Category Archives: Beekeeping

Tough love

Synopsis : ‘Nature knows best’ sometimes doesn’t apply to your bees and a responsible beekeeper must intervene with a little tough love to rescue the situation.

Introduction

Beekeeping involves quite a lot of responsibility. It’s not a ’fit and forget’ pastime. You need to think about others that you (and your bees) share the environment with.

Or, at least, you should.

If you want an apiary in your small urban garden you need to consider the impact it will have on the neighbours. If your colony develops American foul brood you have a responsibility to inform the local bee inspector who will notify the National Bee Unit. They, in due course, send one of those dreaded 1 ‘Foulbrood Alert’ emails to other registered beekeepers in the immediate area.

But your responsibilities don’t end with the civilians (i.e. non-beekeepers) and beekeepers around you.

Common carder bee

Arguably they also apply to the other pollinators your bees will be competing with in the environment. Will a quarter of a million generalists (your bees) threaten the survival of the – often more specialised – local solitary or bumble bees? 2

And, just when you thought I’d run out of responsibilities to remind you about, there’s the responsibility you have to your bees.

They’re not pets, they’re not domesticated, but they are at least partially dependent upon us. For shelter, for food (at times) and for their health and wellbeing.

And that sometimes means beekeepers have to take tough decisions …

Tough love

The phrase tough love was coined by Bill Millikan in his 1968 book of the same title. It’s usually taken to mean the ’act of treating a [person] sternly or harshly with the intent to help them in the long run.’

I put ‘person’ in brackets because – on a beekeeping blog – I’m talk about bees.

Although some beekeepers love to dabble with their colonies, the reality is that – for the most part and for much of the season – they do a pretty good job of looking after themselves.

Our interventions are really for our benefit – checking for queen cells so the workforce doesn’t vamoose, adding supers etc.

However, things can go wrong. Either we mess up, or there’s some bad weather or bad luck or bad karma. Whatever the cause, the colony may be left in a state in which their long-term survival becomes much less certain. At that point the beekeeper may have to – or should – make a pragmatic decision that resolves the situation.

And that decision may have to involve some ‘tough love’.

Not intervening may risk the total loss of the colony. Intervening, even though it may involve some sacrifices, may well save the colony.

Frosty apiary

Frosty apiary

This topic is timely as we’re reaching that point of the year where active beekeeping must stop and the, seemingly-interminable, off-season starts. Colonies that look in a precarious state now may well not make it through to the spring. Indeed, if they look really precarious now, they might not survive the first few frosts.

However, similar pragmatic interventions may be needed at other times of the season. In the following paragraphs I’ll illustrate a few scenarios and possible solutions.

Failed queens

The queen is, or should be (!), the longest-lived bee in the colony. Many live a couple of seasons, and some significantly longer.

But all good things must come to an end, and at some point she’ll run out of sperm, or enthusiasm or whatever. Usually the colony realises things are amiss well before the beekeeper and, quietly and efficiently, stages a bloodless coup and supersedes her.

A lot of supersedure happens in late summer and early autumn. The first you know of it is that you find an unmarked and unclipped queen the following spring.

Very late season virgin queens

‘Very late’ is a subjective term and depends on your latitude, the number of drones that are still about and the weather. Here in Scotland my colonies have been turfing out drones for almost a month and it’s already feeling quite autumnal. Further south things might be very different.

If you do find a virgin queen scampering about the hive (very) late in the season you have a dilemma. Do you cross your fingers and hope she gets mated in the next few days, or do you accept that it’s unlikely, sacrifice her and unite the colony.

Many beekeepers do the former.

Ever the optimist …

But let’s be realistic for a minute. How long since the queen emerged? If the weather has been poor for a fortnight she might already be going a bit ’stale’ (and if the weather has been poor you can be pretty certain that drone numbers in the area will be seriously depleted).

Is there a good chance she can get out in the weather predicted in the next week? And is there then sufficient time for her to lay enough brood to populate the colony with good numbers of winter bees that will ensure its viability until spring?

If she’s already ageing, if the weather is a bit dodgy, or if there’s any real doubt about the chances of success, I would always sacrifice the queen and unite the remaining bees in the colony with a nearby strong colony.

Yes … she might get mated … but if she doesn’t the colony is doomed.

Late season cast swarms fall into the same category, except they already may contain too few bees to rear lots of autumn brood.

Very early season queen failures

Sometimes – though rarely – you find a colony with a failed or failing queen very early in the season. I barely ever see these as I’m not usually opening boxes until mid/late April, but I know some beekeepers are busy at least 4-6 weeks before that.

It’s too early in the year to have any queens of your own and an overwintered queen will cost megabucks. Adding a frame of eggs/larvae is a non-starter … there are no drones yet.

But buying a new queen is unlikely to be satisfactory (aside from the megabucks that is). If the queen failed (or started failing) weeks ago – for example, she never started laying again properly after a few weeks off late the previous year – the colony will be dwindling fast and are unlikely to be strong enough to build up for the season ahead.

In my view buying a queen – or using one of your own – in this situation is not sensible. Cut your losses. Get rid of the queen if she’s still present and unite the remaining bees with another colony.

This isn’t even an example of tough love … it’s more just plain common sense and economically prudent 3.

Mid-season queen failures

Sometimes you find a colony with a really patchy brood pattern. Perhaps the queen is running out of sperm, or she’s very poorly mated (with only a small number of drones).

Patchy brood pattern

Patchy brood & QC’s …

However, in this instance it’s obvious to the beekeeper, but not necessarily obvious to the colony as they’re showing no signs of superseding her.

