In the longer term these sheds could together accommodate at least a dozen full colonies. However, in the shorter term it has allowed me to rationalise the storage, giving much more space to work with the colonies in the larger shed.
Supers and brood in the storage shed have all been tidied (see below) and are in labelled stacks ready to use. The other side of the store contains stacks of floors, split boards, clearers and roofs.
It’ll get messier as the season progresses, but it’s a good start.
I also spent a couple of weekends making some minor improvements to the bee shed following the experience last season.
The lighting has been increased and repositioned so it is ‘over the shoulder’ when doing inspections. On a dull winter day it is dazzlingly bright 1 but I fear it will still not be enough. I’m looking at creating some reflectors to direct the light better.
I’ve also used a few tubes of exterior sealant to block up all the holes and cracks around the edge of the shed roof. Last season was a bad one for wasps and we were plagued with the little stripy blighters.
Tidy the frames
Two of the most valuable resources a beekeeper has are drawn super frames and capped stores in brood frames.
Look after them!
I often end up uniting colonies late in the season, but then overwinter the bees in a single brood box. This means I can end up with spare frames of sealed stores. These should be protected from wax moth and mice (or anything else) as they are really useful the following year for boosting colonies that are light on stores or making up nucs.
Drawn supers can be used time and time again, year after year. They also need to be protected but – if your extraction is as chaotic as mine – they also usually need to be tidied up so they are ready for the following season.
I load my extractor to balance it properly, rather than just super by super. Inevitably this means the extracted frames are all mixed up. Since frames are also often drawn out unevenly this leaves me with a 250 piece jigsaw with billions of possible permutations, but only a few correct solutions.
Little and large – untidy frames and a breadknife
And that’s ignoring all the frames with brace comb that accumulate during a good flow.
So, in midwinter I tidy up all the cleared super frames, levelling off the worst of the waviness with a sharp breadknife, removing the brace comb, scraping down the top bar and arranging them – 9 to 11 at a time 2 – in supers stored neatly in covered stacks.
And, if you’ve got a lot, label them so you know what’s where.
An hour or two of work on a dingy midwinter day can help avoid those irritating moments when – in the middle of a strong flow – you grab a super to find it contains just five ill-fitting frames, one of which has a broken lug.
Before – brace comb
After – all tidy
White wax for candles
The wax removed during this tidying up is usually lovely and white. Save it for making soaps, cosmetics or top-quality candles.
Brood comb has a finite life. After about three years of repeated brood rearing cycles it should be replaced. Old comb contains relatively little wax but what’s there can be recovered using a solar or steam wax extractor. This also allows the cleaned frames to be re-used.
Processing a few dozen brood frames with a solar wax extractor during a Scottish winter is an exercise in futility. For years I’ve used a DIY steam wax extractor which worked pretty well but was starting to fall apart. I therefore recently took advantage of the winter sales and purchased a Thorne’s Easi-steam3.
Melted out frames
Processed wax blocks
The Easi-steam works well and with a little further processing generates a few kilograms of wax for making firelighters or trading in … and a large stack of frames for re-use.
Remember to keep a few old darkbrood frames aside for using in bait hives.
Keep an eye on your bees
In between all these winter chores don’t forget to check on your bees.
There’s not a lot to do, but these checks are important.
Make sure the entrances are clear, that the mouse guards 4 are in place and that the roofs are secure.
Storm Eric brought us 50-60 mph winds and a couple of my hives lost their roofs. These had survived a couple of previous storms, but the wind was from a different direction and lifted the roofs and the bricks stacked on top. I got to them the following day but we’ll have to wait until the season warms up to determine if there’s any harm done.
Fondant top up
Finally, as the days lengthen and it gets marginally warmer colonies should have started rearing brood again. Make sure they have sufficient stores by regularly ‘hefting‘ the hive. If stores are low, top them up with a block or two of fondant. This should be placed directly over the cluster, either over a hole in the crownboard or on the top bars of the frames.
The life cycle of the ectoparasitic mite Varroa destructor essentially consists of two stages. The first is within the capped cell, where reproduction takes place. The second occurs outside the capped cell when the recently-mated female progeny mites matures while riding around the colony attached to a nurse bee.
Almost without exception this second stage is termed the phoretic phase.
Phoretic is an adjective of the word phoresy. Phoresy is derived from the French phorésie which, in turn, has its etymological origins in the Ancient Greek word φορησις.
And φορησις means being carried.
Which partly explains why the correct definition of the word phoresy is:
An association between two organisms in which one is carried on the body of the other, without being a parasite [OED]
Phoresy has been in use for about a century, with the word phoretic first being recorded in the Annals of the Entomological Society of America (25:79) in 1932:
It is possible, as suggested by Banks (1915), that such young mites are phoretic, being carried about from place to place on the host’s surfaces.
And, no, they weren’t discussing Varroa.
“Without being a parasite”
These are the critical words in the dictionary definition of phoresy which makes the use of the word phoretic incorrect when referring to mites on nurse bees.
Because mites on nurse bees are feeding – or at least a significant proportion 1 of them are.
They are therefore being parasitic and so shouldn’t be described as phoretic.
Last week I discussed the recent Samual Ramsey paper presenting studies supporting the feasting of Varroa on the fat body of bees.
In the study they harvested bees from a heavily mite-infested hive and recorded the location on the bee to which the mite was attached.
The majority were attached to the left underside of the abdomen. More specifically, the mite was wedged underneath the third abdominal tergite 3.
What were they doing there? Hiding?
Yes … but let’s have a closer look.
Ramsey and colleagues removed some of the mites and used a scanning electron microscope to examine the attachment point on the bee. Underneath the tergite there is a soft membrane. The imprint of the body of the mite was clearly visible on the membrane.
Scanning EM of Varroa feeding location on adult bee
The footpads of the mite were left attached to the membrane (left image, white arrows), straddling an obvious wound where the mouthparts had pierced the membrane (black arrow). Between them, the inverted W shape is presumably the imprint of the lower carapace of the mite.
The close-up image on the right even shows grooves at the wound site consistent with the mouthparts of the mite.
These mites were feeding.
Varroa belongs to the order (a level of classification) Mesostigmata. Most mesostigmatids feed using a process termed extraoral digestion.
Extraoral digestion has also been termed ‘solid-to-liquid’ feeding. It involves the injection of potent hydrolytic enzymes which digest solid tissue, converting it to a semi-solid that can be easily ingested. It can reduce the time needed to feed and it increases the nutrient density of the consumed food.
If Varroa fed on haemolymph it wouldn’t need to use extraoral digestion. Instead it would need all sorts of adaptations to a high volume, low nutrient diet. Varroa doesn’t have these. It has a simple tube-like gut parts of which lack enzymatic activity … implying that digestion occurs elsewhere.
A picture is worth a thousand words
Do the images of feeding mites support the use of extraoral digestion?
EM cross-section of Varroa feeding
The image above 4 shows the cross-section of a Varroa (V), wedged under the tergite (Te), feeding through a hole (arrow in the enlargement on the right) in the membrane (M). The fat body (FB) is immediately underneath the membrane. The scale bar is incorrectly labelled 5.
A close-up of the wound site shows further evidence for extraoral digestion.
