Synopsis: How far does a queen fly to mate? Research utilizing RFID-tagged queens are offering insights into the frequency, length and temperature dependence of queen mating flights … all of which have sensible implications for beekeeping.
Introduction
Though it tends to be a fairly poor subject of dialog at dinner events , I’m getting more and more within the mating biology of honey bees. That is a necessary a part of the life cycle of our bees, and one which has been – and continues to be – effectively studied.
Right here’s one I made earlier …
Once I lived within the Midlands there have been a seemingly limitless provide of bees within the space. Beebase reported that there have been about 200 different apiaries inside 10 km of my important apiary. Assuming a mean of 5 hives per apiary , and ignoring any wild or feral colonies, that’s 1000 hives producing drones with which the queen may mate .
In fact, it’s not fairly that easy, however bear with me.
In Fife, on the east coast of Scotland, my apiaries are in areas with about 35-40 different apiaries inside 10 km, so – utilizing equally dodgy maths – maybe 200 hives.
However, bees are in apparently plentiful provide.
What do I imply by ‘plentiful’?
As a beekeeper, the 2 important methods – aside from Beebase or by bodily looking for them – I can choose the numbers of bees within the surroundings are, the:
- success of my bait hives in attracting swarms , and
- the benefit with which my queens get mated
If I catch plenty of swarms and a excessive proportion of my queens mate efficiently then there should be loads of bees about.
Apiary density
I used to be intending to start out this publish with a dialogue of the evenness or in any other case of the distribution of apiaries throughout the Beebase-defined 10 km radius.
Nevertheless, it seems that my maths usually are not adequate to plot a very even distribution of hives/apiaries . Anyway, frequent sense dictates that apiaries usually are not evenly distributed … so let’s as a substitute simply think about the variety of hives per sq. kilometre inside that Beebase 10 km boundary.
Neighbouring apiaries, hive density and queen mating distances (see textual content for particulars)
Within the diagram above the enclosing black circle signifies the realm inside which Beebase reviews ‘neighbouring’ (i.e. inside 10 km) apiaries. Inside that I’ve proven simply 4 of the 314 one km2 blocks (in blue). On common, within the Midlands every of those would include ~3.2 managed hives . In Fife, there can be – on common once more – about 5 occasions fewer hives per blue sq..
A number of research recommend that drones fly comparatively brief distances from the hive to the drone congregation areas (DCA) the place they ‘loiter with intent’ (of discovering a virgin queen to mate with). I’ve mentioned the usage of harmonic radar monitoring research to determine these places.
So, what number of of those hives are literally throughout the vary of a queen on a mating flight?
The place do you go to my pretty?
I posed the query What number of of those hives … ? as we don’t know the place the precise DCAs are.
The radar mapping research recognized a number of inside a couple of hundred metres of three drone producing colonies, so it appears cheap to easily assume the DCAs are close to the hives, and we all know the typical density of those.
Harmonic radar monitoring of tagged queens visiting DCAs was not profitable. It’s a brief vary method, and the queen is understood to generally fly lengthy distances to go to DCAs.
I’ve mentioned among the research used to find out these long-distance virgin queen flights, however summarise them once more right here:
- In research virtually 90 years in the past, Klatt noticed profitable mating on an remoted peninsula when the queen and drones had been 6.3 miles (10.1 km) aside
- Within the mid-50’s Peer demonstrated matings may happen when the queen and drones had been 10.1 miles (>16 km) aside
- Jensen demonstrated mating when the queen and drones had been 9.3 miles (15 km) aside
In fact, in all these research it was not decided whether or not the queen and drones flew related distances to the DCA. Since we all know that drones most likely fly comparatively brief distances it’s seemingly that the queen does nearly all of the leg wing-work.
Ignore the outliers
The Peer research confirmed that, though mating may happen when drones and queens had been very broadly separated, there was an inverse relationship between mating success and distance.
Simply because 5% of queens can mate following mixed flight distances of 15 km doesn’t imply that’s the gap they normally journey.
Truly, if solely 5% of queens get mated at that distance then we will be fairly positive they normally fly a lot shorter distances.
Happily, Jensen did a extra thorough evaluation of this and confirmed that 90% of all matings occurred inside 4.6 miles (7.4 km) and 50% inside 1.5 miles (2.4 km).
And people are the 50% and 90% circles plotted on the diagram above, encompassing an space of 18 km2 and 174 km2 respectively.
Or, to precise that space in potential drone donor colonies, 58 or 548 respectively within the Midlands, with a hive density of three.2/km2.
So, in areas with cheap densities of bees, realizing nearly all of queens fly not more than 7.4 km, there are probably a whole lot of colonies producing drones that the queen may mate with.
All of which is a rambling introduction to queen mating distances utilizing a special strategy.
Slightly than work out how far she flies, what occurs if we measure how lengthy she takes?
If we all know how briskly the queen can fly we are able to once more calculate distances and the variety of potential drone producing colonies inside vary.
Time and climate dependence
However there are further benefits of queen mating flight length.