As an aside, it’s worth noting that there may be other reasons than a failing queen for a patchy brood pattern. A very strong nectar flow can often result in the workers backfilling cells within the brood nest … give them more supers. It’s also been reported that a spotty brood patten can be due to the colony, not the queen i.e. you transfer the queen to another colony and her laying pattern improves.

Again I’d argue that, whilst you could let events run their course, it is probably better to intervene and get things back on track. In this instance I’d cull the queen and requeen directly or unite the colony (if I was sure there was no disease). Alternatively, if I had no spare queens, I would leave them queenless for a week, knock back any/all the queen cells and add a frame of eggs from a ‘good’ colony in the hope – actually expectation – that they’d rear a better queen.

Why intervene? After all, there’s lots of the season left, the weather is good, there are ample drones about etc.

By intervening I’ve got reasonable certainty of the timing of things. If I let the bees make the decisions they might wait until very much later in the season … which takes us back to ’Very late season virgin queens’.

Laying workers

By definition, a colony with laying workers is queenless. Laying workers develop in the absence of pheromones produced by open brood (larvae).

The colony thinks it is queenright. Therefore, if you try and requeen it they usually kill the introduced queen.

Laying workers ...

Laying workers …

One solution is to add a frame of open brood to the colony, and then add another a few days later … and perhaps one more a bit later. The brood pheromone suppresses the laying workers in the hive 4 and, with a bit of luck, they will rear a new queen from the last frame of eggs/larvae you added.

But they might not. And if they don’t you will have to intervene or the colony will inevitably perish.

Don’t throw good brood after bad

Over the years I’ve more of less (because I still sometimes try!) learned that laying workers are a lost cause. The resources that must be invested – in time and in open brood – are insufficient to justify the success rate.

So, time for some tough love … I remove the colony from its stand and shake all of the bees off the frames in front of other strong colonies. I discard the frames and any brood they contain (this will almost all be bullet-shaped drone pupae in worker cells).

Frames showing the characteristic dispersed bullet brood of laying workers

The brood will perish as will some of the bees you shake out … but they were doomed anyway 5.

Do not unite a colony containing laying workers with a queenright colony. The former thinks it is queenright … that’s not going to end well. I would expect the queen in the recipient colony to be killed 6. For similar reasons, if I only had two hives and one had laying workers, you risk the queen in the ‘good’ hive if you shake them out.

Varroa-infested colonies in midseason

I’ve discussed this recently so will be brief.

If you have a colony heavily infested with mites in midseason (let’s not discuss why this happened) you could treat them with a suitable miticide, accepting that the treatment period is likely to be protracted and it may even preclude adding honey supers 7.

Remember, the majority of the mites will be busily munching on sealed brood. You either need to use a miticide that permeates the cappings – go back and read the last footnote – or you need to treat for at least a complete brood cycle (and usually longer).

A colony that has recently been subjected to a shook swarm

Alternatively, you can conduct a shook swarm on the colony and then treat with a vaporised (which would be my choice) or trickled oxalic acid-containing miticide like Api-Bioxal.

Divide and conquer

During a shook swarm you separate the adult bees (and the queen) from all the brood. The latter is discarded (that’s the tough love bit). Since you now only have adult bees and their phoretic mites you can, more easily, kill 95% of the mite population.

I’ve done this many times 8. The resulting colony builds up again really strongly and – most importantly – the Deformed wing virus levels remain low for the remainder of the season.

Again, by sacrificing the brood that carries the vast majority of the mites, the remainder of the colony is given a new lease of life and should flourish.

This approach needs either a good nectar flow or a gallon or three of thin syrup (and suitable weather for comb building). To build up quickly the colony must draw a full box of new comb. Give them every opportunity to do so.

Philosophy corner

In the examples above I’m suggesting sacrificing one component of the colony – the queen, the sealed brood etc. – to ‘save’ the rest of the bees.

Of course, I’m well aware that the individual bees in a colony only live a few short weeks. The queen is the exception and can live several years.

So, in the case of a late season virgin queen, if you sacrifice the queen the remaining bees are saved, but they’re going to perish pretty soon anyway (Stalin’s ‘A single death is a tragedy; a million deaths is a statistic.’ comes to mind – though he might not have said this anyway).

So, does it make any difference?

I’m outside my comfort zone here, but I think it does.

If you do nothing and the queen fails to mate the queenless colony will die overwinter. They’ll dwindle until the cluster is the size of an orange and then freeze to death … or something equally sad/tragic/heroic/pathetic/inevitable (take your pick).

If you intervene, remove the queen and unite them with another colony, the individual bees (you added) probably won’t make it through to the spring, but they will contribute to the strength – and therefore survival – of the colony you united them with. Their demise, whilst still inevitable, will have some benefit.

And what about sealed brood? 9 I think something reasonably similar applies. Varroa-exposed pupae will almost certainly die before or shortly after emergence anyway. High infestation levels – I’ve seen colonies with 20,000+ mites – mean the majority of the brood is probably doomed. I would therefore have few qualms about sacrificing the brood with the expectation of purging the colony of mites within a few days of the shook swarm.

Sustainable beekeeping

Michael Palmer titled one of his excellent talks The Sustainable Apiary. It is all about being self-reliant in your beekeeping. Don’t buy in queens, do overwinter nucs to make up for overwintering losses etc.

I think this sort of sustainability is a very worthwhile goal for a beekeeper. It means acquiring the skills to rear new queens (which doesn’t necessarily mean grafting, mini-nucs or any of that ’high tech’ stuff … it can be a whole lot simpler, yet extremely effective 10 ), to identify disease and treat according, and to manage colonies so that they remain strong and healthy.

But sustainability does not mean save everything at all costs. Significantly understrength colonies, failed or failing queens, laying workers etc. require some tough love so that your remaining colonies can thrive.

Overwintered virgin queen?

