audio podcast on communication, my continuing series of once-monthly Beekeeping Today Shorts Podcast. The topic this month, December, is debris, hive trash. There's a communication from bees to us. For these audio podcasts, I've been discussing communication on three levels, bee scientists to beekeeper, beekeeper to bee, and bee to bee. For this podcast, the scientists are citizen scientists.

I have prepared a book review to be published in the January American Bee Journal of a new book by fellow name of Ray Baxter, titled Bottom-Up Beekeeping: Learning from Debris on the Hive Floor. It's published by Northern Bee Books. Author Baxter lives on a small, organic pesticide-free holding, which is about four acres. It's a family flower farm in the Scottish borders, which is an area of southeast Scotland and northeast England. His book discusses outfitting his AZ hive with a debris board, also called monitoring or sticky board, to capture, and then he's going to analyze hive trash.

How can hive trash communicate anything? Ray Baxter says it well. The idea came from his other hobby of using a metal detector to look for metal in the Scottish countryside. He feels the debris he discovers, the human debris he discovers, help tell a story about how early humans lived. By his extension, he says, "Looking at trash from a beehive can do the same thing to help inform us about what is going on in a beehive." The second citizen scientist I include is Christine Kurtz, known as the Petaluma Bee Lady. She's from the Bay Area of California.

She presents an interesting talk to bee clubs on reading the debris on sticky bottom boards. Let's get started. Do you have a modified bottom board that includes a sticky board? If yes, you probably have used it to determine if or, more likely, how many mites are in your hive. Perhaps, you used it following a mite treatment to confirm the treatment reduced the mite load on a colony. A sticky bottom board suspended beneath a screen permits collecting dead or living mites.

By examining how many mites fall over a certain time period, we can estimate the population level of mites in our colony. Mite fall pre- or during, or post-mite control communicates something about mite numbers. If used to monitor pre-control, they can tell us that maybe mite control is needed. On the other hand, post-mite treatment use, it can communicate that our treatment was or perhaps wasn't effective. Sticky boards are not a particularly precise monitoring tool to help us understand what is happening mite-wise in our colonies.

At one time, we actually counted the mites on the boards. Instead of the tedious counting the number of mites, we might use a three-level estimation of those mite numbers. For example, one, following 24-hour use of a sticky board. If we see none to very, very few mites, we can be reassured that no treatment is needed. Or, if the sticky board is inserted beneath the colony post-treatment, help confirm our treatment was successful. Or two, if we see several mites like about one per hour for the time the sticky board has been in, it can signal we should continue sampling, but perhaps a treatment might not be needed immediately.

Finally, three, if there are a lot of mites, then treatment is likely needed to reduce risk of colony loss. Or, if it is a post-treatment sticky board, the treatment used was probably not as effective as we would have liked. Now, very, very few, and a lot of will be your own individual experience in terms of mite numbers, and you'll need to put your own numbers on that. We don't really have good estimates of those numbers. When we use the sticky board, it has to be figured into our determination.

Materials like oxalic acid have no residual effects, so you can sample post-treatment three days following treatment. However, formic and thymol controls do have a residual effect, so we should wait at least a week before using a sticky board to sample mite numbers post treatment, but the use of sticky boards. Both Christine and Ray help inform us that sticky boards, ie, our debris boards, can be more than a monitoring board for varroa mites. For example, both Ray and Christine find debris boards valuable to monitor the size and position of a colony.

Ray reuses his Bottom-Up Beekeeping boards to monitor the seasonal development of colonies. He both weighed and used heat mapping to determine how much debris accumulated each month. He inserted debris boards in his reports for a 28-day period, which is more than most of us would like to use the debris board. Comparing the differences, for example, in monthly debris amount, his February debris amount increased by 7% from the January amount.

