Synopsis : Weather, nucs, queens, swarms and wax. A potpourri of topics that have entertained me while waiting for the heather flow to start … if it starts.
Maybe it’s old age 1 but the calendar seems to be speeding up these days. The dawn chorus is just a chirrup or two, there are mushrooms appearing everywhere, and I can sense the end of the season galloping towards me.
Or, maybe this is just a bit of a weird season.
It barely seems to have got started before it feels like it’s about to end.
The peak swarming period in my part(s) of Scotland has long gone 2 and the ‘June gap’ didn’t really happen, perhaps because the summer flowers started early. It’s now late July and the lime and blackberry are over. There’s some rosebay willow herb left, though not much and the heather has yet to properly start.
Erratic, just flowering heather
These are the summer doldrums; the time between the end of swarming and taking the summer honey off. It’s a relatively quiet time for my beekeeping. It’s too late (in Scotland, at least in my experience) for dependable queen rearing and it’s too early for any serious winter preparations.
There’s no longer a need to conduct weekly colony inspections. I’m reasonably confident that my colonies won’t swarm now, though I expect a few might supersede 3.
That doesn’t mean they won’t swarm … it just means my confidence might be misplaced 😉 .
Of course, that doesn’t mean that there’s no beekeeping to do … it’s just that I’ve got a little more time to complete what I need to do, and a bit of spare time to do a few other related activities.
Synopsis : Where should bait hives be located to capture your own lost swarms? 1 Can you omit the old brood frame and still make the bait hive attractive?
Social media can be seriously misleading for beekeepers. For months now it seems like I’ve been reading about boxes bulging with bees, third supers being added, swarms swarming and the oil seed rape bonanza.
With luck they’ve resisted the temptation to go rummaging through the brood box. Twice, because they didn’t see the queen on the first run through. Or the second. Should they buy another queen ’just in case’? 3
Old lags, by contrast, give a resigned shrug knowing that the season will be along in due course.
There’s nothing to be gained by trying to force things. Why open the box, why search for the queen, why risk chilling the bees and brood? There’s pollen going in on the few days good enough for flying, the water carriers are water carrying, the hive has stores (or you’ve quickly added a kilo or two of fondant under the crownboard) and things are progressing much as they should be … though definitely not in lockstep with events reported by the Twitterati in warmer climes.
Honeyguides are a group of 17 species of birds, distributed into four genera, belonging to the family Indicatoridae. All of the 8 species that have been well studied are brood parasites, like the cuckoo (Cuculus canorus). They lay their eggs in the nest of another species – usually a specific species as they are evolutionarily adapted to match the egg size and shape 1 – and subsequently puncture the other eggs to destroy the developing embryo.
There’s some great research on the evolutionary arms race between the egg puncturing ability of honeyguides and the eggshell thickness of the host species 2 … but I’ll leave that as your homework for the holidays 3 as I want to discuss something else about honeyguides.
Indicatoridae by name, indicator by nature
The really remarkable thing about honeyguides is hinted at by the family name.
This reflects their ability to lead human honey hunters to a wild honey bee nest site.
Of the 17 species of honeyguides, it is only the greater honeyguide (Indicator indicator) that has been extensively studied for its guiding behaviour. There is disagreement whether the scaly-throated honeyguide also exhibits similar guiding activity.
For the rest of this post, when I say ‘honeyguide’ I mean the greater honeyguide.
The greater honeyguide lives in dry open woodland in sub-Saharan Africa. It is a rather dull-coloured, starling-sized bird. It eats honey bee larvae, pupae and wax from the nest, and is one of the few birds that can digest wax.
However, the honeyguide cannot access most wild honey bee nest sites. These are often in a hollow tree and are well-defended by the bees.
But, over millenia, the honeyguide has learned that honey hunters, who have the benefit of being able to use smoke to calm the bees 4, leave a lot of debris after robbing the nest of honey.