Feeding wound at higher magnification
Beneath the wound site (C, arrow) are remnants of fat body cells (white arrow) and bacteria (black arrow; of two types, shown in D). A closer look still at the remnants of the fat body (E and F) shows cell nuclear debris (blue arrows) and lipid droplets (red arrows).
These images are entirely consistent with extraoral digestion of fat body tissue by feeding Varroa. The presence of bacteria near the wound suggests that bacterial infection may result from Varroa feeding, possibly further contributing to disease in bees.
So, pedantically it’s not phoresy
So-called phoretic mites, unless they’re on the thorax or head of the bee, are not really phoretic. They are being carried about, but they are also likely feeding. By definition that excludes them from being phoretic.
Instead they are ectoparasites of adult bees.
What are the chances that beekeepers will stop using the term phoretic?
And, of course, it doesn’t really matter what the correct term for them is.
What’s more important is that beekeepers remember that it’s at this stage that mites are susceptible to all miticides.
The June gap
But it’s also worth thinking about the potential impact of brood breaks.
During brood breaks all the mites in the colony must be ‘phoretic’.
Generally, the majority of the mites in a hive are in capped cells. Depending upon the stage of the season, the egg-laying rate of the queen and other factors, up to 90% of the mites are associated with developing pupae.
But as the laying rate dwindles more and more mites are released from cells and become ‘phoretic’, unable to find a suitable late-stage larva to infest.
And which bees do the mites associate with?
Nurse bees primarily, for reasons I’ll discuss in the future. But – spoiler alert – one of the reasons is likely to be that they have a larger fat body.
So, a mid-season brood break (e.g. the ‘June gap’) is likely to result in lots more nurse bees becoming both the carriers and the dinner of the mite population.
Some or many of the nurse bee cohort may perish, perhaps from damage to the fat body or from the viruses acquired from the mite. However, bees exhibit phenotypic plasticity, meaning that older bees can revert to being nurse bees when the queen starts laying again.
Late season brood breaks
In late summer mite levels are usually at their highest in the hive. A brood break occurring now will release a very large number of mites to parasitise the adult bee population.
Presumably these mites select the bees best able to support them 7.
And which bees are these? The nurse bees of course. But it’s also worth remembering that there are key physiological similarities between nurse bees and winter bees. Both have low levels of juvenile hormone and high levels of vitellogenin (stored in the fat body).
So I’d bet that the ‘phoretic’ mites during a late season brood break would also preferentially associate with any early-produced winter bees.
Furthermore, once the queen starts laying again – perhaps in early/mid-autumn – the winter bees being produced would be subjected to the double-whammy of high levels of mite infestation and potential damage from ‘phoretic’ mites.
More work is required to model or actually measure the impact of late season brood breaks, high levels of ‘phoretic’ mites, nurse bee numbers and winter bee development.
Compare two colonies of a similar size with a similar mite load, treated at the same time in early autumn with an appropriate miticide. If one of them experienced a late summer brood break (pre-treatment) and consequent high levels of ‘phoretic’ mites, does this reduce the chances of the colony surviving overwinter?
Who knows? Lots and lots of variables …
Fundamentally, it remains important to treat colonies early enough to protect the winter bee population. You’ve heard this from me before and you’ll hear it again.
However, it’s something to think about and I can see ways in which it might influence the strategy and timing of mite control used. I’ll return to this sometime in the future.
A little over a year ago reports started to circulate of a study showing that Varroa feed on the fat body of bees rather than on haemolymph.
Having worked in Glasgow through the early noughties the title of this post was a no-brainer and an outline draft was written in December 2017. However, the peer-reviewed paper wasn’t published until last month, so it’s only now we’ve got the chance to judge the study and consider its implications.
Varroa feed on hameolymph, right?
Historically this was the accepted dogma. However, the experimental data supporting this conclusion – based upon labelling bees with radioactive isotopes and seeing what the mites acquired after feeding – was really not definitive. The experiments had been done in the 1970’s and the specificity of the labelling was a bit dubious. In addition, during the intervening period scientists had determined that, unlike vertebrate blood which is rich in cells and nutrients 1, haemolymph has little of either and is actually a pretty lousy food source.
In addition, and somewhat more circumstantially, Varroa control using chemotherapeutics fed to bees (and subsequently taken up by the mite during feeding) had been relatively disappointing.
Perhaps these chemicals weren’t getting to the right tissues of the bee?
Perhaps Varroa don’t feed on haemolymph after all?
The Ramsey study
This new study reports three independent experiments that, together, indicate that Varroa actually feed on the fat body of bees, rather than on haemolymph. The paper is so-called ‘open access’, so anyone can access it and therefore I’ll just provide a synopsis of the important bits.
The questions Samual Ramsey and colleagues attempted to answer were:
Where on the bee do mites feed? Is it primarily or exclusively near the fat body?
When Varroa feeds, what host tissues are ingested?
What sort of diet is required to maintain Varroa and allow their reproduction in vitro2.
Location, location, location
The authors counted phoretic mites on 104 bees. Over 95% of them were located on the underside of the body, predominantly on the left side of the bee, under the tergite or sternite3 on the third metasomal segment (i.e. the second visible segment of the abdomen).
Mite location on nurse bees
This position is consistent with feeding on the fat body tissues which are most abundant under the inner ventral surface of the metasoma.
Bees were fed with Nile red, a lipophilic fluorescent stain that preferentially accumulates in the fat body. They co-fed bees with uranine, a differently coloured fluorophore that accumulates in the haemolymph. They then allowed mites to feed on the fluorescently labelled bees and subsequently photographed the mites under fluorescent light.
The rationale here was straightforward. If the mites fed on the fat body they would stain red due to taking up the Nile red stain.
Mites visualised after feeding on fluorescently labelled bees
Which they did.
It was notable that the red stain predominantly accumulated in the rectum and gut of the mite (image O above). The authors conducted all sorts of controls to confirm that the stains actually stained what they were supposed to – you can view these in the paper.
In the final part of the study the authors maintained mites in vitro (in an incubator), feeding them on a diet containing increasing amounts of fat body or haemolymph. These are tricky experiments and in some way the least satisfactory part of the study.
Two results suggest that fat body was beneficial or essential to the mites. Firstly, only mites that had 50% or more fat body in the diet survived for 7 days. Secondly, there was a dose response to the amount of fat body in the diet and fecundity. Mites on a 100% fat body diet exhibited 40% fecundity, the highest level observed in the study.
What can we conclude from the Ramsey study
Of the three experiments presented, the Nile red fat body stain uptake by mites is reasonably compelling.
The feeding position study is essentially correlative, but there could be other interpretations of the data. For example, that location on the bee might be the least accessible to a ‘grooming’ bee. Perhaps it’s a survival mechanism?
Survival and fecundity in in vitro studies wasn’t great. However, in defence of the authors, fecundity of mites under natural conditions can be as low as 40% and is not higher than 80%. Not all mites have baby mites. Thankfully.
Only 20% of the mites survived one week under in vitro conditions, even on a 100% fat body diet. In contrast, mites fed haemolymph alone died within 48 hours. This poor level of survival was surprising and suggests other essential components of the diet were probably missing.