In March, there was a 68% increase in debris. He is demonstrating with this that the amount of debris alone, then is telling what is going on with spring development of his colony. In January, the debris field extended five frames wide, but was only about one-third of the frame length close to the colony entrance, not towards the back of the hive. The 4.55 grams of debris he found measured to about one gram of debris falling from the colony per week.

If we're using it for a two or three-day period, we still could be able to get that estimate of what's happening in our colony. Without a sticky board, this debris would most likely have been clean from a solid bottom board, even though there was very limited bee flight in January, where he is in Scotland. January will have less debris than any other month, but Ray considered it likely to represent an optimum size and amount of hive debris to predict colony survival during those shortest days and the coldest temperatures of his Scottish winter. He was correct.

I'll come back to the Scottish study, but want to initially discuss what Christine is able to communicate with use of a sticky board. She, too, is telling us that the bees can communicate if we capture their hive debris. Things such as debris size, the size of the field, position on a sticky board, for starters, can tell us how big the colony is. We can tell if the colony is weak or strong. When a colony is expanding, worker frass will be lighter in color versus later or during stress when it'll be darker in color. Using that is a key.

If debris field is at one side of the hive, maybe we would move a honey frame from the less-occupied side to the side where they are positioned. In her presentation, she not only reads the debris field, but discusses what it might say to us, something about how we might key a management, but sticky boards also tell a whole lot more. She says the debris field can help us realize there's been a queen event in our colony, keying our need to inspect the colony if we might need to manage that colony.

It is a post-event and is not sensitive enough to predict or show the event as it happens. That's certainly a downfall or one bad issue of sticky boards alone, but it's valuable enough to help us ensure the bees now have a queen right colony by doing our inspection. Moisture, too, showing on the bottom board, whether it's actual puddle water or evidence of a moisture field during winter, can signal the condensing hive is intact because that moisture then comes down the side of the colony.

During spring, it might signal the colony is tipped back, not towards the front. We might want to make that adjustment. Christine and Ray as well point out that the form of brood cappings in the debris field has a big tale to tell. Drone cappings are larger and may be largely intact, or show signs of chewing. Those mean two different things. Chewed worker cappings can signal worker emergence or hygienic removal of worker pupae and, of course, dead brood remains. We won't see the adults because they do

not want to fall through the screen, but many body parts will fall through.

Pollen grains, wax scales, beebread discarded, frass of pests like wax moth, mice, small hive beetle and their poo, that'll fall through. Ants or deceased remains from European foulbrood, chalkbrood are all means of reading a colony by looking at the debris. Christine tells us how to recognize the differences. I certainly recommend her as a bee club speaker. It's a very interesting and informative discussion that she has.

Returning to the book by Ray Baxter of Scotland, it's less a tutorial and more an explanation of how a debris board can reveal hive status. He says reading hive debris enabled him to reduce his hive intervention, minimizing stress and disturbance to the bees and beekeeper. He would see something in the debris. Then he could go into the hive with that objective in mind, not a general inspection. He could do it faster and more easy. I was struck by his introductory comment.

He says, "Before opening a hive, and certainly before moving any colony in my home apiary, the first thing I now do is look at debris. It gives me the clues that I need to make judgements about the location of the colony, its size, the shape of the cluster, the history of the colony, colony activities, pest and parasites, and helps me to make informed hive intervention. Well, some of those things like colony history is a stretch without good records, and he says little in his book about the ID of pests and diseases or its signs that they were there.

You might not actually see the pest or the disease itself on the debris board, but you can tell what might be happening above. Although his book doesn't quite do all this, he does provide a good discussion of how a monthly reading of hive debris tells a story. He gets high school students involved in examining the debris, which he magnifies via cellphone photos. In fact, he credits high school students, in fact, for the reason for his book.

As the students were in his biology class were examining hive debris, they started to ask questions about hive debris. He was doing actually a mite counting activity with them. He was using them with his biology class. He couldn't answer those questions, and then his curiosity was roused, and from that, he did his year-long study resulting in his book Bottom-Up Beekeeping.