And, over millenia, the honeyguide and honey hunters have evolved a mutualistic relationship in which the bird guides the human to the bee’s nest. The hunter gets the honey (and probably pupae, an important source of protein) and the honeyguide gets the leftovers.
“Mutualism describes the ecological interaction between two or more species where each species has a net benefit.”
Everybody wins 🙂
Greater honeyguides are territorial and scout out the location of wild bee nests in their territory. Each territory may contain multiple honey bee nests.
To attract the attention of a honey hunter the honeyguide emits a distinctive chattering call 5.
They then flit from tree to tree, towards the honey bee nest, perching and spreading the tail to expose two conspicuous white spots.
This behaviour was reported as long ago as 1588. João dos Santos, a Portuguese missionary, described the ability of the bird to lead honey hunters to bees’ nests (and also described how the bird would enter the church to eat the wax candles).
Guiding by honeyguides is very effective.
The honey hunters have learned to recognise the distinctive call, flight and perching activity of the bird 6. Studies have shown that ~75% of guiding events lead to the successful identification of at least one nest. 95% of these were honey bees nests and the remainder were stingless bees.
Smoke ’em out
Once the nest has been located the honey hunter uses smoke to calm the bees. Often the nests are located high up in the tree so the hunters attach some smouldering wood to a long pole and hold it near the nest entrance. They can then climb the tree and approach safely.
There are no bee suits or veils used … many of the photographs of honey hunters I’ve seen show them wearing just sandals and shorts.
The entrance is widened with a machete and the honey-laden combs are extracted intact and lowered to the ground … no doubt after a little ‘quality control’.
It’s not just humans who value honey … chimpanzees love the stuff as well, but they eat less than 1% of the honey consumed by humans in the same area. Chimpanzees, although known to use tools, do not know how to exploit fire. They are therefore ineffective honey hunters.
In a multi-year study of chimps in the Kibale National Park, Uganda, about 60% of of bees’ nests were successfully defended by the bees, driving the chimps away by stinging them. In contrast, human honey hunters are never driven away after smoking the nest.
Smoke is the key component needed for successful robbing of the nest by the honey hunters.
Two way communication
So, the honeyguide signals – with calls and its characteristic behaviour – to the honey hunter, guiding them to the nest site. The honey hunter can ‘read’ and understand these signals and can accurately home in on the nest.
But what if you are a honey hunter and, as you start your foraging, there are no honeyguides to be seen or heard?
This is where the close relationship between the honeyguide and the honey hunter becomes even more extraordinary.
The honey hunter calls to attract the honeyguide.
Not just any call, but a specific call … and to add an additional level of complexity, different tribes use different specific calls to attract honeyguides.
Remember, these are wild birds.
We’re all used to communicating with domesticated animals … “Here Fido!” 7, but a specific call to attract a wild animal is probably unique.
The Yao honey hunters in Mozambique use a distinct ‘brrrr-hm’ call to summon the honeyguide.
An excellent study by Claire Spottiswoode and colleagues showed that this call, not used by the Yao people for anything else, more than doubled the likelihood of attracting a honeyguide to the honey hunter and initiating guiding by the honeyguide 8. The call successfully attracted a honeyguide about two-thirds of the time it was used.
The characteristic ‘brrrr-hm’ call is passed down the generations of Yao honey hunters – from father to son 9 – meaning that a bird hearing the call could be reasonably certain the caller has the skills and tools necessary to harvest the honey.
Learning the lingo
Not all honey hunters use the same call. The Hadza people of northern Tanzania use a melodious whistle to attract honeyguides. The Kenyan Boran people use a distinctive sharp whistling call.
Different geographic populations of honeyguides clearly recognise distinct calls by the hunters.
How do the birds learn to recognise the call of the honey hunter?
Obviously not from their biological parents.
Remember, these are brood parasites and they are reared by other species such as lesser bee eaters or green woodhoopoes.