Overwintered virgin queen?

It’s worth remembering that a strong overwintered colony, that builds up well in spring, will almost always produce both a new nucleus colony and a honey crop. Rather than try and maintain a failing colony overwinter, investing time and resources (like frames of brood or bees to give it a spring ‘boost’) – remembering that it may well perish during the winter anyway – unite it in autumn and then split off a nuc during swarm control the following spring.

Everybody’s a winner 😉

The two hive beekeeper

If you only have one hive and it’s weak going into the winter, or the queen fails, or it develops laying workers, then almost all of the above isn’t going to help much. What’s more, if you’ve only got one hive, how can you tell that the colony is weaker than it should be?

It’s much easier to compare colonies in the same environment to determine if they are strong or weak.

Compare and contrast – much easier when you have something to compare with

This reinforces the importance of having at least two hives. If this was your first season I’d strongly recommend you aim to go into next winter with two strong colonies. If you’ve yet to start, remember that a single colony can reach a state in which it will inevitably perish, but you can almost always rescue things if you have a second hive 11.

As you embark on your last inspections of the season, don’t go into the winter with crossed fingers and a prayer for ’that little colony in the blue hive’ … it’s not too late to unite it with a neighbouring hive.

Don’t let it be a statistic … or a tragedy 😉


 

Biological control with Varroa

Synopsis : Honey bees were eradicated on Santa Cruz Island following the introduction of Varroa. This provides some useful lessons for beekeepers on the importance of controlling Varroa.

Introduction

Honey bees are not native to North America. They were first introduced in March 1622 at Jamestown, Virginia. The bees did well and spread west, following the settlers. They finally arrived on the west coast, in Santa Clara, California, 231 years later in 1853. Of a dozen hives ordered by Christopher Shelton, a Santa Clara botanist and rancher, only one survived the journey from New York via Panama.

Shelton barely had a chance to enjoy his bees 1 as he was unfortunately killed when the steamboat Jenny Lind exploded in mid-April 1853.

Explosion on the steamboat Jenny Lind near San Francisco, California

His bees survived 2 and three hives derived from the original stock were auctioned for $110 each. This was over 20 times the price of hives on the east coast at that time and equivalent to over $4200 today 3.

Californian Channel Islands map

Bees were in demand and they continued to spread – both as feral swarms and as farmers established apiaries to help pollination and for honey production. Having reached the California coast they were then spread to the nearby islands. Bees were transported to Santa Cruz, the largest of the eight Channel Islands near Los Angeles, in the 1880’s. They flourished, but did not spread to the other Channel Islands.

Field station, nature reserves, pigs and bees

Santa Cruz Island is 250 square kilometres in area and lies ~35 km south of Santa Barbara. It is one of the four Northern Channel islands. There is a long central valley lying approximately east-west and the rocky mountainous land reaches 740 m. It has a marine temperate climate; the average low and high temperatures are 9°C and 21°C respectively and it receives about 0.5 m of rain a year. It is a good environment for bees.

From the 1880’s to 1960’s Santa Cruz Island was farmed – primarily for wine and wool, and from the 1940’s for cattle – but, after period of university geology field trips and the establishment of a field station on the island, in 1973 it became part of the University of California’s Natural Reserve System (UC NRS).

In the late 1970’s the Stanton family sold their ranching business on the island to The Nature Conservancy who subsequently bought additional land on the eastern end of the island.

Santa Cruz Island is now jointly owned by The Nature Conservancy, National Parks Service, UC NRS and the Santa Cruz Island Foundation and much of the island is used for scientific research and education.

But what about the bees?

Good question.

As a nature reserve and research station, the presence of non-native species causes a potential problem. Why go to all the expense of managing a remote island research centre if all the same species are present as on the mainland?

The Nature Conservancy therefore initiated a programme of eradicating non-native species. It took 14 months to eliminate the feral pigs, using a combination of trapping, helicopter-based shooting and the release of sterilised radio-tagged pigs to locate the stragglers 4.

But getting rid of the bees took a bit longer …

Save the bees, or not

Why get rid of the bees? Surely they weren’t doing any harm?

The introduction of any non-native species upsets the balance (if there’s ever balance) in the ecosystem. The introduced species competes directly or indirectly with those native to the area and can lead to local extinctions.

Jonathan Rosen has described 5 how honey bee swarms, through occupying tree cavities previously used for nesting, probably played a major role in the extinction of the Carolina parakeet.

Pining for the fjords … a stuffed Carolina parakeet (nailed to its perch)

Competition between honey bees and native pollinators has been well studied. It is not always detrimental, but it certainly can be. Furthermore, it is probably more likely to be detrimental in a small, isolated, island ecosystem. For example, studies showed that the presence of honey bees dramatically reduced visitation of native pollinator to manzanita blossoms on Santa Cruz Island.

As part of the larger programme of non-native plant and animal eradication on Santa Cruz Island plans were drawn up in the late 1980’s to eliminate European honey bees. The expected benefits were to:

  • eliminate competition with native bee species (and presumably other non-bee pollinators, though these rarely get a mention 🙁 )
  • reduce pollination of weed species (some of which were also non-native to Santa Cruz Island)
  • facilitate recovery of native plant species that were reliant on native bee pollination
  • provide a ‘field laboratory’ free from ‘exotic’ honey bees in which comparative studies of native pollinators would be possible

Killer bees

After the plans to eradicate Apis mellifera were approved an additional potential benefit became apparent.

There were increasing concerns about the spread of Africanised honey bees which had recently reached Santa Barbara County. Although there was reasonably compelling evidence that swarms could not cross from the mainland (e.g. none of the other Northern Channel Islands had been colonised by bees) there were concerns that the Santa Ana winds might help blow drones from the mainland.