Other published studies have shown reasonable survival of Varroa for at least 3 days, with at least one report of mites surviving on flowers for up to 7 days. I’m also aware that other laboratories can maintain mites in vitro for longer than 7 days without using any honey bee-derived components in the diet.
Hang on … what is the fat body anyway?
The fat body is multi-functional. It has been compared to the vertebrate liver and adipose tissue. It acts as a major organ for nutrient storage, energy metabolism and detoxification of things like pesticides.
Vitellogenin made by and stored in the fat body reduces oxidative stress and is associated with extending the longevity of overwintering bees. The fat body also has critical roles in metamorphosis.
So, not only multi-functional, but also very important.
Significance of the results … is this a game changer?
This paper has been discussed online as a ‘game changer’. That’s probably a bit strong. Whilst the fluorescent stain uptake study is reasonably convincing it must be remembered that it was conducted on adult bees.
Do mites on pupae also feast on the fat body?
This will have to be determined in the future. It’s a more difficult experiment of course.
The other two studies, and a number of additional small observations I’ve not discussed here, are certainly supportive, but not alone hugely convincing. The in vitro study in particular will be interesting to compare with (currently unpublished) studies from other laboratories that do not use honey bee fat bodies in their mite feeding and maintenance diet.
Does it matter what part of the bee the mite feeds on?
Clearly it does for the mite, but what about the beekeeper?
I think this study is significant for the beekeeper for two reasons – the first will only be relevant if and when lipophilic miticides are developed, the second matters right now.
Strategies are being developed to add highly specific miticides to the diet of bees which are then delivered to Varroa when the mite feeds. To date, these have been rather underwhelming in their performance. If Ramsey is right, modification of these miticides to make them lipophilic (like the Nile red fluorphore) will concentrate them in precisely the right place to ensure the mites get a lethal dose.
A key product of the fat body is vitellogenin. The long-lived overwintering bees have high levels of vitellogenin. Mites feeding on, and depleting, the fat body would be expected to result in reduced vitellogenin levels in the bee 4. This would explain why high Varroa levels are associated with reduced longevity of winter bees and consequently increased overwintering colony losses.
The most important take home message
To prevent mites that feed on fat bodies from damaging vitellogenin production miticides have to be used early enough to protect the winter bees.
In the paper Ramsey makes the statement:
Simple reduction of mite loads late in the season to decrease the overwinter parasite load may not be enough, as it still allows for the mites to damage tissue critical to the process of overwintering …
A treatment schedule that includes treatment in late summer or early fall before mites can significantly damage fat body in developing winter bees would likely be more effective.
What the Ramsey paper adds is the piece of the jigsaw possibly explaining why late summer treatment is so important.
Chewin’ the Fat was a four-series Scottish comedy sketch show. It was broadcast from 1999 to 2002, with further Hogmanay specials until 2005. The show had a recurring cast of characters and sketches including The Big Man, The Banter Boys, The Lighthouse Keepers, Ballistic Bob and Taysiders in Space.
Gonna no’ dae that – The Lighthouse Keepers
Chewin’ the Fat was filmed in and around Glasgow (where I worked at the time) and the characters parodied a range of local ‘types’ … pretentious Kelvinsiders, Glaswegian gangsters, narcissistic golfers, The man from Kilmacolm, and shellsuit-wearing, chain-smoking, hard-drinking Glaswegian neds.
It was a bit rude and definitely an acquired taste. Without subtitles, some of the scenes would probably have been unintelligible south of the border.
for convenience it should have a Varroa tray to monitor mites that fall through the OMF
if used when vaporising oxalic acid-containing treatments it needs to be reasonably ‘gas tight’
How does the Abelo poly National floor 4 meet these requirements?
First, the good points
The Abelo floors are sturdy, ready-painted and nicely cast (molded? moulded? formed?) from dense poly. The paint (all mine are green or yellow though they may do blue as well) is tightly bonded to the poly surface and doesn’t easily wear away. I think the white patches in the picture below were there from manufacture, not from use.
Abelo floor – drone’e eye view
The floors have an reasonable area of mesh, securely held in place. The mesh area isn’t as great as some wooden floors, but is at least as good as my homemade kewl floors.
On either side of the floor, on the underside, there is a recessed handhold that really helps in lifting hives. These recesses are also convenient anchoring points for an elasticated bungy to hold the roof in place 5.
Worms-eye view of an Abelo floor
Probably the best feature of these floors is that they’re fully compatible with other National hive components. I’ve mixed them with cedar or Swienty poly brood boxes and they fit perfectly. The interface between the boxes is flat, the correct dimensions and pretty hard-wearing.
Abelo do tend to design rather ‘fiddly’ equipment and they’re verykeen on ventilation.
They usually include these fiddly design features to allow increased ventilation – or at least the option for it.
The entrance block is in two parts (see photo above). A grey plastic reversible full-width block that drops into two vertical slots on either side of the landing board. One way up the entrance is reduced to ~8cm wide. Inverted and the entrance is sealed.
Well, sort of sealed 🙁
There are four vertical ventilation holes that remain open on either side of the entrance block. Are these really needed? After all, the ventilation provided by the OMF far exceeds the little bit extra through the entrance block.
There’s a second green 6 plastic slider that can be added to the entrance block to provide an integral mouse guard. Or – more options – if inverted it can be used to further reduce the entrance to one bee width (or closed off altogether).
Ventilation and Varroa trays
Returning to the underside of the floor, the weakest part of the design is the Varroa tray.
Abelo floor Varroa tray – inserted
The tray is unpainted polystyrene, square with a shallow lip. It slots into a recess in the underside of the floor, supported by two metal runners.
The area of the tray is approximately 75% of the floor area of a National brood box. With a full colony, some of the Varroa will fall outwith this area. This isn’t a major issue, but it could lead to underestimating the mite load in the colony.
The tray slides in and out easily, facilitated by a small protruding handle on the underside.
Abelo Varroa tray half withdrawn
Unfortunately, there are some large gaps around the tray when it’s in place. If you sublimate oxalic acid a significant proportion of the vapour escapes around the edges of the Varroa tray.
The gaps around the tray are awkwardly shaped, so it’s not straightforward to plug them … other than with foam blocks perhaps. It’s also not possible to easily temporarily replace the tray with a Correx sheet. If you did it would need holding in place so potentially putting you too close to the hive and clouds of escaping oxalic acid vapour.
Resourceful beekeepers will work out solutions to these problems, but it would have been better if the defects weren’t designed into the floor in the first place.
Abelo floor, Varroa tray inverted
And, before you ask, inverting the tray does not significantly seal off the gaps!
Poly Varroa trays
It is possible to make reasonably ‘vapour-tight’ poly Varroa trays. For example, the Thorne’s Everynuc has one that slots neatly in place. I’ve used these dozens of times and there is very little loss of vapour in my experience.
However, the Abelo floor (and the Everynuc Varroa tray) has the additional problem of being unpainted polystyrene. These very quickly become stained, with pollen, bee faeces and all of the usual rubbish that falls through the floor.
Abelo poly Varroa tray
This staining makes counting Varroa much more difficult.
Again, a couple of coats of white gloss paint would seal the surface of the tray. However, this rather undermines the attraction of the ready-painted Abelo hives 🙁
Alternatively, you could source some white Correx sheet to make an insert that would be easy to draw a grid on, count Varroa in and clean.