And there’s another amazing story here as these hosts have different shaped eggs 10. Different lineages of honeyguide have evolved that lay a suitably shaped egg that matches that of the specific host 11. The host specialisation is thought to reside on the female-specific W chromosome.
OK … enough digression.
It appears that honeyguides have an innate ability to recognise human calls. As young birds they listen for these calls and learn them, a process presumably reinforced through successful honey hunting in concert with humans.
Whether juvenile Tanzanian honeyguides transported to Kenya or Mozambique could identify the ‘local’ honey hunter’s call has not been tested, but would be interesting. I wouldn’t be surprised if the call used by the honey hunter has not also evolved (the evolution of languages is itself a fascinating area) to be distinctive from other sounds in the particular area, or to carry longer distances … or that is more attractive to the honeyguides.
The evolution of mutualism between humans and honeyguides
How did humans learn to call and follow honeyguides?
Originally it was thought to involve copying the natural guiding by the bird of honey badgers (ratels).
Mellivora capensis – the honey badger.
However, this story has largely been discredited – ratels do not call to attract the honeyguide and there’s a suspicion that videos showing birds guiding badgers have been staged 12.
Instead, it is much more likely that the mutualistic relationship between humans and honeyguides evolved over a very long period.
Since we’re talking about evolutionary timeframes here this could potentially mean millions of years.
Have humans been about that long?
No … we are the ‘new kids on the block’. Homo sapiens evolved from our hominin ancestors about 300,000 years ago. Therefore it’s likely that early hominins such as the (relatively recent) H. heidelbergenesis (0.4 million years ago (Mya) ), H. erectus (1.6 Mya) or H. habilis (2 Mya) were involved instead.
The divergence of humans and great apes from a common ancestor
Have honeyguides been about that long?
Yes … analysis of the mitochondrial DNA (inherited solely from the mother) of those distinct burrow- or tree-nesting lineages of honeyguides demonstrated that they diverged at least 3 million years ago.
Have honey bees been around that long?
Certainly … Apis mellifera probably evolved from other cavity-nesting bees about 6 Mya 13
There’s no smoke without fire
One of the great debates about the evolution of humans is when our ancestors learnt to create and use fire.
There is good evidence for use of fire about 1 Mya and additional claims that evidence control of fire 1.7 – 2 Mya 14.
All of which provides ample time for the evolution of mutualistic behaviour between H. erectus and the greater honeyguide.
This behaviour cannot have evolved without the ability of early hominins to control fire. The study of chimpanzees failing to successfully and efficiently collect honey shows this must be the case.
At least 44 distinct African ethnic groups exhibit the type of mutualistic relationship with honeyguides I have described and current studies are aimed at determining when the hominin-honeyguide mutualism evolved 15.
A honey hunting scene at Abrigo de Barranco Gómez in Castellote, Teruel, Spain c. 7500 years old.
The fossil record cannot help us here. There’s also a huge gap between the evolution of the early homonins and the upper Paleolithic rock art that clearly depicts honey hunters smoking bees’ nests.
More studies are needed. However the inexorable passage of time is now accompanied by increasing urbanisation, the availability of refined sugar and exclusion of hunter gatherers from nature reserves. This means that people depend less on honeyguides.
In time I expect it will be inevitable that this wonderful example of interspecies cooperation will be lost.
As another year draws to a close and you spread honey on your breakfast toast, take a moment to marvel at how our ancestors’ love of honey resulted in the evolution of the only known mutually beneficial relationship between a wild bird and humans.
The greater honeyguide is unique: it is the only wild animal that has been proven to selectively interpret human language. Brett Westwood tells the sweet story of a bird that leads human honey hunters to wild bees’ nests in order to share the rewards – perhaps one of the oldest cultural partnerships between humans and other animals on Earth. With biologist Claire Spottiswoode, anthropologist Brian Wood, and honey hunters, Lazaro Hamusikili in Zambia and Orlando Yassene in Mozambique, and the calls of the honeyguide. Producer: Tim Dee.