Had these drones arrived they might mate with the non-native but nevertheless local queens resulting in the spread of the dominant genes for defensiveness and absconding. The resulting swarmy, aggressive Africanised bees would cause problems for visitors and scientists working on the island (as they have for visitors to Joshua Tree National Park).

Aerial view of Santa Cruz Island

Although the introgression of African honey bee genes was used as further justification for the eradication it’s not clear whether drones could actually cross 30-40 km of open sea 6.

As an aside, there’s a current project – the amusingly named Game of Drones – running on the Isles of Scilly investigating whether drones can cross the sea between St Agnes, Tresco, Bryher, St Mary’s and St Martin’s. These are, at most, 11 km apart (northern most tip of St Martin’s to most southerly point of St Agnes) but the individual islands are only separated by 1-2 km. I would be surprised if drones could not cross that distance (at least with a strong following wind).

Killing bees

Adrian Wenner and colleagues set about exterminating the honey bees on Santa Cruz Island (Wenner et al., 2009). The process started in 1988 and ended in 2007, and was divided into four phases:

  1. 1988-1993 – location and elimination of feral colonies
  2. 1994-1997 – biological control and colony demise
  3. 1998-2004 – monitoring residual honey bee activity
  4. 2005-2007 – confirmation of the absence of honey bees

None of this is ’beekeeping’ – actually it’s the exact opposite – so I don’t intend to dwell in much detail on the work that was conducted. However, the ’94-’97 phase includes some sobering lessons for beekeepers which are worth discussing.

By the end of phase 1 the team had identified the existence (if not the location) of at least 200 colonies and eliminated 153 of them.

Remember, none of these were managed colonies in hives. They were all feral colonies occupying natural cavities in trees or rocks etc. Each colony was found using painstaking bee lining techniques similar to those described in Thomas Seeley’s book Following the Wild Bees.

Once located, nests were destroyed with methyl chloroform and the cavity sealed to prevent it being reoccupied.

Some colonies could not be accessed; in these cases acephate-laced sucrose-honey syrup baits were used. This organophosphate has delayed toxicity for bees, allowing foragers to return to the colony which in due course dies. This approach had been partially successful in eliminating Africanised bees on the mainland (Williams et al., 1989), but baits needed to be be monitored to avoid killing the other insects they attracted.

The scientists also deployed swarm traps (aka bait hives) and destroyed any swarms that moved in.

Together these interventions reduced honey bee numbers significantly – as monitored by regular observations at pollen- or nectar-rich plants – but did not eradicate them.

Let there be mite

Heavy rains in January ’93 washed out roads on Santa Cruz Island, thereby severely limiting travel around the island. In addition, the previous removal of cattle had resulted in the near-uncontrolled growth of fennel which now formed dense, impenetrable thickets.

Bee lining became impossible and the scientists had to invent more devious strategies to eliminate the residual feral colonies.

The approach they chose involved the introduction of Varroa.

Varroa was first detected in the USA in 1987 (in Florida) and became widespread over the next 5-8 years. Up until 1994 the honey bees on Santa Cruz Island were free of the ectoparasitic mite.

It was likely that they would have remained that way … there was no beekeeping on Santa Cruz Island and the location was too remote for bees to cross from the mainland (see above).

Varroa was already known to have a devastating impact on the health of honey bee colonies (Kraus and Page, 1995). It was also known that, other than its native host Apis cerana (the Eastern honey bee), Varroa did not parasitise other bee or wasp species (Kevan et al., 1991).

These two facts – host specificity and damage inflicted – suggested that Varroa could be used for biological control (‘biocontrol’) on Santa Cruz Island.

Biological control

Biological control or biocontrol is a method of controlling pests using natural mechanisms such as predation or parasitism.

The pest could be any living thing – from animals to bacterial plant diseases – present where it’s unwanted.

On Santa Cruz Island the pest was the honey bee.

In other studies (covered in a previous post entitled More from the fungi 7 ) biocontrol of Varroa has been investigated.

Control of the pest involves the introduction or application of a biological control agent. The key requirements of the latter have already been highlighted – specificity and damage.

Biological control works well when the specificity is high and the damage is therefore tightly targeted. It can be an abject failure – or worse, it can damage the ecosystem – if the specificity is low and/or the damage is widespread.

The cane toad was introduced to Australia to control infestations of greenback cane beetle (a pest of sugar cane). Cane toads were introduced in 1935 and rapidly spread. Unfortunately, cane toads can’t jump very high and so singularly failed to control the greenback cane beetle which tends to 8 stay high up the cane stems.

Female cane toad (not jumping)

But it gets worse; cane toads have a very catholic diet and so outcompeted other amphibians. They introduced foreign diseases to the native frogs and toads and – because of the poisons secreted from their skin – harmed or killed predators that attempted to eat them.

Oops.

Vertebrates are usually poor biological control agents as they tend to be generalist feeders i.e. no specificity.

But Varroa is specific and so the damage it causes is focused. The likelihood of ecosystem damage was considered low and so the mite was introduced to the island.

Introduction of Varroa

In late 1993 Adrian Wenner caught 85 foraging bees and, to each one, added a single Varroa mite. The bees were then released and presumably flew back to their colonies … taking the hitchhiking mite with them.

Adult mites – the dark red ones you see littering the Varroa tray after you treat with Apivar – are mated females.

Due to their incestuous lifestyle a single mite is sufficient to initiate a new infestation.

The mated adult female mite parasitises a honey bee pupa and produces a series of young; the first is male, the remainder are female. You’re probably reading this before the 9 pm watershed so I’ll leave it to your lurid imagination to work out what happens next (or you can read all the sordid details in Know your enemy).

