wpadmin 
Synopsis: How do you precisely measure flight occasions and durations of a whole bunch of bees? And why would you need to do that anyway? Utilizing the identical know-how as Marks and Spencers label inventory gadgets, albeit on a smaller scale, it’s now attainable to observe 1000’s of honey bee flights very precisely.
Introduction
As a beekeeper, you’re nicely conscious of the dimensions and look of a honey bee. Contemplating the employees solely, they’re all just about the identical dimension and so they all look slightly comparable.
Yikes … I’m solely two sentences into the submit and I really feel the necessity to add a few attention-grabbing caveats:
- honey bees are uncommon (amongst bees) in that there’s a lot much less variation within the dimension of particular person employees throughout the inhabitants . This may support the accuracy of the waggle dance …
- nevertheless, that dimension is just not fixed. For causes that aren’t actually understood, the dimensions of honey bee employees will increase in the course of the season, by a small however important quantity .
OK, let’s get again on observe …
Contemplating this similarity, how are you going to inform if and when a explicit bee returns to the hive?
For instance, in case you’re within the distance from which a bee can efficiently return to the hive.
The plain factor to do is to mark the bee, in the identical manner you’ll mark a queen, with a small colored spot of paint on the thorax.
Small bees, large numbers, Posca pens
However, returning briefly to that very slight improve in dimension of honey bees in the course of the season, scientists usually must make a number of repeat observations to get statistically important outcomes . This turns into an issue as Posca solely do a restricted vary of colors … you may be capable to label bees with solely eight totally different colors.
Mr Blobby goes beekeeping
Or 64 mixtures in case you use two colors per bee … or 512 in case you use three colors collectively.
There are issues with this. Firstly, it takes a number of time to place two or three separate dabs of paint onto the thorax of a employee bee. Secondly, the thorax is a slightly small goal for a slightly fats pen (do you bear in mind your first try at queen marking? 😉 ).
A technique spherical that is so as to add dabs of paint to the stomach as nicely, or as a substitute, of the thorax. An even bigger goal definitely, however there are then points with making certain flexibility and never blocking the spiracles and a number of different issues, so not ultimate.
However, even in case you might label just a few hundred bees with distinctive colors, you’d then have to sit down subsequent to the hive entrance for hours at a time recording the arrival of blue-green-red (or was that green-red-blue? ).
Not ultimate … notably if you’re colourblind.
Truly, nearly inconceivable.
However, because of Leon Theremin, the Russian inventor of the eponymous musical instrument and developer of the spookily named listening machine “The Factor”, the RFID tag was created.
“The Factor”
“The Factor” was a covert listening machine hidden in a plaque proudly displayed contained in the American ambassador’s Moscow residence for seven years . It was a so-called ‘passive cavity resonator’. When energised by a radio sign of the right frequency (which – shock, shock – was transmitted by the Russians) it could decide up sound waves from the room, inflicting a membrane to vibrate. This vibration might be detected by a receiver (which – you guessed it – the Russians additionally had) and a decoder, thereby permitting conversations to be heard.
искусный as they are saying in Russian .
RFID tags and honey bees
And, on a considerably smaller scale, that’s just about how radio frequency identification (RFID) works.
There are two elements:
- an RFID tag or chip which is hooked up to no matter you need to uniquely determine. You’ll be completely acquainted with these are they’re usually hooked up to cost tags of things in retailers (the place they’re used for inventory management). They primarily include a microchip and an antenna.
- an RFID reader which emits the radio sign to activate the tag after which ‘reads’ the data despatched again. Usually this info features a distinctive serial quantity .
RFID tags may be tiny. Hitachi make one that’s 0.0025 mm2 which may retailer a 38 digit quantity. That’s smaller than a speck of mud. This brings an entire new set of issues because the antenna is so small that the vary is barely millimetres.
RFID tagged bees and RFID readers on a feeder
However an RFID chip that’s about 2 mm2 is sufficiently small to connect to the thorax of a bee and huge sufficient to be comparatively simple to detect … for instance, when passing a reader on the hive entrance.