One of the great things about beekeeping as a hobby is that you are never short of gifts for friends and family 1. A jar or two of honey instead of a bottle of wine – or in addition to a bottle of wine – for dinner parties is always received with enthusiasm.
In your first year or two of beekeeping honey might not be available in excess. You get caught out by swarming or you lose the colony through poor mite management.
However, with a little more attention to swarm prevention / control and timely application of miticides your colony strength increases. Your colony numbers also probably increase. Together these, coupled with favourable weather and a geographically well-sited apiary, ensure a good honey crop.
You’ll never again be short of a last minute gift 🙂
But bees don’t only produce honey
With increasing hive numbers you will also start producing surplus wax. Bits of brace comb, wax cappings or wax melted out in a steam wax extractor … it all starts to add up.
Oops … brace comb
Before you know it you’ve got a few kilograms of wax and you need to find something creative to do with it.
Or uncreative … the simplest solution is to trade it in for fresh foundation 2. The block shown above has been filtered through a sheet of kitchen paper and is reasonably clean. In my experience, the wax doesn’t need to be anything like this clean to still be acceptable for exchange.
Of course, the obvious thing to do with excess wax is to make candles.
You need good quantities of nice quality wax, a bain-marie, moulds, wicks and significantly more skill than I’ve got 3. It’s also useful to have a very understanding and patient spouse … there will be spillages 🙁
Alternatively, with relatively little wax you can easily make beeswax wraps to seal food – or food containers – in the fridge or for lunches.
‘The eco-friendly, plastic free, alternative to clingfilm’.
That’s how Thorne’s advertises the beeswax wraps they sell. At two for about £13 (24 cm square) or three for £6 (12 cm square) they are not inexpensive … and when you see how easy they are to make yourself you’ll a) be gobsmacked/impressed 4 at the profit margin and, b) want to make some yourself for use or gifting.
We’ve been using commercial (a gift, in a coals to Newcastle way, from a non-beekeeper) or homemade wraps for at least a year now. The ones I have made are at least as good as the commercial ones, though they don’t come in the nice brown recycled packaging 5.
If you get your skates on you probably have sufficient time to prepare these before Christmas for last minute, in person, gifts.
If I’d written this a month or two ago you’d have also had time to post them – and they’re ideal for this for obvious reasons – but the last posting date 6 for Christmas was probably in October 🙁
The wraps are beeswax-impregnated cotton fabric of some sort. I’ve used plain or patterned cotton of a variety of colours. Depending upon the quality of the wax the material will discolour slightly, so it usually helps to have an off-white colour to start with.
I’ve no idea of the density or weight of the fabric. For comparison, I’d say it was similar to sheets or pillowcases.
Fabric and pinking shears
The beeswax is prepared with jojoba oil (to provide some antibacterial properties), almond oil (to increase pliability) and powdered pine rosin (to provide the ‘tack’ or stickiness).
You’ll need the following:
Cotton fabric cut into suitably-sized pieces. Use pinking shears to generate a run-free edge.
The pine rosin (the left-overs from turpentine distillation from pine resin) is usually sold in yellow to amber-coloured translucent lumps. Before use it needs to be ground into a powder. I use a pestle and mortar but I suspect you could do a much faster job with a coffee grinder 8.
In addition to the ingredients above you will also need a limited amount of additional ‘equipment’:
some means of melting the ingredients and holding them at temperature. A slow cooker is ideal for this purpose though you could also do this in a homemade bain-marie (e.g. a pyrex bowl in a saucepan of water over a low and controllable heat). Wax is flammable. Take care.
Slow cooker …
a metal oven tray and an oven to put it in.
a dedicated poor quality paintbrush. ‘Dedicated’ as it will be useless for anything else afterwards. ‘Poor quality’ as we’re not discussing fine art here … it’s just for spreading the melted stuff evenly over the fabric.
disposable wooden stirring sticks (lolly sticks, or similar).