If we are able to do it precisely we are able to additionally decide the:
- time of day when most mating flights happen,
- affect of the climate on the length and frequency of queen mating flights,
- variety of orientation and mating flights the queen takes.
And admittedly, as a sensible beekeeper, I’m way more within the first two of those than I’m within the absolute distance she flies for her dalliances.
In an space well-populated with hives, understanding when the queen is more likely to be away on a mating flight will assist me keep away from interrupting her return, and figuring out when she is more likely to begin laying.
However, as a scientist, I’m additionally actually within the third level as there may be some attention-grabbing current work to recommend that drones attempt to limit queens taking a number of mating flights .
Heidinger et al., studied the mating behaviour of queens utilizing radio frequency identification (RFID) tags . Though the research produced no dramatically new outcomes, it was a neat utility of expertise and permits me to debate when mating flights happen and the affect of the climate in a little bit extra element.
The paper is Open Entry when you’d wish to learn it. I’m not going to undergo each refined wrinkle and nuanced argument within the research, however will as a substitute simply give attention to the vital ’take house message(s)’.
RFID tagged queens
That is one thing I don’t want to debate in something aside from cursory element as I wrote about it three weeks in the past in ’Chips with all the things’.
Or maybe I do? The publish was solely learn by about 25% of the guests who learn the next week’s ’What they don’t let you know’ … it’s virtually as if the hardcore science is much less attention-grabbing than anecdotes about beginning beekeeping. Certainly not?
Basically you stick a novel tag onto a bee and document when it enters or exits a hive utilizing a delicate reader on the hive entrance.
RFID tagged bees and RFID readers on a feeder
You don’t want to face by the hive and watch something.
All of the ‘observations’ are made automagically and recorded digitally for subsequent evaluation. You may subsequently monitor a whole lot of employees or dozens of queens concurrently, thereby growing the statistical robustness of the outcomes obtained.
The Heidinger et al., research monitored the mating flights of 64 queens.
Of those, 11 had been ‘lacking in motion’ and by no means returned to the mating nuc.
Fifty three (83% … a determine very near that quoted above from fully completely different research) mated efficiently and began laying eggs. Nevertheless, two of those managed to get out and mate efficiently with out ever being detected by the RFID reader, which means that flight occasions, frequencies and durations are from 51 queens .
The research was performed in two apiaries about 4 km aside in Center-Thuringia, Germany, in June/July.
Logistics and knowledge wrangling
Conducting all these subject research will not be simple. Queens need to be produced in batches after which launched to mating nucs.
Per week of dangerous climate means the queens could have aged earlier than they’ve an opportunity to fly.
What do you do about queens that return from a mating flight however that cluster beneath the mating nuc, solely getting into (and triggering the reader) after an hour or two?
To accommodate these vagaries the authors:
- grouped queens in keeping with age,
- thought-about flights lower than 3 minutes lengthy as orientation flights
- ignored mating flights of longer than one hour
And no matter filtered by from that pre-screening was then subjected to rigorous statistical evaluation.
Time and length of mating flights
Queens went on mating flights for 1 to five days, with a mean of two.2 +/- 0.98 day . In easier-to-comprehend phrases because of this about 70% of all of the queens went on mating flights on 1 to three days.
Because it’s usually quoted that queens depart the hive ‘as soon as to mate’ this is perhaps a shock to some.
Maybe much more shocking is that queens went on a complete of 1 to 16 mating flights, with a mean of 5.04 +/- 3.11.
One significantly enthusiastic queen went on 7 mating flights in at some point. The very definition of ’scorching to trot’.
The timing of queen mating flights
Over 80% of those mating flights passed off between 1pm and 4pm. From a sensible beekeeping standpoint, by avoiding this era for hive inspections you’ll considerably cut back the probabilities of being in the way in which when a queen returns to a mating nuc.
The length of mating flights
The typical size of a mating flight was a bit lower than 18 (17.69 +/- 13.19) minutes. Of roughly 255 mating flights (i.e. flights of 3-60 minutes length) monitored, about 180 (70%) had been of 20 minutes or much less.
All of those outcomes are in fairly good settlement with a wealth of literature collected utilizing completely different strategies over the previous couple of a long time.
Can we use a few of these figures to calculate queen mating flight distance?
Length x velocity = distance
I can discover nothing within the literature on the velocity at which a queen flies. Nevertheless, I do know that the escapee virgin queens I attempt to catch normally fly simply too quick 🙁
Let’s assume for the sake of argument that the queen flies at about the identical velocity as a employee bee. That is normally reported as 25 km/hr unladen and about 17 km/hr when laden with pollen or nectar.
Due to this fact, a queen mating flight of 20 minutes at 25 km/hr entails flying a complete distance of not more than 8.3 km. A ten minute mating flight at 17 km/hr equates to 2.8 km.
These distances embrace three parts, an inward and outward leg separated by the flight time throughout the DCA. Your guess is nearly as good as mine as to how lengthy the latter takes .
Nevertheless, not realizing one thing is the right alternative for some knowledgeable hypothesis (or, as right here , wild guesswork).
Wildly uninformed guesswork
The queen mates with a number of drones whereas within the DCA. Though every mating takes a really brief time (seconds) there may be competitors between the drones whereas they chase the queen, so she should keep throughout the DCA for an affordable interval.