Flying house
How far do bees fly?
I’ve mentioned this matter beforehand in a submit titled Sphere of affect. Traditionally these research have been performed by observing foraging exercise within the badlands of Wyoming (the place the bees needed to fly miles to seek out something), or by decoding the waggle dance to deduce distances.
However let’s ask a barely easier query.
What’s the furthest distance {that a} bee can efficiently return to the hive from?
Simply take into consideration the practicalities of the experiment.
You would predict that the additional away the bee begins, the much less possible it could be to efficiently return. As well as, the additional away the beginning level, the longer it could take to return.
You’d due to this fact want to observe numerous bees over a very long time.
As well as, you’d must make sure that the bees weren’t wind assisted, or – conversely – homing exercise was comparable no matter the route the bee was initially transported.
So, extra bees.
Time to chuck away these Posca pens and tag a number of hundred bees with RFID chips.
In 2011 Mario Pahl and colleagues did simply that and printed a research on the big scale homing of honey bees .
Like all good experiments, the research is elegant and comparatively easy. The paper is Open Entry if you wish to learn it your self … or hold studying for the juicy bits.
The important thing experimental particulars
Not too long ago returned pollen-laden foragers have been captured, tagged with an RFID chip ‘emitting’ a novel serial quantity, positioned in a black field, transported as much as 13 km from the hive and launched.
The hive entrance was fitted with an RFID receiver and the precise time the bee returned – if she returned 🙁 – was recorded.
Map of the experimental space. Triangles mark launch websites. Options mentioned in textual content.
At the least 20 bees have been launched in every of 33 totally different websites distributed to the north, south, east and west of the hive. The bees have been transported to the discharge websites in black containers so they may not get any positional info en route.
Anybody who transports bees (or cleared supers containing just a few straggles) any distance might be acquainted with their behaviour if/once you launch escapees from the automobile. They spiral upwards in widening circles till they disappear from sight.
That is similar to their behaviour on orientation flights. They’re – actually – getting their bearings.
The ‘native’ panorama
It’s value commenting right here concerning the panorama options across the hive.
The experiment was performed in Australia and the panorama across the hive was distinctive.
The hive was positioned 1 km east of Black Mountain (BM on the map above), 5 km north of Crimson Hill (RH ) and about 4 km west of Mount Ainslie (MA). There was a lake (Lake Burley Griffin, LBG) instantly south of the hive .
Panoramic view of the experimental space from the house hive.
There was good forage within the speedy neighborhood (inside 500 m) of the hive, together with the Canberra Nationwide Botanic Gardens. The authors due to this fact thought it “unlikely, however not inconceivable, that the bees knew the areas past the lake, behind BM and past MA”.
I counted all of them out, and I counted all of them again
Having launched the bees they then decoded the distinctive tag numbers because the bees arrived again on the hive over the following hours … and days.
The nearer the discharge website, the extra possible the bees have been recorded returning to the hive. Nevertheless, the homing charges – the proportion that returned for any given distance – have been primarily the identical for bees launched to the north, south and west.
In these instructions, no bees returned when launched from a lot over 6 km distance.
Homing charges. The proportion of bees that efficiently returned from distant launch factors.
In distinction, bees transported as much as 11 km east of the hive managed to return efficiently.
This was not because of the prevailing wind route which was from the north-east and about 15 km/hr, and would have due to this fact in all probability aided bees initially transported north as nicely.
Flight speeds
The homing velocity – assuming the bees flew in a straight line – was about 25 m/min for bees launched to the north, south and west, however considerably increased (35 m/min) for the bees launched to the east.
After all, the bees in all probability didn’t fly in a straight line .
These speeds, when transformed are only one.5 – 2.1 km/hr. Honey bees can fly at as much as 30 km/hr, however extra sometimes fly at round half that velocity.
At 15 km/hr all the launch websites have been inside an hour’s flight, indicating {that a} important period of time should have been spent trying to find the right bearing, slightly than truly flying alongside that bearing.