Evenly spread the beeswax mix
Add the powdered pine rosin to the slow cooker and allow it to melt with occasional stirring. I set my slow cooker on medium heat for this.
Add the remaining ingredients to the melted rosin. I weigh the oils and add the solid wax and allow everything to melt together with more gentle stirring.
Pre-warm the oven to ~125°C.
When the mix is ready place the metal oven tray covered with a sheet of baking parchment and the first piece of pre-cut fabric in the oven for a couple of minutes.
Place the pre-warmed metal tray and fabric on a heatproof and newspaper-covered surface 9 and ‘paint’ the fabric with the beeswax mix. To reduce drips from the paintbrush I use an old coffee scoop to add the beeswax mix to the fabric and then spread it evenly with the paintbrush.
Put the tray and coated fabric back in the oven for two minutes.
Remove again and use the paintbrush to ensure the beeswax mix is spread evenly, with no lumpy bits or excess. This usually involves using the paintbrush to sort of spread the excess off to the sides 10.
Lift the now covered fabric wrap by two corners and hold over the metal tray (not the floor!) for 15 seconds or so to catch any drips. Remember, it’s likely to still be hot. Use tongs of some sort if you have heat-sensitive fingers.
Lay the finished wrap aside once it is sufficiently cool. This takes just a few seconds. You’ll often see instructions to hang these on a drying rack but I’ve never bothered.
Add another piece of fabric and go back to #4 in these instructions. Repeat until you’ve run out of beeswax mix, fabric or patience.
Here are some I prepared earlier
Once cooled they can be folded gently and stored.
The quantities by weight in the ingredients list above are sufficient to make (at least) a couple of dozen wraps 11. If that’s more than you need, or if you want to prepare the beeswax mix in bulk in advance, simply pour it into a suitable container (e.g. a plastic ice cream tub) that has been pre-treated with something like FloPlast Silicone Spray to allow its easy removal for re-melting.
You can make large wraps suitable for a loaf of bread in the same way. Just fold the fabric over so that it fits onto the metal tray. Turn it over to ensure that the fabric is full impregnated with the beeswax mix.
I found the recipe above somewhere online. I tried a couple and this worked best for me 12.
The wraps I make are a little thicker and quite a bit ‘tackier’ than the commercial ones I’ve seen.
I’m using tacky here as an adjective meaning ‘sticky’ … not as the informal ‘poor taste or quality’ !
This tackiness is an advantage as it is a little more self-adhesive when you’re wrapping things, and it probably makes the wrap last a little longer as well. You could probably reduce the rosin content to make a ‘drier’ beeswax wrap, but I can’t guarantee it will stay wrapped.
The same sorts of guidance applies to the use of these wraps as any commercial ones. Do not use them to wrap raw meat or fish. If they get dirty wash them in lukewarm water with a very small amount of detergent. If they lose their ‘stick’ revitalise them by placing them in the over for 5 minutes at 125°C.
Have fun 🙂
Elaine Robinson, a regular reader and commenter, sent me a description of an alternative way of preparing and applying the beeswax mix. Having mixed the ingredients she pours it onto a wetted piece of plywood where it sets in a thin sheet.
Preparing this sheets of beeswax wrap mix
Having floated this off in water she freezes it – or them as it makes sense to prepare a lot in advance – in a tub and then, by simply shaking the tub, turns it into broken shards.
Here are some that were prepared earlier – sheets of beeswax wrap mix
Using about 16 g of shards per 30 cm square wrap Elaine stacks the fabric and shards on a baking tray and places them in an oven at ~80°C.
Ready to use shards – use them straight from the freezer to avoid stickiness
After melting everything all that is then needed is a brush to ensure the edges of each of the beeswax wraps are fully covered … followed by folding the wraps and popping them into some very neat custom-made brown paper sleeves that she also prints at home.