And, inevitably, easy to lose.
Floors done well
In summary, the problems with these Abelo floors are three-fold.
Intentionally (the entrance block) and unintentionally (the Varroa tray) leave too much ventilation to conveniently be used when sublimating oxalic acid. The success of these depends upon retaining the vapour within the hive while it condenses on internal surfaces. Allowing it to leak out excessively simply makes the treatment less effective.
Even if you don’t control Varroa by oxalic acid vaporisation the Varroa tray gets dirty quickly and is difficult to clean.
Finally, it’s not possible to securely fix the entrance for transporting colonies, other than by using loads of gaffer tape. Even if you do, the large landing board on these floors makes strapping hives together awkward.
Most of my hives have homemade kewl floors. These probably cost about £6 each to make and have none of the problems listed above. They offer additional benefits as the L-shaped entrance ‘tunnel’ prevents mice from entering the hive and reduces robbing by wasps.
Kewl floor and Correx landing board …
These DIY floors have a simple, easy to clean, Correx Varroa tray that is much more ‘gas-tight’ than the Abelo design. An L-shaped wooden entrance block can be screwed in place for transport and the landing board is effectively integral to the floor, replaceable if damaged and does not project in a way that inhibits strapping hives together for transport.
Cedar floor and plywood tray …
Kewl floors are unsuited to being used in the bee shed. For these hives we use slightly modified cedar floors made by Peter Little of Exmoor Bees and Beehives. These have a ply removable Varroa monitoring tray that provides an excellent ‘gas-tight’ fit when sublimating. These floors are not inexpensive, but they are very well made.
Cedar floor with closed monitoring tray
Considering the quality of the rest of the Abelo National hives, these floors are a disappointment. I use them if I’ve run out of everything else and I kick myself when I discover – as I did a few weeks ago – that there are still some in use when the midwinter mite treatment is needed.
What do you call a stack of Abelo poly floors …
Floor and flaw are homonyms, two words that sound the same but have different meanings. Floor, meaning in this context the ‘base of any cavity’ probably dates back to Old English (Anglo Saxon) ~317AD. Flaw in comparison is a young upstart, with the first recorded use being by Robert Hooke in 1665. Hooke was, amongst other things a microbiologist, and he used the word flaw in his book, Micrographia, which is about his observations using a microscope (and telescopes). Hooke was the first to use the word ‘cell’ following microscopic examination of plant cells, which have walls, because the appearance reminded him of honeycomb.
Every year, usually around Christmas, I make a batch of mead.
About a year later I bottle the mead and leave it to mature.
A year or more later I start drinking the mead … if it’s drinkable 😉
If at first you don’t succeed …
The last couple of batches have been, if not spectacular, certainly very drinkable.
I expect them to improve further with age 1 and so have tucked them away for special occasions over the next 12-18 months … or longer 2.
Clearly this isn’t a quick process.
The early batches I made were pretty rough. Some were ditched at – or rather just before – bottling. However, I’ve now settled on a recipe (which means found … I claim no originality for it) that has worked well for at least three batches in a row.
Here it is.
You’ll need a small amount of equipment, all of which is readily available from a brewing and winemaking store. I’ve used Hop and Grape, but there is lots of choice online. In England, Wilkinsons is also a good source of inexpensive brewing supplies.
Siphon (or simple piece of tubing)
Good sized saucepan
Ready for fermentation …
~4lb of well-flavoured honey
1 mug of cold tea
1 teaspoon of citric acid
1 teaspoon of yeast nutrients
5g of good quality white wine yeast. I’ve had the most success with Lalvin D47.
5 litres of still bottled water
Fermenting mead …
Prepare a mug of tea. Use boiling water and one tea bag, leave it to go cold and discard the tea bag. While it’s cooling prepare the yeast starter and sterilise everything.
Add the yeast to a clean glass containing 100ml or so (quantity isn’t critical) of warm water at ~40°C. Stir to disperse the yeast and leave at room temperature to rehydrate.
Add the honey to the saucepan and add about 2 pints of water. Warm over a gentle heat, stirring regularly to completely dissolve the honey. It doesn’t need to get hotter than ‘hand hot’. Once the honey is completely dissolved take the saucepan off the heat and allow to cool. While that’s happening prepare the demijohn.
Thoroughly sterilise a demijohn. I use crushed Campden tablets as I’m ‘old skool’, there are probably newer and better ways to do this now. At the same time sterilise a rubber bung for the demijohn, a funnel and an airlock. Rinse the cleaned demijohn very well (tap water) and then add ~1 pint of bottled water.
To this demijohn, using the funnel, add the honey mix, the cold tea, citric acid and the yeast nutrients. The temperature should now be around 30°C.
Add the yeast starter. There will still be a considerable volume of the demijohn still empty (see the image above).
Add the bung and, holding the bung tightly in place, shake the demijohn very vigorously.
More, shake it some more. I don’t know if it really helps, but it feels like you’re doing something important and constructive 😉
Replace the bung with an airlock part-filled with bottled water.
Place the demijohn somewhere out of the way to ferment. The temperature (at least for Lalvin D47) needs to be 15-20°C but not any higher or it can produce ‘off’ flavours. I wrap the demijohn in bubble wrap or old blankets to help keep the temperature stable 3. It needs to be out of the way as you don’t want to move it and disturb things during fermentation.
Bubbles will start in 6-18 hours. Initial fermentation can be very vigorous which is why lots of headspace was left at the beginning.
After 48-72 hours fermentation will have steadied to about one bubble every few seconds. The sound is hypnotic 🙂 Once fermentation has steadied remove the airlock, top up with water to within 1″ of the neck of the demijohn and replace the airlock.
Let fermentation continue. After 2-3 months fermentation will have almost or completely stopped. The demijohn will have a thick layer of yeast settled at the bottom of the bottle.
Avoiding the yeast layer, siphon the mead into a new, sterilised demijohn. Don’t disturb the yeast layer … don’t worry about not getting every last drop out of the demijohn.
Top up the new demijohn with ~1:3 w/w honey in warm water (i.e. 227g of honey dissolved in 750ml of water). Replace the airlock. Fermentation will start again.
Once fermentation has completely finished – this takes a variable length of time – the mead should be crystal clear 4.
Bottle the mead. Test it (of course!) and leave it somewhere dark and cool to mature for several months.
Additional notes and comments
This is a very basic guide to making mead. That’s because, despite making it for a few years, I’m still very much a beginner. There are hundreds of guides and at least as many recipes online. Read a few, but then just have a go … don’t get bogged down in the minutiae. If you can’t find Lalvin D47 use generic white wine yeast.
Use well-flavoured honey. Don’t use something bland or insipid. Many people use heather honey for mead though the best batches I’ve made have always been with a good midsummer mixed floral honey.
Using the recipe above the last few batches have cleared perfectly. One or two early attempts remained cloudy after racking it off and I remedied this by adding a bit of bentonite.
I’m a bit of a heathen and usually use 500ml “Grolsch-type” bottles, which are more properly termed swing-top bottles. If you’re intending to compete in your association annual honey show make sure you use the correct type of bottle … which will not be a swing top 😉
Whatever bottle style you use make sure it is made of clear glass … you want the lovely golden amber colour of the mead to shine through.
