Contents
Distance that Employee Bees will Waft 1
Impact of Distance upon Bee Waft 4
Hive-to-Hive Variation in Captured Tags 7
Mite Immigration: Result of the Stickyboard Counts. 10
Cumulative Mite Immigration. 11
A Learn about on Bee and Mite Waft:
Phase 4
Randy Oliver
ScientificBeekeeping.com
First printed in ABJ Would possibly 2023
The consequences that I introduced final month urged that in all probability 5-10% of our tagged bees drifted to different colonies in the community, and (strangely) that drifting didn’t seem to be essentially correlated with both the stage of mite infestation of the bees, nor the timing of cave in. So let’s transfer directly to what else we discovered.
I left off final month with quite a few yet-unanswered questions. So let’s get started off with considered one of nice pastime to beekeepers:
Distance that Employee Bees will Waft
Query: How a ways from collapsing colonies will bees (and hitchhiking mites) float?
As a way to solution this query, we had positioned magnetic front traps on 24 Receiver hives at distances from 15 ft to a few miles from the Donor hives (Determine 1).
Fig 1 The approximate format of the Receiver hives. The Donor hives had been on the heart of the golden megastar. Drifted tag restoration is indicated within the inexperienced bins. We recovered nearly all of the tags from our House backyard, but additionally 13 tags (6% of the entire) from two of the outyards.
Even though we began tagging bees at the seventeenth of September, we didn’t get well our first tag in an outyard (a part mile far-off) till 9 days later (Determine 2).
Fig. 2 Bingo ― our first tag in a far off outyard! It wasn’t till 9 days when we initiated tagging that we recovered the primary tag from an outyard (the white dot on the tip of my thumb) — evidence that bees can certainly float over a large community. The arrow signifies the course to the Donor colony again house ― a part mile far-off (and over two valleys). In spite of striking magnetic traps on handiest 3 of the 30 hives on this outyard, we nonetheless recovered, over the process the learn about, 11 tags from drifted bees (from seven other Donor colonies), indicating that really extensive employee float at this distance was once “standard.”
How really extensive? Since we handiest tagged kind of one bee out of 30 employees in each and every Donor hive, and positioned magnetic traps on handiest 3 hives out of thirty at this backyard, we will extrapolate that the ones 11 recovered tags counsel {that a} general of kind of 3000 bees drifted from the 11 Donor colonies to this backyard a part mile far-off!
Remember that this experiment was once run in a space with numerous landscapes, plants, and elevations (Determine 3), so we don’t understand how this discovering would follow to flatlands.
Fig. 3 This map presentations the panorama between the Donor colonies at my position on the most sensible, and our apiary to the south the place we recovered the tags from 11 drifted bees. The street is on the backside of a valley. We had been amazed by means of the quantity of float to this location, no longer handiest because of the gap, but additionally as it concerned flight over wooded area, two valleys, throughout a hayfield, and into an apiary hidden by means of oak wooded area. Why the heck would such a lot of bees float to atypical colonies up to now away?
We additionally recovered any other two tags from 3 hives (out of thirty), the ones hives had been well-hidden by means of timber and a fence, at a distance a complete mile in the other way, indicating that there was once considerable bee float happening even at that distance. This leads us to any other query:
Impact of Distance upon Bee Waft
Query: How does the float of bees to close by hives examine to that to these extra far-off?
Determine 4 presentations moderate tag restoration according to Receiver hive by means of distance from the Donors.
Fig. 4 What truly stunned us was once how nice the float was once to the hives 500 ft far-off, in comparison to the ones in undeniable sight of the Donors at 60 ft. Now not handiest had been the ones Receivers positioned uphill, there have been a number of structures, timber, and different stumbling blocks and landmarks between them and the Donors.
The above distribution of drifting bees was once utterly sudden, and definitely wouldn’t be anticipated by accident. Have a look again at Determine 1 — for each and every distance from the Donors, the outside house of the panorama will increase by means of the sq. of the radius [[1]]. Thus the chance of a drifted bee randomly touchdown close to any other hive decreases exponentially with distance.
So I ran some calculations, based totally upon two assumptions: (1) since there was once minimum nectar waft going down right through this period of time, there can be no reason why to be expecting {that a} drifted bee can be much more likely to fly close to any specific Receiver hive location than any other, and (2) the possibly false assumption (since we all know that employees have a tendency to forage as just about their hive as conceivable) {that a} drifted bee can be as more likely to land a mile from its hive as it might to land extra carefully (which might underestimate the calculated disparity between the anticipated and noticed values (Desk 1 and Determine 5).
