Q: Queen influence over hive defensiveness
I recently requeened two defensive colonies with Pol-line queens. Placing them in these colonies usually takes me 10 days to secure acceptance. What I have noticed is that within two days of a queen cage placed in these colonies, their temperament completely changes. The queens are still in their cages. Are these new queens producing a pheromone different than their original queen?
Thomas Sipprell
Florida, August
A
I have received this question in the past, and I could not answer it that time either. 😊 It was from another Florida beekeeper (probably reading my response here) who made the same point. We all know that requeening a defensive colony can reduce that colony’s defense response. After all, replacing the old queen that confers heightened defensive traits to her progeny with a queen from a gentler stock would result in a colony that becomes less defensive as the new queen’s offspring replace those of the old queen. Yet, this is not what you and the other beekeeper are asking. You are making the point that merely putting a new, caged queen into the defensive colony was enough to cause the bees to get calmer within a day or two.
I have looked for an answer to this question at least four or five times in the past and I cannot find a clear explanation for your observation. Honey bee queens use the same pheromones, so it is difficult for me to imagine that the new queen is producing a new pheromone that would lead to this drastic change in behavior. Of course, each queen could produce different amounts or proportions of the same pheromones, with these giving each queen its unique bouquet of pheromones. However, this is only speculation on my part.
I did find a few manuscripts in which the investigators noted the influence of queen pheromones on colony defensiveness. See the following manuscripts as examples:
Morgane, N., Reinhard, J., Giurfa, M. (2016) The defensive response of the honeybee Apis mellifera. Journal of Experimental Biology, 219(22): 3505 – 3517. https://doi.org/10.1242/jeb.143016 (Go to the last paragraph under the section entitled Defense of the hive entrance and subsection Intra-specific defense.)
Gervan, N.L., Winston, M.L., Higo, H.A., Hoover, S.E.R. (2005) The effects of honey bee (Apis mellifera) queen mandibular pheromone on colony defensive behaviour. Journal of Apicultural Research, 44(4), 175–179. https://doi.org/10.1080/00218839.2005.11101175=
However, both studies highlight how the presence or absence of queen pheromones influences a colony’s defensive response, not how a particular queen causes that response to go up or down. It is certainly possible that the new queen produces more or less of a particular pheromone than the old queen produced, thus causing the colony to elicit a different defensive response when encountering the new queen. Maybe this is what is happening. Even still, I could not find support for this in the literature.
Q: Varroa monitoring methods
Last summer, fall and winter, I got force educated on viruses and mites. I was keeping sick bees since sometime in June and only caught on to the fact when they started crashing in October. I am rather thick headed by nature so that is simply what it takes.
In the eleventh hour (eleventh month literally), I bought a nice
InstantVap 18V vaporizer and set about to rescue what remained. In the much reading I did, I noticed on [Dadant’s oxalic acid (OA) vaporization fact sheet] that you could monitor mites using the vaporizer. After vaporizing some pitifully sick colonies and being thoroughly impressed with the mite drops, surprising rallies in bee health, and how little collateral damage a treatment does (the worst mortality I have seen directly caused by the treatment has been about a dozen bees), I said, “Why would I do anything else to check mite levels!”
Here and there, including your reply to Max Lindegger of Australia in the August ABJ, there are hints that this is a method of actually monitoring mite levels, but I have not come across much information about this method of checking for mites.
This has all been good, and that is how I am doing it, but the one frustrating factor is the absence of data answering the question: What is the threshold I should be concerned enough to be treating at? In the round of monitoring vaporizations I did this week, the worst sticky board had 6 mites on it. About half had none. Most of the colonies were medium-strength colonies (one deep really full of bees) so that indicates a typical mite wash between 0 and 1, correct? My first round of doing this, a month ago, gave me sticky-board counts between 0 and 2 mites and I struggled to believe that, so I pulled drone brood until I was cross-eyed but failed to find mites that way either. We are having our best summer since I have been keeping bees, and my goal is to do my part to keep it that way.
Jered Lepp
New York, August
A
I am glad to hear that you are thinking about how best to monitor Varroa populations in your colonies. These mites, and the viruses they carry, remain a significant threat to colony health. I want to take a second to discuss what is meant by the term “monitoring” to set the stage for my answer. As you know, monitoring is not simply determining the presence or absence of Varroa in a hive. After all, most (all?) colonies in the U.S. have mites. The real goal of monitoring is to turn a mite number we obtain in a sample of bees/brood into an actionable management outcome. You allude to this when you ask: “What is the threshold I should be concerned enough to be treating at?” You recognize that the point of monitoring is to provide a mite number you compare to an established threshold. If your number meets or exceeds that threshold, you need to treat the colony for Varroa. If your mite number remains below the threshold, treatment is not warranted. For the sake of our discussion, many recognize a standard economic threshold to be three mites per one hundred adult honey bees. You can determine this mite-to-bee ratio using alcohol washes, sugar shakes, soap washes, or other standard techniques. Check out the Honey Bee Health Coalition’s Varroa Management website for information on sampling techniques (https://honeybeehealthcoalition.org/resources/varroa-management/).
I am only aware of economic thresholds calculated for washes of adult bees (3 mites/100 adult bees) and sticky screens (~60 mites/day of natural mite fall) placed on the bottom boards in untreated hives. In fact, economic thresholds of any type are usually calculated on untreated individuals. Thus, as far as I am aware, there are no calculated thresholds associated with colonies treated with OA in the manner you discuss. My only advice is to conduct standard sampling methods (alcohol wash, as an example) to see if you are at 3 mites/100 adult bees.
The reason thresholds are calculated for untreated colonies is that mite response to treatment is too variable to use to calculate an economic threshold. For example, you are hoping to correlate mite fall after OA treatment with an actionable threshold in your colonies. However, what if most of the mites were on the adult bees? What if most were in the brood? What if you did not measure the OA accurately when you treated the hive? There are several reasons that administration of OA via vaporization could produce varied knockdown of mites, leading to a number that may be actionably misleading. It is tempting to say that your results (getting very few mites on a sticky screen after an OA treatment) suggest low mite numbers in your hives, but I would still conduct alcohol washes to see if their results match what you see after OA vaporization. I am happy to hear that this is the best summer you have had keeping bees. I hope this continues for you well into the future! …