I’ve no idea of the alcohol content as I’ve lost my hygrometer. Lalvin D47 can tolerate 14-16% alcohol which gives you an idea of the upper limit it will reach.
I know the stuff I’ve made is reasonably potent. Test your mead in moderation. If you like the flavour I’d recommend NOT guzzling the entire bottle in one sitting … particularly if you use standard volume (75cl) wine bottles 5.
Remember that you can’t sell alcohol without a licence.
Drink it with friends and sell them lots of honey when their defences are lowered 😉
Actually, there’s no evidence that bees display or perceive most of the emotions often attributed to them 1.
Happy? Who knows? But certainly not healthy …
A more accurate statement might be “Healthy bees are more productive, they are less likely to die overwinter, less likely to be robbed out by wasps or neighbouring strong colonies and their parasites and pathogens cannot threaten the health of other honey bee colonies or, through so-called-pathogen overspill, the health of other pollinators.”
Yes … but it doesn’t exactly trip off the tongue 😉
Whether it makes the bees happy or not, beekeepers have a responsibility to look after the health of their livestock. This includes controlling Varroa numbers to reduce the levels of pathogenic viruses in the hive.
How well are virus levels controlled if mite levels are reduced?
I’ll get to that in due course …
Midwinter mite massacre
The 2018 autumn was relatively mild through until mid/late November. In the absence of very early frosts colonies continued rearing brood.
We opened colonies in mid-November (for work) and found sealed brood, though it was clear that the laying rate of the queen was much-reduced.
These are ideal conditions for residual mite replication. Any mites that escaped the late summer/early autumn treatment (the ideal time to treat to protect the overwintering bees) continue to replicate, resulting in the colony starting the following season with a disappointingly high level of mites.
I’ve noted before that midwinter mite levels are paradoxically higher if you treat early enough in the autumn to protect the all-important winter bees.
Consequently, to start the year with minimal mite levels, I treat in midwinter with a trickled or vaporised oxalic acid-containing (OA) treatment.
A combination of colder weather (hard frosts in late November) and brood temperature measurements 2 indicated mid-December was a good time to treat.
Midwinter mite massacre
In one of my apiaries ten colonies were treated. Some were definitely broodless (based upon Arnia hive monitoring). Others may have had brood, but colonies were not routinely checked.
Over the four day period after vaporising these ten colonies dropped a total of 92 mites. More than 50% of these were from just one double-brooded colony. Overwintering nucs 3 dropped no mites at all in the 12 days following treatment.
This was very encouraging. These are lower midwinter mite levels than I’ve seen since returning to Scotland in 2015.
The one colony with ‘high’ mite levels received two further treatments (on the 22nd and 27th) in an attempt to minimise the mite levels for the start of the season. Going by the strength of the colony and the debris on the Varroa tray it was presumed that this colony was still rearing brood.
Mite drop following the third treatment was negligible 4.
Why are mite levels so low?
I think it’s a combination of:
Use of natural, organic, bee-centric and biodynamic beekeeping methods
Very tight control of mite numbers in the 2017/18 season, primarily by correctly timing the winter and the late-season autumn treatments. This is simply good colony management. Anyone can achieve this.
A brood break midseason and/or a broodless period when splitting colonies (both give opportunities for more phoretic mites to be lost through grooming). Undoubtedly beneficial but season-dependent. I’ll be discussing ways to exploit these events in posts next year.
A low density of beekeepers in Fife, so relatively little drifting or robbing of poorly managed colonies from neighbouring apiaries. Geography-dependent. Much easier in Fife than Warwickshire … and easier still in Lochaber.
And what do less mites mean?
Varroa is a threat to bee health because it transmits pathogenic viruses when feeding on developing pupae.
Generally, the higher the level of infestation with mites, the higher the viral load 5. This has been repeatedly demonstrated by studies from researchers working in the UK, Europe and the USA.
It is well-established that colonies with high viral loads have an increased chance of dying overwinter, due to the decreased longevity of bees infected with high levels of virus.
In our work apiaries we regularly measure DWV levels. For routine screening our limit of detection is around 1,000 viruses per bee.
We don’t actually count the viruses. They’re too small to see without an electron microscope 6.
Instead, we quantify the amount of the virus genetic material present 7, compare it to a set of standards and express it as ‘genome equivalents (GE)’.
Many of the bees tested this year contained ~103 (i.e. 1000) GE, which is extremely low. Bees from Varroa-free regions (e.g. Colonsay) carry similar levels of DWV.
Most of our colonies were at or close to this level of virus much of the 2018 season. This is 100-1,000 times lower than we often see even in apparently perfectly healthy colonies in other years or other apiaries.
For comparison, using the same assay we usually detect about 1010 (ten billion) DWV GE per bee in symptomatic adult bees from heavily mite-infested colonies.
So, less mites means less viruses which means healthier bees 🙂
And they might even be happier bees 😉
And your point is?
It’s worth remembering that the purpose of treating a colony with miticides is to reduce the transmission of viruses between bees. This transmission results in the amplification of DWV. This is why the timing of treatments is so important.
Yes, it’s always good to slaughter a few (or a few thousand 🙂 ) mites. However, far better massacre them when you need to protect particular populations of bees.
This includes the overwintering bees, raised in September, that get the colony through to the Spring.
Remember also that it ‘takes bees to make bees’ i.e. the rearing of new brood requires bees. Therefore strong colony build-up in Spring requires healthy workers rearing healthy brood.
This is why it’s important to minimise mite levels in midwinter when colonies are broodless.
Whatever the vapoholics on the online forums claim, trickling remains the easiest, quickest and least expensive way to treat colonies in midwinter 8.
The best time to treat in the winter is when the colony is broodless. Here in Fife, and often elsewhere, I believe that this usually occurs earlier in the winter than many beekeepers treat (if it happens at all … or if they treat at all).
I usually treat between the end of the third week in November and mid-December, at the end of the first extended cold period.
Oxalic acid preparation recipe page views
Looking at the page views for these oxalic acid recipes it looks as though many beekeepers treat after Christmas 9 … which may be suboptimal if colonies had a broodless period and now started rearing brood again.
This winter has been quite mild (at least at the time of writing) so there may yet be opportunities to treat really effectively during a broodless period.
In draughty church halls the length and breadth of the country potential apiarists are just starting their “Beginning beekeeping” courses run by local associations. The content of these courses varies a bit but usually contains (in no particular order):
The Beekeeping Year
The hive and/or beekeeping equipment
The life cycle of the honey bee
Pests and diseases
Swarm prevention and control
Products of the hive
I’ve seen these courses from both sides. I took one before I started beekeeping and I’ve subsequently taught on them.
Although I’m not convinced the seven topics above are the optimal way to cover the basics of beekeeping (perhaps that’s something for a future post?), I am a strong supporter of the need to educate new beekeepers.
Theory and practice
You can learn some of the theoretical aspects of beekeeping on dark winter evenings. In my experience a liberal supply of tea and digestives hugely helps this learning process 😉
However, beekeeping is essentially a practical subject and any responsible association will offer apiary-based training sessions once the season starts. A good association will run these throughout the season, enabling beginners to experience all aspects of the beekeeping year.