Fig. 5 The blue plot signifies the chance by accident of a drifted bee touchdown inside of 10 ft of a Receiver hive relative to the outside house of the panorama encompassed by means of that distance (the chance temporarily approaches 0). The purple plot is our precise % tag restoration. The boldface numbers point out the proportional expand over what can be anticipated by accident. As defined above, the fold-increase numbers are most likely underestimations.
Our knowledge obviously point out that the drifted bees didn’t simply randomly finish up in far-off hives by accident — one thing obviously drew them to these hives.
Interpretation: The above was once probably the most sudden (and engaging) discovering (to me): that our tagged bees drifted into extra far-off hives at a fee disproportionally a ways more than anticipated by accident. Each clinical literature and box observations point out that honey bees show off remarkably correct navigation and homing talent. I will know the way a returning bee may float to an adjoining hive, however why would the velocity of float to far-off hives be so disproportionately prime?
Possibly foragers are much more likely to get misplaced, disoriented, or at a loss for words as they get farther from their properties. May just it were as a result of right through my learn about — because of little nectar or pollen waft going down — that the foragers had been exploring farther from their hives than they’d were had close by forage been extra ample? One explanatory speculation can be that that after a bee will get disoriented, that it merely flies upwind towards the odor of the closest hive. Or are some foragers merely not able to withstand the alluring odor of any other colony? This can be a query crying for extra analysis — which might be simple to do with those magnetic tags and traps.
The above dialogue brings up any other considered one of our questions:
Hive-to-hive Variation in Captured Tags
Query: Are some colonies extra (or much less) sexy to drifting bees (and thus mites) than others?
This topic was once raised on this very magazine transparent again in 1932 by means of George King [[2]], who described the result of his learn about (on the College of Illinois) at the drifting of marked bees:
It was once discovered that the quantity of drifting between colonies was once incessantly over 30 % of the entire collection of bees. [His test colonies were in a row, spaced 4-8 feet apart].
He famous that:
There are components rather then the gap of colonies from each and every different which affect drifting.
King wrote that:
Regularly one colony seems to outyield different colonies close to it, and so the queen in it’s decided on as an appropriate mom to requeen the apiary. She will have to be a decision queen if she is chargeable for the additional appearing made by means of her colony. Then again, if employees reared in neighboring colonies have drifted into her colony with out an equivalent float again into them, the queen can’t be credited with the effects proven.
Dr. Jerry Bromenshenk (pers comm), the use of front counters, additionally discovered that some colonies received energy because of constantly having extra bees getting into than exiting — indicating that drifters had been regularly including to the populations of a few hives in an apiary (the opposite was once additionally true). Jay [[3]] and Pfeiffer [[4]] discovered that with hives positioned in a row, the ones on the ends might pick out up further float, however Bromenshenk discovered that it may be unbiased of relative placement.
King’s concluding remarks had been prophetic:
There are such a lot of issues to imagine in beekeeping of which so little is understood that additional info is definitely fascinating. One of the vital issues which is able to endure substantial investigation is drifting.
90-one years later, I couldn’t have mentioned it higher myself! Now again to our findings …
In Determine 6 we will see that one of the crucial house backyard Receivers gave the impression to be extra (or much less) sexy to drifting bees (I’m no longer transparent whether or not guarding habits made a distinction, since a drifted bee handiest had to make it to the doorway to be snagged by means of the magnetic entice).
Fig. 6 I’ve color-coded the hives by means of their distances from the Donor hives (the nonmagnetic seize from the Donor hives isn’t proven). Observe that during any distance workforce, some colonies gave the impression to be extra (or much less) sexy to drifting bees than others (regardless of all hives being identically sized and coloured, most commonly of the similar bee inventory, and of kind of equivalent energy).
So how about my haphazard alternatives for the 3 hives to which I carried out traps out of the thirty in each and every outyard? I do not know as to whether or not they had been personally sexy or unattractive to drifting bees ― so they will have over- or underestimated moderate float to these yards.
The query then arises as as to whether colonies that draw in or permit extra ingress of drifting bees additionally endure extra a great deal from mite immigration. So let’s transfer directly to what we discovered concerning the affiliation between employee float and mite immigration:
Validating our Technique
As a way to quantify mite immigration, we needed to take care of Receiver colonies that had been just about freed from mites (and mite replica). We did this by means of use of persistent miticide remedy. We began taking formal stickyboard counts on 17 September — later than I’d was hoping for, since we had been already seeing really extensive mite drop in our initial exams. This made me ponder whether our Receiver colonies had been truly mite loose. So we carried out alcohol washes on two dates to substantiate (Desk 2).