Which look very impressive and made my efforts look rather inadequate 😉
A question following a recent evening talk to a beekeeping association prompted me to look back at the literature on amitraz and wax residues.
The question was about reuse of honey supers that were present on a colony during miticide treatment.
With the exception of MAQS, there are no approved miticides that should be used if there are honey supers on the hives. The primary reason for this is that there is a risk that the miticide will taint the honey. Since the latter is for human consumption this is very undesirable.
However, it’s not unusual at the end of the season to have a half empty super, or a super containing just uncapped stores. Typically this would be ‘nadired’ i.e. placed below the brood box, with the expectation that the bees will move the stores up into the brood chamber 1.
Two colonies overwintering with nadired supers
And sometimes this super remains in place during the annual early autumn Varroa slaughter.
The question was something like “Can I reuse the honey super next season?”
As anyone who has heard me speak will know, my answer was probably rambling, repetitive and slightly incoherent 🙁
However, the gist of it was “Yes, but I don’t”.
With Zoom talks and written questions from the audience you often don’t get all the details. The answer must be sufficiently generic to cover most eventualities 2 including, for example, the range of possible miticides that were used for treatment.
Assuming the nadired super is emptied by the bees during the winter, what are the chances that the wax comb will be contaminated with miticides?
This depends upon the miticide used.
I explained that the organic acids (formic or oxalic) are not wax soluble and so the super can be reused without a problem.
In contrast, Apistan (a pyrethroid) is known to be wax soluble, so it should probably not be used again to avoid any risk of tainting honey subsequently extracted from it 3.
Instead, it reflected a dim memory of some posts I’d read earlier in the year on the Bee-L discussion forum. This is a low volume/high quality forum frequented by scientifically-inclined beekeepers.
It turns out that, although amitraz (the active ingredient in Apivar) is not wax soluble, it’s broken down (hydrolysed) to a formamide and a formamidine.
Read that again … I didn’t write the same word twice 😉
The formamide has no residual activity against mites. In contrast, the formamidine retains miticidal activity and is wax soluble.
Is this a problem?
Well, possibly. One of the things discussed by Richard Cryberg on Bee-L was that there appears to be no toxicology data on these two products. It’s probably been done, just not published.
Perhaps we can assume that they’re not hideously toxic to humans (or bees)? If it was, amitraz (which is the active ingredient in all sorts of mite and tick treatments, not solely for bees) would carry sterner warnings.
Or should 🙁
The residual miticide activity is potentially more of a problem. A well understood route to developing miticide resistance involves long-term exposure to sub-lethal doses. There are several reports of amitraz resistance in the scientific literature, and bee farmers are increasingly providing anecdotal accounts of resistance becoming a problem.
This, and the possibility of tainting honey, are reason enough in my opinion to not reuse drawn supers that have been on the hive (e.g. nadired) during Apivar treatment.
But it turns out that there are additional potential issues with amitraz residues in comb.
Miticide residues in wax
Commercial wax foundation – like the stuff you buy from Thorne’s or Maisemores or Kemble Bee Supplies – is often contaminated with miticide residues. A large US survey of drawn comb from hives and foundation demonstrated that:
Almost all comb and foundation wax samples (98%) were contaminated with … fluvalinate 4 and coumaphos 5, and lower amounts of amitraz degradates and chlorothalonil6, with an average of 6 pesticide detections per sample and a high of 39.
I’m not aware of an equivalent published analysis of UK foundation. I’m know one has been done and I’d be astounded if it produced dramatically different results. There’s a global trade in beeswax, some of which will be turned into foundation. The only exception might be certified organic foundations.
A freshly drawn foundationless frame
I always purchase premium quality foundation but am under no misapprehension that it doesn’t also contain a cocktail of contaminants, including miticides and their ‘degredates’.