If they don’t, they should (both run them and run them through the season).
The reason is simple … ‘hands on’ with the bees is a much better way of appreciating some of the most important characteristics of the colony. It’s strength and temperament, the rate at which it’s developing, the levels of stores etc.
But all this takes time. A couple of early-season apiary sessions might be held on cool evenings in failing light, or dodging Spring weekend showers. This means that ‘hive time’ is often restricted and beginners only get a small snapshot of the beekeeping season.
Curb your enthusiasm
Inevitably, many new beekeepers are desperate to get their own bees as soon as possible. After all, the season has started and there are kilograms of nectar out there waiting to be collected and converted into delicious honey for friends and family.
Demand for overwintered nucs is very high (usually significantly outstripping supply, meaning a considerable price premium) and a purchased colony, which should be strong and building up fast, becomes the property of someone who potentially has yet to see an open hive.
The seasonal nature of the hobby and the way we train beginners creates a very steep learning curve for new beekeepers 1. Almost as soon as they’re out of the classroom (or draughty church hall) they’re faced with the start of their first swarm season.
Queen cells …
Their inevitable – and completely understandable – enthusiasm to start practical beekeeping reaches a crescendo at a time when they are singularly poorly equipped to manage the colony 2.
The emphasis on the theory and practical aspects of beekeeping is understandable. There’s a lot to learn in a relatively short time.
However, this focus on the practicalities often overlooks emphasising the responsibilities of beekeepers.
In the frenetic early-season enthusiasm to ‘become a beekeeper’ these might seem unimportant, superfluous or entirely obvious.
But they’re not.
Oil seed rape (OSR) …
Later in the season the colony can become bad tempered, unmanageably large or ignored. Some or all of these happen with new (and not-so-new) beekeepers. The OSR goes over and colonies get stroppy, April’s 5-frame nuc “explodes” to occupy a towering double brood monstrosity or a new-found enthusiasm for dahlias or crown green bowls becomes all-consuming.
Bees? What bees? Have you seen my dahlias?
This is when the responsibilities of beekeepers become really important.
What are the responsibilities of beekeepers?
As I see it, as beekeepers we have responsibilities to:
As I stated above, these might seem entirely obvious. However, every year new beekeepers start with the best of intentions but some have a near-total lack of awareness of what these responsibilities are (or mean).
However, strange as it may seem to a beekeeper, some people are terrified of bees (mellisophobics). Others, due to adverse allergic reactions (anaphylactic shock), may have their lives endangered by bee stings. Finally – and thankfully by far the largest group – are the remainder of the public who should never feel bothered or threatened by our bees, whether we consider this a rational response or not.
What does this mean in terms of practical beekeeping? I think it can be distilled to just three points:
Keep calm bees
Keep bees and the public well-separated
Restrict beekeeping activities to times when the public are not inconvenienced
The first point is sensible, whether or not there’s anyone else around. It makes beekeeping a much more relaxing and rewarding experience.
The second point involves either keeping bees in unfrequented locations (infinitely preferable) or ensuring that bees are forced to fly up and away from the hives (by suitable screening) and well-away from passers-by.
The final point is the most inconvenient, but also the most important. If there are members of the public around who might be bothered by your bees – walkers strolling across the field towards your apiary, kids playing in the garden next door – don’t open the hives.
My apiaries have generally been in large rural gardens, private farmland and very well screened. I’ve also kept bees in urban environments, with no problems from the neighbours. However, I have always maintained out apiaries to move my bees to should they exhibit poor temper. Additionally, I’d only conduct inspections when the adjacent gardens were empty … meaning inspections were often carried out in sub-optimal weather or late in the evening.
Finally, while many beekeepers consider the sight of a swarm is one of the truly great sights of beekeeping, this isn’t a sentiment shared by most non-beekeepers.
Swarm on a swing … not ideal if it’s in the next door garden
The responsibilities beekeepers have to other beekeepers are probably restricted to:
The first is straightforward. Don’t do things that negatively impact other beekeepers 4. For example, don’t plonk two dozen hives over the fence from an established apiary, unless you’ve first discussed it with the beekeeper and you’re both happy that the local forage is sufficient.
Disease is perhaps less obvious and more insidious. The health of your bees influences the health of other colonies in the area. Over short distances bees drift from one hive to another. Over much longer distances strong colonies can rob weaker colonies.
All these bee exchanges also move the parasites and diseases they carry between hives. This includes Varroa, Nosema, a panoply of pathogenic viruses and European and American foulbrood.
Of these, the foulbroods are statutory notifiable diseases and beekeepers are legally required to report suspected diseased colonies under the Bee Diseases and Pests Control Order 2006 (and amendments). Responsible beekeepers will register their apiaries on the National Bee Unit’s Beebase so they are notified of local outbreaks, and so the bee inspectors can check their colonies if there is a nearby outbreak.
National Bee Unit Beebase
Whilst not notifiable, the remaining parasites and pathogens are also best avoided … and certainly should not be foisted upon other local beekeepers.
If your colony is weak, disease-riddled and poorly managed it may get robbed-out by other local strong colonies. In doing so, your bees will transfer (some of) the pathogen load to the stronger colony.
That is irresponsible beekeeping.
US beekeepers use the term ‘mite bomb’ to refer to an unmanaged, Varroa-riddled, collapsing colony that introduces significantly higher mite levels to local strong colonies as it’s robbed. This is more extreme, but not dissimilar, to beekeepers that treat with miticides far too late in the season. Their colonies retain high mite levels and can spread them to nearby hives. One way to avoid this is to coordinately treat mites in the same geographic area.
Bees may or may not be classified as livestock. The standard definition 6 of “domestic animals kept on a farm for use or profit; esp. cattle, sheep, and pigs” is perhaps a little restrictive 7 so lets accept for the moment that they are livestock.
If you keep livestock you usually need to register them and vaccinate them, and you always need to look after their health, feed and transport them properly and generally take responsibility for them.
Of course, bees are invertebrates, not mammals or animals with backbones. Legally invertebrates are not usually considered as animals in the Animal Welfare Act 20068 which defines the law on animal welfare.
But all these definitions are a distraction.
In my view, if you keep bees you have a responsibility to look after them properly.
Even if this isn’t a legal requirement, its a moral responsibility.
This responsibility to your bees includes – but is not restricted to – preventing and treating them for disease when appropriate and ensuring they have sufficient stores going into winter (and during periods with no nectar).
If you work abroad for April and May or if you holiday on the Maldives for six weeks every autumn you’re unlikely to become a successful beekeeper.
Bees? What bees? They’ll be OK …
And you’re certainly unlikely to be a responsible beekeeper.
You might start with bees, but you’re unlikely to keep them …
What prompted this post? A combination of things … cabin fever and online discussion forum posts from beekeepers puzzling why their colonies all died (no mite treatment, ever) or starved (no feeding before winter) or hadn’t been inspected in the last 15 months (“I’ve been busy”).
It was a good year here in Fife, with more of everything; more snow, more colonies, more honey (much more honey 🙂 ), more sheds, more wasps, more swarms and more deadVarroa.
Actually, the ‘more dead mites’ isn’t quite correct but I’ll return to that later.