In spite of all colonies nonetheless displaying very low infestation charges of the grownup bees (which will have been from recently-immigrated mites), I used to be nonetheless curious whether or not R5 and R7, which exhibited constantly prime sticky counts, had been producing their very own mites. So on 17 October I dissected 100 cells of white-eyed pupae to pre-emerging adults from R5 (Determine 7). There have been 0 mites. R7 was once utterly missing sealed brood — no larvae had been previous 3rd instar, indicating that the Carniolan colony had close down brood rearing a while in the past, handiest to restart a couple of days sooner than inspection (so no mites will have been within the brood). Those findings strongly supported that their stickyboard counts had been curiously due only or no less than basically to incoming mites.
Fig. 7 I didn’t in finding proof of a unmarried mite within the hundred pupal cells that I dissected, confirming that very little mite replica was once going down within the colony with the absolute best day by day mite drop.
Box analysis be aware: It’s essential for a researcher to repeatedly query no longer handiest their interpretation in their knowledge, but additionally the validity in their technique.
Nonetheless, I wondered whether or not, regardless of my repeated 0 mite wash counts, brood dissections, and the overall November wet days take a look at, whether or not our stickyboard counts actually mirrored mite immigration, versus surreptitious mite replica inside the colony. So in 2019 I replicated treating receiver colonies and taking stickyboard counts from six colonies in the similar backyard over kind of the similar period of time. This time the elements was once much more useful! Check out Determine 8.
Fig. 8 This time there have been 3 flight-suppressing climate occasions, which once more showed that the mite drops in handled Receiver hives was once because of drifting bees.
O.Okay., now that I’m ok with our technique and information, let’s see what we discovered.
Mite Immigration: Result of the Stickyboard Counts
The collapsing Donor colonies had been rife with mites at the employees (Determine 9).
Fig. 9 Via 15 October a number of Donor colonies had been obviously collapsing — maximum with a number of marked bees nonetheless at the combs. Observe the prime varroa infestation fee on this picture from a collapsing colony — right here you’ll be able to see two employees with a mite on their again (take into account that maximum mites journey at the abdominal).
So let’s solution some extra of our questions, beginning with two that we will solution on the identical time:
Cumulative Mite Immigration
Query 1: How many mites in truth immigrated into our Receiver hives in past due summer season and fall?
Query 2: Do all colonies endure similarly from mite immigration?
We recorded semi-weekly stickyboard counts from the Receiver hives, and counted a complete of just about 3000 mites, nearly all of that have been most likely immigrants. So let’s check out the cumulative counts (Determine 10).
Fig. 10 Receivers R5 and R6 (at kind of 60 ft from the Donors) had the absolute best immigration totals, while the adjoining R3 and R4 had the bottom ― pass determine! And it’s transparent that the quantity of mite immigration differed a great deal from hive to hive, irrespective of placement. Total, the Receiver colonies won a median of 245 apparently-immigrated mites over this period of time (R5 were given over 500).
Sensible utility: At the identical belongings, with 9 collapsing colonies, there was once massive hive-to-hive variation within the collection of mites that hitchhiked into Receivers as much as 550 ft far-off. Unusually, the quantity of immigration wasn’t associated with their proximity to the collapsing hives.
The 160 tagged bees that we all know drifted to the 12 House Receiver hives would possibly not look like a big quantity, however take into account that we handiest tagged an estimated 1/thirtieth of the entire collection of employees in each and every donor hive (which began at moderate cluster sizes of more than 9 frames coated with bees), after which recovered tags from handiest 2.7% of the ones. So we will extrapolate that on moderate, each and every House Receiver had a median of 360 Donor bees float into it, nearly all of which might were untagged.
Sensible utility: Even with 9 colonies collapsing from varroa within the House backyard, the above calculated quantity of heavily-infested drifting bees may just handiest account for a median of about 70 out of the typical 245 mites that confirmed up at the stickyboards. This can be a nagging query to me — did maximum of the ones mites come from in different places, or did our restoration of tagged bees no longer absolutely constitute the real stage of bee (and mite) float from the Donors that in truth came about? We might be able to solution this with a deeper research of our knowledge.
Subsequent Month
Within the subsequent installment, we’ll take a deeper glance into our knowledge, and deal with our ultimate questions:
Query: Is mite immigration stable or episodic?
Query: How carefully did mite immigration correlate with the drifting of tagged bees?
Query: Did mite immigration correlate with robbing at my location?
Acknowledgements
Thank you once more to my helpers Brion and Alice Dunbar, Sandy Honigsberg, Anna Mudd, and Brooke Molina.
Citations and Notes
[1] Floor house = 
[2] King, GE (1932) Drifting bees might make manufacturing data of little worth. Am. Bee J. 72: 141-142.
[3] Jay, SC (1969). Drifting honeybees in business apiaries v. Impact of drifting on honey manufacturing. Magazine of Apicultural Analysis 8(1): 13-17.
[4] Pfeiffer, Okay & Okay Crailsheim (1998) Drifting of honeybees. Insectes Sociaux 45: 151-167.