He also enlist the help of Master Beekeeper, Christine Coulsting, to examine, stain, and ID pollen grains to tell the story of pollen preference as bee colony. He will learn they rely on stored beebread even when fresh pollen is coming into the colony. He can tell that by what is shown in the pollen grains that Christine stains for him. In an interesting combination of technologies, he uses video recordings of cellular activities. The recordings are of hive activities at a particular cell done earlier by a fellow by the name of Paul Salford.

I have reference to that particular study in the end notes. He uses the video to help determine what the debris might be. It takes help to decipher what some of the tale debris tells. He leaves his debris boards in, as I said, for an entire month, except for the summer months when he has to change them out because of the extensive amount of debris. The bigger picture, he leaves them in because he's interested in the bigger picture of colony development.

He weighs the amount of debris, something not everyone might be able to do, particularly if ants or scavenger beetles are actively foraging on the remains. In addition to body parts of adults, various brood stages, and the pollen that falls from the hive, he use the dust, and both authors use this term, dust, to be a measure of colony size, and what is happening above the board.

If you want to add another dimension to your keeping bees, look down below to the debris of a colony. It tells a tale, one you'll need to validate, but I would guess you might become pretty proficient in a short time. The beekeeper to bee communication is in reverse this time, what we can learn from the bees, what their hive debris or an accumulation of dead bodies within the hive can tell us about them, and what's going on in their hive.

I highlight undertaker bees for the final discussion of bee-to-bee communication in this Beekeeping Todayshort. The undertaker bees are middle age if they are working on getting rid of bodies and cleaning up, or they may be very young bees that are cleaning the debris, reason for some of this dust. Undertaker bees are capable of finding dead comrades in a dark hive in as little as 30 minutes, despite the fact the dead bees haven't yet began to give off their typical colony odor of death.

How do they know a bee is dead? Well, we know living insect continually release compounds called cuticular hydrocarbons or CHCs. These are part of the waxy coating on their exoskeleton, which is critical to prevent them from drying up. In social insects like ants and bees, they are used to recognize fellow hive members. As their bodies cool with death, there is less of these compounds released, understandable.

Yongping, an ecologist at Chinese Academy of Sciences Tropical Botanical Garden, did a series of experiments to determine what might undertaker bees be keying on. He measured the chemical output of dead bees. They did, in fact, produce less of their particular cuticular chemicals with death. Is it both cooling temperature and less cuticular emissions that were of greatest importance or just a cooler body, or less chemicals? When he heated dead bodies, the dead bees were ignored by undertakers.

Their level of chemical output continued because their bodies were still warm. When he washed the bodies of dead bees with hexane, the undertaker bees quickly removed them, demonstrating that it was the reduced chemical output brought on by a cooling body, a neat way to do this determination. Take a calling to get rid of dead bodies. One bee might drag a dead body and then drop it, and the same occurs with the debris.

Another will pick up the task. Another bee might clean and prepare the area where the dead body was found, whether it's brood or adult, removing any remaining pheromones or debris. The entire process is crucial for maintaining the health of a colony, ensuring that disease and those dead bodies don't spread diseases among the living bees. Should we add the tool of examining hive debris to our hive management? Does offer a look at what the bees are doing. Communication we can use to advantage in reducing our hive opening times is it can focus our management.

We can confirm what the debris is saying. Understanding the task of undertaker bees might help provide beekeepers with a better understanding of how bees keep healthy. Communication is a two-way street. We need to understand what they are saying, and we need to better refine what we are asking of them. Thanks for listening. Till we meet again. We'll have the holidays, Christmas and New Year's.

I want to wish all of you a very healthy and a very meaningful holiday. Many of usMany of us will have a break. I'll be seeing some of you at the American Beekeeping Federation in Mobile in the second week of January, the 8th through the 12th. Stop by, say hi with you there. Until the next time, be well.

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