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American Bee Journal

The Classroom – January 2022

By January 17, 2022No Comments
Small Drones

 One of my colonies in Southern California was requeened over a month ago (I requeen in the fall as part of brood break and IPM) and at the time of requeening, about 10% of the colony was comprised of normal sized drones which I consider to be appropriate for this time of year. The hive is a deep and a medium and had been doing well. After requeening, I began to notice an uptick in the number of drones and what is particularly interesting is that the drones were worker sized. I was only noticing brood that appeared to be worker brood.

I caged the new queen for 2 weeks, came back to reassess and found about 40% drones, predominantly small drones (Figure 1). After inspecting, I saw no eggs, but did find an almost fully developed/peanut-sized but EMPTY queen cup and then another queen cell with a larva in it. I removed that new queen and placed her into a nuc to monitor her and see what she does. I then put an older, but appropriately laying, queen into this drone-ridden colony. I had a seasoned beekeeper come and assess the colony and he had never seen smaller, worker-sized drones either.

My questions:

1) Is it possible for small drones to emerge from worker-sized and flat-capped brood cells?

2) Is it likely that the new queen was poorly mated and a drone layer or is she just “new” and working out some laying kinks?

3) Does the origin of a drone (either from laying workers or poorly mated queen) impact its fertility and quality of eggs?

Alana Deegan
California, October

A

These are interesting observations. Thanks for sharing them. It may be a little difficult for me to answer your questions fully as I have a few questions myself. For example, did you requeen with a mated queen you purchased? Or, did you allow the colony to requeen itself naturally? If the latter, it is possible that the new queen did not mate adequately, given you allowed this to happen in September when drone populations naturally begin to decrease. If the queen did not mate adequately (i.e., if not enough drones were available during her mating flight), she would return to the hive, begin laying eggs, and produce a disproportionate number of drones. It is also possible that enough drones were present, but that something anatomical was wrong with the queen, preventing her from mating adequately. Either way, this is one potential reason you are seeing a large number of drones immediately after requeening your colony.

If, though, you requeened with a mated queen you purchased, I would not expect to see so many drones. This is because the queen producer should have caged the queen to sell to you only after he/she observed worker brood being produced in the mating nuc. It would act like a sort of check-and-balance, where the queen should be OK by the time she reaches you. Of course, anything can happen in transit to your house. However, I would guess it would be less likely for you to end up with a drone layer.

Now, on to your specific questions:

1) I have seen queens lay drone eggs into worker cells. I, of course, cannot tell an unfertilized egg from a fertilized one just by looking at it. I only knew it was a drone egg after I saw the developing bee become a drone. Why would this happen? My guess is that the queen would be improperly mated in this instance. She “believes” she is laying a fertilized egg into the worker cell. However, maybe she has no semen to allocate to the egg. Maybe the semen is bad. Maybe something physically is wrong with her to prevent the egg from being fertilized while it is laid. Either way, it results in an unfertilized egg being laid into a worker cell. Drones developing in worker cells are smaller than those that develop in drone cells.

2) I addressed this question in my preamble to my answer here. However, I have seen newly laying queens need some time to work out the kinks, so-to-speak. For example, I have seen new queens lay multiple eggs per cell or lay on stored pollen. This seems to fix itself in a few weeks after egg laying has begun. I do not get worried about it, as it always seems to self-correct.

3) I have read that drones produced by laying workers are fertile and can sire offspring with the queen. They do tend to be smaller than drones produced by queens, but I believe that is a function of them developing in worker-sized cells. You see, laying workers often lay their unfertilized eggs (which is all they can lay) into worker-sized cells.


Is the HBHC varroa management guide outdated?

As a big advocate for mite testing and creating an IPM system for treatment, I encourage folks to visit the Honey Bee Health Coalition website for possible solutions. The “Tools for Varroa Management” document is rather outdated, with a publish date of June 1, 2018 — that was three and a half years ago! Is there nothing new since then? 😟

I recently purchased and installed Apistan in all my colonies and do see a significant mite drop on my bottom boards. The worrisome part is it may be five years until I can use it again, or 2026! In an effort to mix up my treatments, it is rather scary with the limited number of treatment options available moving forward.

One more thing if you have the space: “Where’s the Beef, oops — I mean honey?!” We had a very wet July that brought an abundance of goldenrod, but no one collected much fall (October) honey this year. Really a rather troublesome trend going into winter. I am finding many apiaries with very little honey and sky-high mite loads after treating around Labor Day. Next spring could be deadly.

Randy Katz
Ohio, October

A

First, I am so grateful that you use integrated pest management (IPM) strategies to combat the Varroa in your hives! Kudos to you! I wish more people took the same approach. Second, you are correct. The Honey Bee Health Coalition’s (HBHC) document was last updated in June 2018 (https://honeybeehealthcoalition.org/varroa/). However, I do not think this is a major problem. Honestly, not much has happened on the Varroa control front since that time. Admittedly, it really bothers me to say that. Thus, the information on the HBHC’s website remains the “go to” information related to Varroa control.

The good news is that many scientists are working on Varroa control and I feel that it is a matter of time before we have more options available to us to control this terrible pest. Also, a colleague of mine (Dr. Cameron Jack) at the University of Florida and I just published a very thorough review of research on Varroa control. In it, we review the research literature and report on the efficacy of everything that has been tested to date. This review was published in late 2021 and you can find it here: https://doi.org/10.1093/jisesa/ieab058. The review is a bit academic (it was written for a science audience) but I think you will find it an easy read and full of additional information about Varroa control.