The one exception to those flight occasions/speeds was for bees launched on the other aspect of the lake. On this occasion, flight occasions elevated markedly regardless of the discharge websites being solely 400 m aside. It’s prompt that the bees minimised their flight over water by following the shoreline to the shortest crossing level in these situations.
Earlier than transferring on to the interpretation of the outcomes it’s value contemplating the numbers of bees studied, and the impossibility of doing such a analysis with out RFID know-how.
1073 bees have been tagged and launched. Of those, a complete of 394 returned (36%), although 75 of them (7% of launched, 20% of returning) took greater than 24 hours to seek out their manner again to the hive.
Even essentially the most devoted PhD pupil wouldn’t be able to doing this monitoring with out the assistance of know-how.
Why the longer and quicker flights from the east?
Contemplating it possible that the bees solely knew the world inside a few kilometres of the hive, how might they discover their manner again from as much as 11 km away, an epic journey that took a number of days?
And why did bees initially transported east return at each the next price and the next velocity?
It appears possible that for the brief to medium launch distances (say <4 km), the bees used the distinctive form of BH to information them again to the hive. Since this mountain was instantly adjoining to the house apiary the bees could be acquainted with it.
Alternatively, since bees are recognized to typically exploit explicit flight traces primarily based upon underlying panorama options, the worldwide landmarks similar to BM and MA might information the bees to the subsequent path phase of the flight line.
That wasn’t the query although … the query was why was it solely bees flying from the east that efficiently returned from distances as much as 11 km away?
Getting their bearings
Bees launched east of MA couldn’t ‘see’ the hive-adjacent BM (as MA is in the way in which). Nevertheless, the authors counsel that – by flying west in direction of a excessive level on the skyline (which initially occurred to be the mountain MA) – the bees might then “proceed on to BM”, the place the acquainted native options then lead them house.
While that makes some sense to me, it additionally makes an assumption that the bees one way or the other fly up and over MA to get a view of BM. With out that view, what else entices them to fly additional west?
Do numerous the bees ‘misplaced’ coming back from the east truly find yourself expiring throughout their futile seek for a hive instantly to the east of MA? The truth that these profitable lengthy journeys took ‘a number of days’ (the exact occasions usually are not indicated for particular person bees) signifies that the bees clearly spent a very long time looking out.
There’s a further conclusion that may be reached from these long-distance journeys. Not solely would time have been spent flying and looking out, however the bees would even have needed to make refuelling stops. A full crop of syrup is barely ample to maintain a bee flying for 25 minutes, or about 7 km at a typical flight velocity of 15 km/hr . Subsequently, the bees would have needed to acquire nectar a number of occasions on their journey.
So, what’s new?
In all honesty, not loads.
The aim of describing this research wasn’t as a result of it unearthed some beforehand unknown particulars of the foraging or flight vary of honey bees. Somewhat it was to introduce the ideas of uniquely tagged particular person queen bees and utilizing automated ‘readers’ to detect their actions.
It’s comparable, however totally different, from the research that contain uniquely barcoding bees I’ve described earlier than.
Flight homing distances are thought of a very good indicator of the utmost potential foraging ranges. The figures decided utilizing RFID-chipped honey bees are in broad settlement with the figures reported in earlier analogue research.
These place honey bees roughly mid-table within the league of ‘bee foraging distances’ … Ceratina smaragdula (a inexperienced metallic bee) goes no additional than 200 m, whereas the South and Central American orchid bee Euplusia surinamensis boldly travels as much as 23 km.
A number of the similar authors utilized this method to research whether or not neonicotinoids have been detrimental to the foraging behaviour of honey bees . At excessive, however sub-lethal concentrations, foraging exercise was lowered and foraging flight occasions elevated. Nevertheless, at field-relevant nectar and pollen concentrations no hostile results have been noticed. This research used RFID readers at each the hive and the feeder to document further options of the foraging flight that might not have been attainable manually.
You’ll realise, from the primary full paragraph of this part, that I’d meant to debate research on queen bee (orientation and mating) flights. As tends to occur, I bought somewhat distracted by espionage, the primary digital musical instrument, the names of mountains and Posca pens, so the queens must wait till one other time.
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