The Beast from the East
There’s not much to say about the winter, but as we moved from February into March Storm Emma (also called the Beast from the East) arrived. The wind whipped the snow across the Howe of Fife (the largely flat centre of the county), dumping large drifts whenever it eddied over hedges or buildings. I had to dig us out of the house and the road from the village was impassable for 2-3 days.
The Beast from the East …
The colonies were all snug, if not warm, and weathered the storm without mishap. The reality is that if colonies are properly prepared for winter there’s almost nothing to do – or nothing you can do – until the weather picks up again in the Spring.
During the early part of the year I finished preparing our new bee shed. The bees were installed at the very end of March, soon followed by installation of a solar lighting system.
As I write this (early December 2018) the old apiary site has recently been bulldozed flat to make way for a new road. The contractors felled most of the beautiful trees in the well-established arboretum that surrounded the apiary.
All that’s left now is a muddy, ugly scar across the landscape waiting to be tarmac’d. Every time I drive past the line from The Last Resort by The Eagles, “Some rich men come and raped the land”, comes to mind.
That’s progress 🙁
On a slightly brighter note, we did save the original shed and it’s recently been reassembled on the new apiary site. This will provide some much needed storage space. The new shed is bigger, but still a bit cramped when used for storage, work and bees.
In like a lion, out like a lamb
Well, almost. March continued cold but the weather had picked up by mid-April. I’d lost just two colonies in the winter, both due to failed queens. By the third week of April I’d started inspections1 and colonies were all looking pretty good.
The weather got better and better, the oil seed rape (OSR) flowered and the bees started hammering it. Only one of my apiaries had OSR in range and they did really well.
Capped honey super frame …
By the middle of June the OSR was over and the honey was all extracted. The high glucose content of OSR nectar means it crystallises fast and very hard. It needs to be extracted before this happens in the frames. Some find OSR honey rather bland or an acquired taste. However, I’ve just processed the first couple of buckets into soft set honey and it’s excellent on toast.
The June gap
In terms of beekeeping it was non-stop. June was frantically busy. Even before the the Spring honey was off the crowded colonies had started to make preparations for swarming.
Just as the bees were preparing to move house I was also busy moving into a new house. It was manic. As fast as I put split boards into colonies more queen cells would appear. I started to run out of frames and brood boxes. I managed to hold some colonies back by slicing out great slabs of drone comb. This takes just a few seconds using foundationless frames and gives the bees something to do rather than make swarm preparations.
And in between all this I was interminably packing, driving and unpacking rental vans doing my own move.
I know I lost a couple of swarms – from about 20 colonies in total 2 – which left me feeling a bit guilty. At least they left with very low Varroa levels so, for a time at least, they would not contribute to the mite levels in the local environment. To ‘compensate’ for colonies that might establish themselves somewhere unwanted I donned my beesuit and destroyed a huge wasps nest in a neighbours roof space.
I also gratefully received a good-sized swarm in a bait hive.
The ‘June gap’ refers to the dearth of nectar that often occurs at this time of year. This year – despite excellent weather – was no exception. I didn’t feed colonies but many around me did. A few were a bit light but were OK until the summer flow started … which it did in late June or early July.
The flow must go on
Lime, blackberry, clover, rosebay willow herb and goodness knows what else. It was excellent. Coupled with continued good weather, hives got taller and taller as more supers were added. I ran out of supers altogether.
The good weather also aided queen mating which helped with requeening and preparing nucs for overwintering. About 75% of my colonies were requeened this year, almost all through splits of one type of another.
And then it was all over
The flow eventually stopped and the extraction was interminable. Not that I’m complaining. Super after super after super looked like this:
Ready to extract …
Wasps were a big problem in late summer. I lost a queenless colony and a nuc to the stripey blighters. Amazingly I managed to save the queen from the nuc 3 and she’s now heading a strong colony through the winter.
After a fortnight or so tidying, stock-taking (uniting colonies, cleaning cleared supers, making up a few additional nucs) and ‘final’ inspections it was time to start Varroa treatment and feeding colonies up for winter.
I’ve deliberately finished the season with fewer colonies than I started, but with more overwintering nucleus colonies for sale or making up losses. The absence of a work/life balance means I want to reduce my personal colony numbers by about a third for the next couple of years (to ~10), with another 6-8 overwintering for work. I’ll still be busy 🙁
Mite levels have been extraordinarily low this season. For work we uncapped many hundreds to low thousands of individual pupae 4 and found no more than half a dozen mites all season. We’ve seen no evidence of DWV symptoms and irregular mite counts on the Varroa trays have yielded very low numbers.
All colonies were treated by sublimation with an oxalic acid-containing treatment in early September, with three applications at five day intervals. The mite drop was so low (<200 from eight colonies in total in one apiary) that I was concerned that the treatment had failed. I therefore followed it up with Apivar strips in half the colonies. One or two additional dead mites appeared, but that was all.
So, not more deadVarroa, but probably a much greater proportion of the mite population were killed.
The Apiarist in 2018
This is the 300th post over the last five years. Yes, I’m surprised as well. I missed only one Friday when my hosting service was either not hosting or not providing a service 🙁
A few weeks ago I moved the site to a cloud-based virtual server (Amazon LightSail) which, to me at least 5 appears faster and more stable. Processor load is 10% what it was and page response times seem much better. Tell me if it isn’t.
Unique visitor numbers and page reads continue to increase year on year with both up ~33% on last year. What is particularly reassuring is that articles I’ve written on disease management now feature as the most read over the course of the year (though several were written in previous years). The ‘top five’ are:
When to treat? – the importance of correctly timing the early autumn Varroa treatment.
What less appropriate time is there, as we enter the festive season of goodwill, to provide a brief account of the incestuous and disease-riddled life cycle of the Varroa mite?
Happy Christmas 🙂
Scanning electron micrograph of Varroa destructor
Varroa is the biggest enemy of bees, beekeepers and beekeeping. During the replication cycle the mite transfers a smorgasbord of viruses to developing pupae. One of these viruses, deformed wing virus (DWV), although well-tolerated in the absence of Varroa1, replicates to devastatingly high levels and is pathogenic when transferred by the mite.
Without colony management methods to control Varroa, mite and virus replication will eventually kill the colony.
I’ve written extensively on ways to control Varroa. Most of these have focused on early autumn and midwinter treatment regimes. However, next season I’m hoping to discuss some alternative strategies and will need to reference aspects of the life cycle of Varroa … hence this post.
What is Varroa?
Varroa destructor is a distant relative of spiders, both being members of the class Arachnida … the joint-legged invertebrates (arthropods). It was originally (and remains) an external parasite (ectoparasite) of Apis cerana (the Eastern honey bee) and – following cross-species transfer a century or so ago – Apis mellifera, ‘our’ Western honey bee.
Apiscerana, having co-evolved with Varroa, has a number of strategies to minimise the detrimental consequences of being parasitised by the mite.
One hundred years is the blink of an eye in evolutionary terms and, whilst there are bees that have partial solutions – largely behavioural (small colonies and very swarmy) – they’re probably unable to collect meaningful amounts of honey 3.