The presence of honey bees – determined by successful swarm trapping or field observation at likely sites – was then regularly monitored over the next four years.

Swarm numbers remained largely unchanged until 1996 and then dramatically decreased.

Numbers of new swarms on Santa Cruz Island 1991 – 2005. Varroa introduction indicated.

It’s worth noting that during ’94-’96 over 70 swarms were found in natural sites or bait hives. There must have been a significant number of established colonies in 1993 to produce this number of swarms.

But, from 1997 it all stopped … only a single swarm was subsequently found, in a natural cavity in 2002.

Monitoring and confirmation of eradication

From 1998 to 2004 the scientists continued to actively monitor the island for honey bees, focusing on 19 areas rich in natural forage. Although honey bees were found – in decreasing numbers – there were too few to attempt bee lining to locate their colonies.

At the sites being monitored, bees were detected 9, 7, 4, 2 and 1 times respectively in the 5 years from 2000 to 2004. After that, despite continued monitoring, no more honey bees were detected.

The final phase of the project (’05-’07) confirmed the absence of honey bees on Santa Cruz Island.

Whilst, as a scientist, I’m a firm believer that ’absence of evidence does not mean evidence of absence’, as a beekeeper I’m well aware that if there are no scout bees, no swarms and no foragers (when I search in likely places) then there are no honey bee colonies.

Lessons for beekeepers

I wouldn’t have recounted this sorry tale – at least from a beekeeping perspective – unless I thought there were some useful lessons for beekeepers.

There are (at least) three.

The first relates to Varroa resistance, the second to Varroa transmission in the environment and the last to ‘safe’ levels of Varroa. All require some ‘arm waving guesstimates’ 9, but have a good grounding in other scientific studies.

Varroa resistance

There wasn’t any.

At a very conservative estimate there were at least 20 colonies remaining on Santa Cruz Island in 1995. I say ‘conservative’ because that assumes each colony generated two swarms that season (see graph above). In studies of other natural colonies only about 75% swarm annually, meaning the actual number of colonies could have been over 50.

The numbers – 20 or 50 – matter as they’re both much higher than the number of colonies most beekeepers manage (which, based upon BBKA quoted statistics, is about 5).

Whether it was 20 or 50, they were all eliminated following the introduction of 85 mites. Colonies did not become resistant to Varroa.

This all took a few years, but – inferring from the swarm numbers above – the vast majority of colonies were killed in just two years, 1994 and 1995. This timing would fit with numerous other studies of colony demise due to mites.

Wenner estimates that only 3 colonies survived until 2001.

Leaving small numbers of colonies 10 untreated with an expectation that resistance – or even tolerance (which is both more likely and not necessarily beneficial) – will arise is a futile exercise.

I’ve discussed this before … it’s a numbers game, and a handful of colonies isn’t enough.

Varroa spread

Wenner doesn’t elaborate on where the foragers were captured before he added the mites. If I was going to attempt this I’d have chosen several sites around the island to ensure as many feral colonies as possible acquired mites … let us assume that’s what he did.

However, with 85 mites piggybacking on returning workers, and somewhere between (my guesstimated) 20 to 50 colonies, I think it’s highly likely that at least some colonies received none of this ’founding’ mite population.

Yet almost all the colonies died within two years, and those that did not subsequently died with no further intervention from the scientists. We don’t know what killed off the last surviving colonies but — and I know I’m sticking my neck out here – I bet it was the mites.

This is compelling evidence for the spread of Varroa throughout the island environment, a process that occurs due to the activities of drifting and robbing.

If a neighbouring apiary to yours has mites some will end up in your hives … unless you are separated by several kilometres 11.

The transmission of mites in the environment is a very good reason to practice coordinated Varroa control.

One mite is all it takes

But, just as I’ve argued that some colonies may have received none of the founding mites, I’m equally sure that others will have acquired very small numbers of mites, perhaps just one.

And one mite is all it takes.

Without exceptional beekeeping skills, resistance in the bee population or rational Varroa control 12 there is no safe level of mites in a colony.

The more you prevent mites entering the colony in the first place, and the more of those that are present you eradicate, the better it is for your bees.

Here endeth the lesson 😉


Note

It’s worth noting that island populations do offer opportunities for the development of Varroa resistant (or tolerant) traits … if you start with enough colonies. Fries et al., (2006) describes the characteristics of the 13 surviving colonies on Gotland after leaving about 180 colonies untreated for several years. I’ve mentioned this previously and will return to it again to cover some related recent studies.

References

Fries, I., Imdorf, A. and Rosenkranz, P. (2006) ‘Survival of mite infested (Varroa destructor) honey bee (Apis mellifera) colonies in a Nordic climate’, Apidologie, 37(5), pp. 564–570. Available at: https://doi.org/10.1051/apido:2006031.

Kevan, P.G., Laverty, T.M. and Denmark, H.A. (1990) ‘Association of Varroa Jacobsoni with Organisms other than Honeybees and Implications for its Dispersal’, Bee World, 71(3), pp. 119–121. Available at: https://doi.org/10.1080/0005772X.1990.11099048.

Kraus, B. and Page, R.E. (1995) ‘Effect of Varroa jacobsoni (Mesostigmata: Varroidae) on feral Apis mellifera (Hymenoptera: Apidae) in California’, Environmental Entomology, 24(6), pp. 1473–1480. Available at: https://doi.org/10.1093/ee/24.6.1473.

Wenner, A.M., Thorp, R.W., and Barthell, J.F. (2009) ‘Biological control and eradication of feral honey bee colonies on Santa Cruz Island, California: A summary’, Proceedings of the 7th California Islands Symposium, pp. 327–335. Available as a PDF.