Regarding your question about honey: It really is hard to know. What looks like good weather to us (the wet July you noted) may not be optimal weather for the plants. Plants and nectar flows are fickle things. Nectar production depends on plant physiology, weather, soil, and a number of other factors. Thus, it is not simply good enough to say “the weather was favorable so we should get a lot of honey.” A great summer can favor the growth of goldenrod, but not necessarily favor the production of nectar. I have seen the stars align many times, making me think that I was about to be rolling in the nectar, only to be disappointed by a meager flow. I am sorry it worked out this way for you this year. More troubling is the fact you mention your Varroa counts were so high. Hopefully, your treatment timing and efficacy were appropriate to knock the Varroa populations back to manageable. 


What temperature kills chalkbrood?

Do you know what kinds of temperatures and times it takes to destroy them?

Michael Staddon
West Virginia, September

A

For the benefit of the reader, chalkbrood (Ascosphaera apis) is a fungal pathogen that kills immature honey bees. Its damage is usually limited and it is very unlikely to lead to the death of a colony. My team and I have developed a general document on chalkbrood biology and control. You can find it here: https://edis.ifas.ufl.edu/publication/AA138 (or by Googling “chalkbrood EDIS”). There are several strategies one can use to try to control the disease. They include using hygienic stock, keeping colonies out of low-lying areas, and improving the nutritional health of the colony by feeding the bees.

You are asking specifically about heat treatments for chalkbrood. I found some research that may be useful for answering your question. I will note, though, that I did not find something specific to chalkbrood, but I did find something where heat treatments were tested against another fungus from the same genus (Ascosphaera sp.). The article — Kish, L.P. 1983. The effect of high temperatures on spore germination of Ascosphaera aggregata. Journal of Invertebrate Pathology, 42: 244-248 — can be found here: https://www.sciencedirect.com/science/article/pii/0022201183900666.

The fungus (A. aggregata) tested in this study actually causes chalkbrood in alfalfa leafcutter bees. Go straight to the results and discussion section and you will see some text that discusses temperatures that kill this disease. Interesting, but maybe not too encouraging, is that it took temperatures >100°C (212°F) to kill spores reliably, and then not even that reliably. It is important to remind you that this is a different species of chalkbrood than the one honey bees get. Consequently, the honey bee chalkbrood may die at an entirely different temperature. Nevertheless, this is the only point of reference I have.

I then found a second article that may help as well: Castagnino, G.L.B., Mateos, A., Meana, A., Montego, L., Zamorano Iturralde, L.V., Cutuli De Simón. 2020. Etiology, symptoms and prevention of chalkbrood disease: a literature review. Animal Production and Environment, 21: https://doi.org/10.1590/S1519-9940210332020.

Here is an excerpt that I think is useful:

“Studies led by Starks et al. (2000) showed an additional behavior of the colony in an attempt to reduce the possibility of infection and control of A. apis. Bees seem to recognize the attack of this disease and react to the infestation by producing a temperature increase in the brooding area. According to those authors, this temporary heating aims to reduce mycelial growth and prevent infection of healthy larvae, since A. apis are sensitive and do not develop at temperatures above 35 ºC.”

This is the Starks et al. (2000)
reference: Starks, P.T., Blackie, C.A., Seeley, T.D. 2020. Fever in honeybee colonies. Naturwissenschaften, 87: 229-231.

Nevertheless, this is not likely to be the same temperature one would use to kill chalkbrood. In fact, I suspect it is not sufficient. It just illustrates that colonies may develop “fevers” in response to chalkbrood infection. My guess is that the temperature would need to be closer to what you see for the chalkbrood species that affects leafcutter bees. I am sorry that I cannot be more specific. It looks like this topic needs more research! 


Collecting vs. drying nectar

 I have never seen any information on how bees decide between collecting additional nectar vs. drying down and capping their existing nectar. This fall, I had quite a bit of uncapped nectar that my bees never capped. Some of it I had to dry down myself while some already had a low enough moisture level. Is there something I can do as part of my bee management practices to entice my bees to cap their nectar vs. continuing to deposit more nectar? Maybe I should not add another super until the previous super is a certain percentage capped?

Jim Stellern
Missouri, October

A

Jim: You answered your own question.☺ Let me add some information. First, honey bees are going to keep collecting nectar as long as nectar is available to collect. I have never read that there is some sort of trigger that causes them to switch behaviors to focus exclusively on ripening honey as the nectar flow begins to slow. In a typical setting, forager bees are collecting nectar as hard as they can, while processor bees are processing as hard as they can (i.e., they are processing the nectar in real time). Many nectar flows begin to “taper off” over time, allowing the bees to keep up the processing pace to match the pace of incoming nectar.

There are times, though, that nectar flows just stop. In these instances, the bees run out of the incoming energy needed to complete the ripening/capping process. When this occurs, you can end up with a lot of uncapped nectar, exactly how you describe.

Knowing that this can happen, I have always recommended that beekeepers study their nectar flows and learn to anticipate when the flow will stop. For example, the typical nectar flow lasted about four-six weeks in the area where I first started keeping bees. Thus, I would begin to remove empty supers or frames from … .

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