Varroa-resistant honey bees will probably evolve (as much as anything is predictable in evolution) but not in my time as a beekeeper … or possibly not until Voyager 2 leaves the Oort Cloud4.
And there’s no guarantee they’ll be any use whatsoever for beekeeping …
The replication cycle of Varroa
Varroa has no free-living stage during the life-cycle. The adult mated female mite exhibits two distinct phases during the life-cycle. It has a phoretic phase on adult bees and a reproductive phase within sealed (‘capped’) worker and drone brood cells. Male mites only ever exist within sealed brood cells.
I’m going to discuss phoretic mites in a separate post. I’ll concentrate here on the replication cycle.
The mated female mite enters a cell 15-50 hours before brood capping. Drone brood is chosen preferentially (at ~10-fold greater rates than worker brood) and entered earlier. Depending upon the time of the season and the levels of mites and brood, up to 70-90% of mites in the colony occupy capped cells.
The first egg is laid ~70 hours after cell capping. This egg is unfertilized and develops into a haploid male mite. Subsequent eggs are fertilised, diploid, and so develop into female mites. These are laid at ~30 hour intervals.
The replication cycle of Varroa
Worker and drone brood take different times to develop. Therefore a typical reproductive cycle involves five eggs being laid in worker brood and six in drone brood. Not all of these eggs mature, their development being curtailed by the bee emerging as an adult.
There are all sorts of developmental stages involved in getting from an egg to a mature unfertilised mite, but these are not important in terms of the overall outcome. Mite-geeks love this sort of detail 5, but we need to cut to the chase …
Keeping it in the family
The foundress ‘mother’ mite and her progeny all share a single feeding hole through the cuticle of the developing pupa.
What a lovely scene of family ‘togetherness’.
Male and female mites take 6.6 and 5.8 days respectively to develop to sexual maturity. Therefore the male mite reaches sexual maturity before the first of his sisters.
He then lurks around the attractive-sounding “faecal accumulation site” and mates with each of the (sister) females in turn.
What a little charmer 😉
Male mites are short lived and the eclosion of the adult worker or drone curtails further mating activity, releasing the foundress mite and the mated mature daughters 6.
Reproductive rate (mites per cell)
The three day difference in the duration of worker and drone development means that more mites are produced from drone cells than worker cells. Depending on conditions the reproductive rate is 1.3 – 1.45 in worker brood and 2.2 – 2.6 in drone brood.
Remember that the foundress is also released from the cell. She can go on to initiate one or two further reproductive cycles (or up to 7 in vitro). Consequently, the average yield of mature, mated female mites from worker and drone cells is a fraction over 2 and 3 respectively.
Before entering a fresh cell containing a late stage (5th instar) larva the newly-mated mites need to mature. They do this during the phoretic phase which lasts 5-11 days. Therefore the full replication cycle of the mite probably takes a minimum of about 17 days.
Two to three mites per infested cell doesn’t sound very much. However, under ideal conditions this leads to exponential growth of the mite population in the colony. Assuming 10 reproductive cycles in 6 months, a single mite would generate a population of >1,000 in worker brood and >59,000 in drone brood 7.
Fortunately (for our bees, not for the mites), ideal conditions don’t actually occur in reality.
Lots of things contribute to the reduction in reproductive potential. For example, only 60% of male mites achieve sexual maturity due to developmental mortality, drone brood is only available at certain times in the season, brood breaks interrupt the availability of any suitable brood and grooming helps rid adult bees of phoretic mites.
Out, damn’d mite …
However, these reductions aren’t enough. Without proper management mite levels still reach dangerously high levels, threatening the long-term viability of the colony.
In the next few months I will discuss some additional opportunities for reducing the mite population.
In the meantime, as we reach the winter solstice, colonies in temperate regions may well be broodless and – as emphasised last week – this is an ideal time to apply a midwinter oxalic acid-containing treatment. This will effectively reduce mite levels for the start of the coming season.
Happy Christmas … unless you’re a mite 😉
Today is the winter solstice in the Northern hemisphere. This is actually the precise time when the Earth’s Northern pole has its maximum tilt away from the Sun. However, the term is usually used for the day with the shortest period of daylight and the longest period of night. In Fife, sunrise is at 08.44 and sunset at 15.37, meaning the day length is 6 hours and 53 minutes long.
With increasing day length queens will start laying again … but there’s a long way to go until winter is over.
It’s cold and dark and all is quiet in the apiary. Hives appear somnolent. Colonies are clustered 1 and, other than the odd corpse or two on the landing board, I’ve not seen a bee for at least a fortnight.
The apiary in winter …
Based upon previous experience I suspect colonies are – or very soon will be – broodless. I usually reckon that the first extended (2-3 weeks) period of cold weather 2 in the winter is the most likely time for the colony to be broodless.
Early autumn treatment protects the winter bees but also leaves the long autumn for the residual mites to continue replicating.
And there will be residual mites. No treatment is 100% effective.
So, paradoxically, if you treated early enough in the autumn to really help protect the winter bees, your mite levels will be higher at the end of the year.
Which also means they’ll be higher at the beginning of next year.
Not a good start to the 2019 season 🙁
Convenience or laziness?
Many beekeepers, for convenience, laziness or historical precedent, choose to apply the winter OA treatment between Christmas and New Year. I suspect that this is often too late. If the queen starts laying again around the winter solstice there will be sealed brood – and therefore unreachable Varroa – by the end of the month.
I’d prefer to have a cold and damp afternoon in the apiary slaughtering Varroanow than the convenience of treating them less effectively during the Christmas holiday period.
The latter might be more convenient … the office will be closed, I’ll be replete with turkey and sprouts and it will be a good excuse to ‘escape’ visiting relatives and yet more mince pies 4.
But is it the best time for your bees?
We have the technology
We have a couple of hives with Arnia hive monitors fitted 5. These have a temperature probe inserted into the brood nest. Brood rearing temperature is around 34°C. Here is a trace of one colony over the last month.
Arnia hive monitor temperature
The colony temperature was pretty stable (around 33-35°C) until about the 19th of November and has dropped about 10°C since then. Although I’ve not opened the colony I think that this is additional evidence that the colony is broodless 6.
Beekeeping by numbers
Keeping bees properly involves being aware of the seasons, the available forage and the state of the colony. This varies from month to month and year to year 7.
You can’t mechanically (‘by the numbers’) add supers on the 5th of May and harvest honey on the 15th of June. Sure, it might work some years, but is it the best time to do it?
Similarly, you can’t optimally treat a colony for Varroa on the 30th of December unless the climatic conditions and state of the colony coincide to make that the best time to treat.
It might be, but I suspect that generally it’s a bit late if there is a brood break.
If you’re going to the trouble of preparing the OA treatment, donning the beesuit and disturbing the colony you might as well do it at the right time for the bees.
I’ll be treating in between the predicted sleet showers and sunny periods this weekend.
Time to treat
Isn’t evolution a wonderful thing? This post started with a working title of “Know your enemy” and was on a different topic altogether. I’ll save that for next week.
The above was written at the beginning of the week. Now the weekend is closer it’s clear the weather is going to be cold with heavy snow predicted. Unless the forecast is wrong (and how often does that happen?!) I’ll hold off treating until a) it’s over 5°C, and b) the roads are safe.