Williams, J.L., Danka, R.G. and Rinderer, T.E. (1989) ‘Baiting system for selective abatement of undesirable honey bees’, Apidologie, 20(2), pp. 175–179. Available at: https://doi.org/10.1051/apido:19890208.

 

Mellow fruitfulness

Synopsis : Final colony inspections and some thoughts on Apivar-contaminated supers, clearing dried supers, feeding fondant and John Keats’ beekeeping.

Introduction

The title of today’s post comes from the first line of the poem ’To Autumn’ by John Keats:

Season of mists and mellow fruitfulness

The poem was written just over 200 years ago and was the last major work by Keats (1795-1821) before he died of tuberculosis. Although it wasn’t received enthusiastically at the time, To Autumn is now one of the most highly regarded English poems.

The poem praises autumn, using the typically sensuous imagery of the Romantic poets, and describes the abundance of the season and the harvest as it transitions to winter.

That’s as maybe … the last few lines of the first verse raises some doubts about Keats’ beekeeping skills:

And still more, later flowers for the bees,
Until they think warm days will never cease,
 For summer has o’er-brimm’d their clammy cells.

It’s certainly true that there are late summer flowers that the bees can forage on 1. However, he’s probably mistaken in suggesting that the bees think in any sense that involves an appreciation of the future.

And what’s all this about clammy cells?

If there’s damp in the hive in late summer then it certainly doesn’t bode well for the winter ahead.

Clammy is now used mean damp; like vapour, perspiration or mist. The word was first used in this context in the mid-17th Century.

‘Clammy’ honey

But Keats is using an earlier meaning of ’clammy’ … in this case ’soft, moist and sticky; viscous, tenacious, adhesive’, which dates back to the late 14th-Century.

And anyone who has recently completed the honey harvest will be well aware of how apt that definition is 😉 … so maybe Keats was a beekeeper (with a broad vocabulary).

And gathering swallows twitter in the skies

That’s the last line of ’To Autumn’ (don’t worry … you’ve not inadvertently accessed the Poetry Please website). The swallows are gathering and, like most summer migrants, already moving south. Skeins of pink-footed geese have started arriving from Iceland and Greenland.

Skein of geese over Fife

My beekeeping over the last fortnight has been accompanied by the incessant, plaintive mewing of buzzards. These nest near my apiaries and the calling birds are almost certainly the young from this season.

A few nights ago, while hosing the extractor out in the bee-free-but-midge-filled late evening, I was serenaded by tawny owls as the adults evicted their young from the breeding territory in preparation for next season.

These are all signs, together with the early morning mists, that summer is slipping away and the autumn is gently arriving.

Morning mist clearing over the loch

The beekeeping season is effectively over and all that remains is preparing the colonies for winter.

Supers

All the supers were off by the 22nd of August. There was still a little bit of nectar being taken in but the majority was ripe and ready. As it turns out there was fresh nectar in all the colonies when I checked on the 10th of September, but in such small amounts – no more than half a frame – that it wouldn’t have been worth waiting for.

At some point you have to say … enough!

Or, this year, more than enough 🙂 .

Most of the honey was extracted by the end of August. It was a bonanza season with a very good spring, and an outstanding summer, crop. By some distance the best year I’ve had since returning to Scotland in 2015.

Of course, that also meant that there were more supers to extract and return and store for the winter ahead.

Lots of lifting, lots of extracting and lots of buckets … and in due course, lots of jarring.

Storing supers wet or dry?

In response to some recent questions on storing supers wet or dry I tested ‘drying’ some.

I’ve stored supers wet for several seasons. I think the bees ‘like’ the heady smell of honey when they are added back to the hives for the spring nectar flow. The supers store well and I’ve not had any problems with wax moth.

However, this year I have over two full carloads of supers, so – not having a trailer or a Toyota Hilux 2 – I have to make multiple trips back to put them in storage 3. These trips were a few days apart.

I added a stack of wet supers to a few hives on the 1st of September and cleared them on the 9th. All these supers were added over an empty super (being used as an eke to accommodate a half block of fondant – see below) topped with a crownboard with a small hole in it (no more than 2.5 cm in diameter, usually less).

Converting wet supers to dry supers – note the crownboard with a small central hole

When I removed the supers on the 10th they had been pretty well cleaned out by the bees. In one case the bottom super had a very small amount of fresh nectar in it.

So, 7-8 days should be sufficient for a strong colony to clean out 3-4 supers and it appears as though you can do it at the same time as feeding fondant … result 🙂 .

Feeding fondant

I only feed my colonies Baker’s fondant. I add this on the same day I remove the honey-laden supers. I’ve discussed fondant extensively here before and don’t intend to rehash the case for its use again.

Oh well, if you insist 😉 .

I can feed a colony in less than two minutes; unpacking the block, slicing it in half and placing it face down over a queen excluder (with an empty super as an eke) takes almost as much time to write as it does to do.

Take care with sharp knives … much easier with a slightly warm block of fondant

But speed isn’t the only advantage; I don’t need to purchase or store any special feeders (an Ashforth feeder costs £66 and will sit unused for 49 weeks of the year). I’ve also not risked slopping syrup about and so have avoided encouraging robbing bees or wasps.

I buy the fondant through my association. We paid £13 a block this year (up from about £11 last year). That’s more expensive than making or buying syrup (though not by much) and I don’t need to have buckets or whatever people use to store, transport and distribute syrup. Fondant has a long shelf life so I buy a quarter of a ton at a time and store what I don’t use.

All gone! 12.5 kg of fondant added on 22/8/22 and photographed on 9/9/22

And, contrary to what the naysayers claim, the bees take it down and store it very well.

What’s the biggest problem I’ve had using fondant?

The grief I get when I forget to return the breadknife I stole from the kitchen … 😉 .