I’d be delighted to be proved wrong but, since I think that’s unlikely, it’s one reason I use an increasing number of foundationless frames … which also saves quite a bit of cash 🙂
Drones and queens and miticides in wax
Numerous studies have looked at the influence of miticide residues on worker, drone and queen development. These include:
Sublethal doses of miticides can delay larval development and adult emergence, and reduce longevity 7
Tau-fluvalinate- or coumaphos-exposed queens are smaller and have shorter lifespans 8
Queens reared in wax-coated cups contaminated with tau-fluvalinate, coumaphos or amitraz attracted smaller worker retinues and had lower egg-laying rates 9.
Drones exposed to tau-fluvalinate, coumaphos or amitraz during development had reduced sperm viability 10.
All of which is a bit depressing 🙁
These studies used what are termed ‘field-realistic’ concentrations of the contaminating miticide. They didn’t use wax saturated in miticide, but instead contaminated it with parts per million (ppm), or parts per billion (ppb).
These are the highest concentrations reported in surveys of comb tested in commercial beekeeping operations in the US, so hopefully represent a ‘worst case scenario’.
It’s also worth noting that some commercial beekeepers in the US use significantly more – both in amount and frequency – miticides than are used by amateurs. If you read American Bee Journal or the Beesource forums it’s not unusual to find accounts of spring, mid-season, late-summer and mid-winter treatments, often of the same colonies.
To add to the literature above, a new paper was published in November 2020 which suggested that amitraz residues in wax increased the mating frequency of queens.
The paper is by Walsh et al., (2020) Elevated Mating Frequency in Honey Bee (Hymenoptera: Apidae) Queens Exposed to the Miticide Amitraz During Development. Annals of the Entomological Society of America doi: 10.1093/aesa/saaa041
This piqued my interest. Queen mating frequency is an important determinant of colony fitness.
If a queen mates with more drones there’s inevitably increased genetic diversity in the colony and, in landmark studies by Thomas Seeley, an increase in colony fitness 11.
Colony fitness includes all sorts of important characteristics – disease resistance, foraging ability, overwintering success etc.
So, perhaps this is a benefit of amitraz residues in your wax foundation … the reduced egg-laying rate being compensated by increased patrilines 12 and a fitter colony?
Walsh and colleagues grafted queens into JzBz queen cups containing wax laced with one or more miticides. They reared the queens in ‘cell builders’ that had not been miticide treated, shifted mature queen cells to mating nucs and then – after successful mating – quantified two things:
the viability of spermatozoa in the queen’s spermatheca
the mating frequency of the queen
Irrespective of the miticides incorporated into the wax lining the queen cup, sperm viability was very high (98.8 – 99.5% viable), and no different from queens not exposed to miticides during development.
Queen cells after emergence in mating nucs
This suggests that miticide contamination of queen cells is unlikely to have a deleterious effect on sperm viability in mated queens.
However, rather oddly, this contradicts a not dissimilar study 5 years ago from some of the same authors where the presence of tau-fluvalinate and coumaphos didreduce sperm viability 13, as did an earlier study looking at the effect of amitraz 14.
This contradiction is pretty-much ignored in the paper … clearly something that “needs further investigation”.
It might be due to experimental differences (for example, they used different methods to determine sperm viability). Alternatively, since the queens were open-mated, it might reflect differences in the miticide-exposure of the donor drones.
The authors used microsatellite analysis to determine the mating frequency of the queens reared during the study. They compared queens reared in the presence of amitraz or tasty cocktails of tau-fluvalinate & coumaphos, or clorothalonil & chlorpyrifos 15, with those reared in the absence of chemicals contaminating the waxed queen cup.
They measured the observed mating frequency and then calculated the effective mating frequency (me). Conveniently they describe the difference between these parameters:
The observed mating frequency refers to the total number of drone fathers represented in a queen’s worker progeny. The effective mating frequency uses the proportion of each subfamily within a colony and compensates for calculating potentially skewed estimates of paternity (i.e., unequal subfamily proportions in sampled pupae) and intracolony genetic relatedness.