Time for one more assumption … this time let’s assume that the queen spends one third of the length of her mating flight throughout the DCA or 4 minutes, whichever is the shorter .
If that had been the case, a ten minute mating flight at 17 km/hr, with a 3rd of the flight time being spent within the DCA, would imply the mating website was simply 940 metres from the hive. Conversely, if the queen spent not more than 4 minutes within the DCA throughout a 20 minute mating flight at 25 km/hr, then the mating website should be 3.33 km from the hive.
Both my guessestimate for the time spent within the DCA is just too excessive (fairly attainable), or the anticipated flight velocity of the queen is just too low (unlikely to be wildly flawed, she’s not going to hurry there at 75 km/hr) … or the typical distances queens journey to a DCA are considerably much less than these measured utilizing remoted queen and drone-producing colonies within the research cited earlier by Jensen, Peer or Klatt (see above).
Relationship of time spent in DCA and potential most mating flight distance
The desk above exhibits why I believe queens seemingly spend lower than 4 minutes within the DCA. Distances in pink are inside 2.4 km that Jensen confirmed 50% of matings happen in, these in yellow are throughout the 7.4 km that 90% of matings occured in .
The affect of the apiary
Let’s cease all this wild guesswork and return to the calming certainties of statistically compelling knowledge 😉
The Heidinger research concerned two apiaries separated by a couple of kilometres. All the information mentioned above makes use of recordings pooled from each apiaries. Nevertheless, queens in a single apiary went on extra mating flights than within the different. The distinction isn’t big (5 vs. 4 flights within the first three flight days), however is statistically vital.
Mating flight quantity (a) in numerous apiaries, and (b) at completely different temperatures
The queens are described as ‘sister queens’ and I assume this implies they’re all reared from larvae from the identical mom queen, although this isn’t made specific. If that’s the case, it suggests the geography of the realm influences queen mating flight frequency.
I say geography, fairly than drone availability, as additionally they added a further 47 (!) drone producing colonies close to one apiary and noticed no affect on queen mating flight traits.
Though the quantity of mating flights the queens went on differed, the length of the flights didn’t.
The information begin to get a bit extra sophisticated after they thought-about the age of the queens and the length of the primary, second, third and so on. flight … so I’ll skip all that and at last simply think about the affect of temperature on mating flights.
Some prefer it scorching
It’s recurrently acknowledged that virgin queens want calm, sunny afternoons with a temperature exceeding 20°C earlier than embarking on mating flights.
That is considerably disconcerting for a beekeeper dwelling on the cool/moist/windy – however exceeding lovely – extremities of the UK.
July rain squalls throughout Mull, Skye and the Sound of Sleat
The truth is, mating flights – by which I imply flights of 3-60 minutes (as no document of profitable mating on particular person flights was made) – occurred within the Heidinger research between a spread of 14°C and 25°C.
In cooler climate, queens tended to take extra mating flights (proven in the suitable hand panel on the graph above). The road is a ‘finest match’ and it’s clear there may be fairly a little bit of variation. Nevertheless, at 15°C the queens would take about 7 flights, in comparison with solely about 4 flights at 24°C .
Unsurprisingly subsequently, particular person mating flights had been of larger length throughout hotter climate. Once more the ‘finest match’ line is proven along with the variation within the major knowledge.
Relationship between temperature and particular person mating flight length
I discovered these final two graphs fairly reassuring … there have been plenty of flights under 20°C.
Geek alert
I’m beginning to get a bit obsessive about the climate right here on the west coast and put in a climate station final summer time. I solely have full information from July, however know we had a complete of solely 27 days on which the temperature exceeded 20°C from July and September.
August 2021 temperatures in Ardnamurchan
2021 was an impressive summer time right here on the west coast.
Subsequent 12 months I’ll have knowledge for the complete queen rearing season so hope to know this facet of the mating biology of my queens a little bit higher.
Conclusions
I’ve coated loads of floor on this publish … from the how far can she fly to mate? research of the 1930’s to what seem like brief length, and subsequently comparatively native, mating flights of RFID-tagged bees.
Understanding when a queen is more likely to go on a mating flight ought to assist you with timing your colony inspections. It ought to definitely assist curb your impatience as you wait on your queens to get mated.
Lastly, realizing that she will be able to fly on a lot cooler days than the widely-cited 20°C provides these of us dwelling in additional northerly latitudes some reassurance that our queen rearing efforts usually are not fully futile.
Notes
Some figures I meant to cite earlier; if the queen solely flies between 940 m and three.33 km to the DCA (see Length x velocity= distance above), and assuming colony densities of both 0.6/km2 or 3.2/km2 (see Apiary density about 3000 phrases in the past 🙁 ) the variety of hives ‘inside mating flight vary’ are between 1.7 and 111.
Fairly a spread, so ample alternative for good numbers of genetically various drones, although do not forget that apiaries usually are not evenly distributed and DCA’s are variable distances from drone producing colonies.
Deal with all of my numbers (and significantly my calculations) with appreciable warning.
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