Apivar-contaminated honey and supers

Last season I had to treat a colony with Apivar before the supers came off. This was one of our research colonies and we had to minimise mite levels before harvesting brood.

I’ve had a couple of questions recently on what to do with supers exposed to Apivar … this is what I’ve done/will do.

Apivar

The Apivar instructions state something like ’do not use when supers are present’ … I don’t have a set of instructions to check the precise wording (and can’t be bothered to search the labyrinthine VMD database).

Of course, you’re free to use Apivar whenever you want.

What those instructions mean is that honey collected if Apivar is in the hive will be ’tainted’ and must not be used for human consumption.

But, it’s OK for the bees 🙂 .

So, I didn’t extract my Apivar-exposed supers but instead I stored them – clearly labelled – protected from wasps, bees and mice.

This August, after removing the honey supers I added fondant to the colonies. In addition, I added an Apivar-exposed super underneath the very strongest colonies – between the floor and the lower brood box.

I’ll leave this super throughout the winter. The bees will either use the honey in situ or will move it up adjacent to the cluster.

In spring – if I get there early enough – the super will be empty.

If I’m late they may already be rearing brood in it 🙁 … not in itself a problem, other than it means I’m flirting with a ridiculous ’double brood and a half’.

Which, of course, is why I added it to the strongest double brood colonies. It’s very unlikely the queen will have laid up two complete boxes (above the nadired super) before I conduct the first inspection.

But what to do with the now-empty-but-Apivar-exposed supers?

It’s not clear from my interpretation of the Apivar instructions (that I currently can’t find) whether empty supers previously exposed to Apivar can be reused.

WARNING … my reading might be wrong. It states Apivar isn’t to be used when honey supers are on but, by inference, you can use and reuse brood frames that have been exposed to Apivar.

Could you extract honey from brood frames that have previously (i.e. distant, not immediate, past) been Apivar-exposed?

Some beekeepers might do this 4.

It’s at this point that some common sense it needed.

Just because re-using the miticide-exposed supers is not specifically outlawed 5 is it a good idea?

I don’t think it is.

Once the bees have emptied those supers I’ll melt the wax out and add fresh foundation before reusing them.

My justification goes something like this:

  • Although amitraz 6 isn’t wax-soluble a formamidine breakdown product of the miticide is. I have assumed that this contaminates the wax in the super.
  • I want to produce the highest quality honey. Of course this means great tasting. It also means things like wings, legs, dog hairs and miticides are excluded. I filter the honey to remove the bee bits, I don’t allow the puppies in the extracting room and I do not reuse supers exposed to miticides.
  • During a strong nectar flow bees draw fresh comb ‘for fun’. They’re desperate to have somewhere to store the stuff, so they’ll draw out comb in a new super very quickly. Yes, drawn comb is precious, but it’s also easy to replace.

Final inspections

I conducted final inspections of all my colonies in Fife last weekend 7.

For many of these colonies this was the first time they’d been opened since late July. By then most had had swarm control, many had been requeened and all were busy piling in the summer nectar.

Why disturb them?

The queen had space to lay, they weren’t likely to think about swarming again 8 and they were strong and healthy.

Midsummer inspections are hard work … lots of supers to lift.

If there’s no need then why do it?

Of course, some colonies were still busy requeening, or were being united or had some other reason that did necessitate a proper inspection … I don’t just abandon them 😉 .

I don’t just abandon them … introducing a queen to a nucleus colony

But now the supers were off it was important to check that the colonies were in a suitable state to go into the winter.

I take a lot of care over these final inspections as I want to be sure that the colony has the very best chance of surviving the winter. 

I check for overt disease, the amount of brood in all stages (BIAS; so determining if they are queenright) and the level of stores.

And, while I’m at it, I also try and avoid crushing the queen 🙁 .

Queenright?

I don’t have to see the queen. In fact, in most hives it’s almost impossible to see the queen because the box is packed with bees. If there are eggs present then the queen is present 9.

But, there might not be a whole lot of eggs to find.

Firstly, the queen is rapidly slowing down her egg laying rate. She’s not producing anything like 1500-2000 eggs per day by early autumn.

A National brood frame has ~3000 cells per side. If you find eggs equivalent in area to one side of a brood frame she’s laying at ~1000/day. By now it’s likely to be much less. At 500 eggs/day you can expect to find no more than half a frame of eggs in the hive.

Remember the steady-state 3:5:13 (or easier 1:2:4) ratio of eggs to larvae to pupae? 10

Several of my colonies had about half a frame of eggs but significantly more than four times that amount of sealed brood … clear evidence that the laying rate is slowing dramatically.

The shrinking brood nest – note the capped stores and a little space to lay in the centre of the frame

Secondly, the colony is rapidly filling the box with stores, so reducing the space she has to lay. They’re busy backfilling brood cells with nectar.

Look and ye shall find …

So I focus carefully on finding eggs. I gently blow onto the centre of the frames to move the bees aside and search for eggs.

In a couple of hives I was so focused on finding eggs that – as I prepared to return the frame to the colony – I only then saw the queen ambling around on the frame. D’oh!

Some colonies had only 3-4 frames of BIAS, others had lots more though guesstimating the precise area of brood is tricky because of the amount of backfilling taking place.

I still need to check my notes to determine whether it’s the younger queens that are still laying most eggs … I’d not be surprised.

Stores

Boxes are now heavy but not full. All received (at least) half a block of fondant in late August and more last weekend. There’s also a bit of late nectar. The initial half block was almost finished in a week.

Once the bag is empty I simply peel it away from the queen excluder. If you’re doing this, leave the surrounding super in place. It acts as a ‘funnel’ to keep the thousands of displaced bees in the hive rather than down your boots and all over the floor.