‘Convenient’ because it saves me having to explain it 😉
The observed mating frequencies of the control queens (untreated wax), or those reared in the presence of amitraz or tau-fluvalinate & coumaphos cocktails were not statistically different. However, queens reared in clorothalonil & chlorpyrifos-laced wax had a lower observed mating frequency.
Strikingly though, when calculated, the effective mating frequency of amitraz- or tau-fluvalinate & coumaphos-exposed developing queens was significantly higher (~12.9-13.4) than either the untreated controls or clorothalonil & chlorpyrifos (~8.2-8.8) 16.
And … ?
The amitraz result is new.
The influence of tau-fluvalinate & coumaphos on effective mating frequencies has been reported previously (by some of the same authors 17) which, since this was a new study in a different region, is at least encouraging because it supports the earlier work.
Taken together, these results suggest that miticide residues (of at least two chemically different types) increase the number of drones that a queen mates with.
The discussion of the paper speculates about why this difference is observed.
The number of drones a queen mates with is influenced by several things. These include the number and duration of the mating flights. Perhaps the amitraz-exposed queen can’t count properly, or loses her ability to judge time … or just flies more slowly?
All of these would result in exposure to more drones.
Before returning to the hive, a queen must be able to determine whether she has mated with sufficient drones. It is suggested that stretch receptors in the oviducts are involved with this, forming a negative feedback stimulus once the oviducts are full. Perhaps amitraz impairs stretch receptor function or signalling?
Clearly there’s a lot left to learn.
The effective mating frequencies determined in the presence of amitraz (and tau-fluvalinate & coumaphos) were higher than the controls. However, they still appear rather low when compared with previous reports of hyperpolyandrous 18 colonies with up to 77 distinct patrilines (I’ve written about this previously, including descriptions of how it was determined).
Don’t mix the two observations up. In the studies of hyperpolyandry they analysed queens to determine their patriline.
A queen from a very rare patriline is still a queen, so can be screened.
In contrast, if you only screen a handful of workers (from the thousands present in the colony), you are very unlikely to find extremely rare patrilines. Those you do find will be the ones that are most common.
A logical extension of the studies reported by Walsh et al., would be to determine whether hyperpolyandry also increased in amitraz-exposed colonies. If the effective mating number is increased you should observe a larger number of patrilines.
Alternatively, perhaps Withrow and Tarpy (who published the hyperpolyandry paper 19) should look again at whether the colonies they screened had a long history of amitraz exposure.
And what about that nadired super?
It’s probably fortunate I’d not fully read the literature before answering the question after my talk.
If I had, I’d have tried to paraphrase the ~2000 words I’ve just written … so making my answer interminably long.
Of course, it’s unlikely that an amitraz (Apivar) contaminated super will ever be visited by a queen (but these things do happen 🙁 ).
Or be a location for developing queen cells.
So, in this regard, I think it’s irrelevant whether the super is reused.
In contrast, the wax solubility and residual miticide activity of one of the hydrolysis products of amitraz is more of a concern. I don’t want this near honey I’m going to extract, and I’d rather not have it in the hive at all.
All of which explains the “Yes, but I don’t” answer to the original question about whether the super can be reused.
Fondant feeding on a colony with a nadired super
The super in the picture above will be removed early next season, before the queen starts laying in it. The super will be empty and I’ll melt the wax out in my steam wax extractor.
In a good nectar flow the bees will draw a full super of comb very quickly. Yes, they’ll use some nectar that would otherwise be used make honey, but that’s a small penalty.
And since this is what many beekeepers do it explains why I’m certain that most commercial foundation is contaminated with miticides 🙁
But don’t forget …
Mite management is important. Miticides are chemicals and, like other medicines, have both beneficial and detrimental effects. The beneficial effects far outweigh the detrimental ones. If you do not treat, the likelihood is that mites and viruses will kill the colony … if not immediately, then eventually.