Although the bees were flying well, the bees in and around the super were pretty lethargic. I’ve seen this before and am not concerned. I don’t know whether these are bees gorged with stores, having a kip or perhaps young bees that don’t know their way about yet. However, it does mean that any bees dropped while removing the bag tend to wander aimlessly around on the ground.

I’d prefer they were in the hive, out of the way of my size 10’s.

If you look at many of the frames in the hive they will be partially or completely filled with stores. The outer frames are likely to be capped already. 

An outer frame of capped stores

These frames of stores are heavy. There’s no need to look through the entire box. I simply judge the weight of each frame and inspect any that are lighter than a full frame of stores.

Closer to the brood nest you’ll probably find a frame or two stuffed, wall-to-wall, with pollen. Again, a good sign of a healthy hive with the provisions it needs to rear the winter bees and make it to spring.

Disease

The only sign of disease I saw was a small amount of chalkbrood in one or two colonies. This is a perennial situation (it’s not really a problem) with some of my bees. Quite a few of my stocks have some (or a lot of) native Apis mellifera mellifera genes and these often have a bit of chalkbrood.

I also look for signs of overt deformed wing virus (DWV) damage to recently emerged workers. This is the most likely time of the year to see it as mite levels have been building all season and brood levels are decreasing fast. Therefore, developing brood is more likely to become infested and consequently develop symptoms.

Fortunately I didn’t see any signs of DWV damage and the initial impression following the first week or so of miticide treatment is that mite levels are very low this season. I’ll return to this topic once I’ve had a chance to do some proper counts after treating for at least 8-10 weeks (I use Apivar and, since my colonies all have medium to good levels of brood, the strips need to be present for more than the minimum recommended 6 weeks).

Closing up

Although these were the last hive inspections, they weren’t the last time I’ll be rummaging about in the brood box.

At some point during the period of miticide treatment I’ll reposition the strips (adjacent to the ever-shrinking brood nest) having scraped them to maximise their effectiveness.

Apivar scratch and sniff repositioning studies

However, all that will happen in a month or so when I can be reasonably sure the weather will be a lot less benign. Far better to get the inspections out of the way now, just in case.

So, having added the additional fondant (typically half a block) I closed the hives, strapped them up securely and let them get on with making their preparations for the coming winter.

Goodbye and thanks for the memories

There’s a poignancy about the last hive inspections of the season.

The weather was lovely, the colonies were strong and flying well, and the bees were wonderfully placid. It’s been a great season for honey, disease levels are low to negligible and queen rearing has gone well 11.

But it’s all over so soon 🙁 .

Hive #5 (pictured somewhere above … with the empty bag of fondant) was from a swarm control nuc made up on the last day of May (i.e. a 2021 queen). It was promoted to a full hive in mid-June. At the same time, while the hive they came from (#28) was requeening I’d taken more than 20 kg of spring honey from it. The requeening of #28 took longer than expected as the first was almost immediately superseded. Nevertheless, the two hives also produced almost 4 full supers (conservatively at least 40 kg) of summer honey.

Good times 🙂 .

My notes – for once – are comprehensive. Over the long, dark months ahead I’ll be able to sift through them to try and understand better 12 what went wrong.

That’s because – despite what I said in the opening paragraph of this section – there were inevitably any number of minor calamities and a couple of major snafu’s.

Or ’learning opportunities’ as I prefer to call them.

Last light over Rum and Eigg … not a bad view when visiting an out apiary

But that’s all for the future.

For the moment I have a sore back and aching fingers from extracting for days and the memory of a near-perfect final day of proper beekeeping.

It’s probably time I started building some frames 🙁


 

Making a beeline

Synopsis : Honey bees use a range of navigation skills including path integration – to shorten return flights – combined with map-like spatial memories to relocate the hive.

Introduction

Regular readers will be aware that I’m interested in the origins of words. The Oxford English Dictionary (OED) is a fantastic source of information and produces a free Word of the Day email 1. This includes both the meaning and etymology of one word each day.

Since the complete dictionary includes over 600,000 words it will take a few years to collate the 20 volumes that comprise the entire dictionary 2.

At the beginning of this week the word of the day was beeline.

The word beeline of course means:

A straight line or course, such as a bee follows in returning to its hive after having collected a full load of nectar; (occasionally) the course taken by a bee.

The word originated in the US almost 200 years ago. It was first recorded in the American Quarterly Review in June 1828. Anyone who has read Tom Seeley’s Following the Wild Bees will appreciate the context in which the word beeline was used:

The bee-hunter..encloses them [sc. bees] in a tube, and letting one fly, marks its course, by a pocket compass. Departing to some distance, at right angles to the bee-line just ascertained, he liberates another, observes its course, and thus determines the position of the hive, which lies in the angle made by the intersection of the bee-lines.

Beelining is the art of finding feral or wild colonies by following the returning flight of bees. The book has a companion website with some interesting videos if you’d like to know more.

Find and tell

Beelining ‘works’ because bees fly in a straight line back to the nest 3.

The basics of beelining

Assume the blue flowers above are nectar-rich and favoured by the bees. You capture a couple of bees feeding on the blue flowers and give them some additional syrup so that they are replete and need to return to the colony to unload.

When you release the bees at ‘A’ they fly at a particular bearing back to the colony. However, if you instead release them at ‘B’ they fly at a different compass bearing back to the colony.4  .

How did the bees find the nectar-rich blue flowers in the first place?

Perhaps they observed another worker in the colony performing the waggle dance which informed them of the angle (from the sun) and distance to the blue flowers?

Alternatively, they might have just been searching around and chanced upon the blue flowers … they didn’t know they were there in the first place.

If they found the blue flowers by interpreting the waggle dance then you should be thinking how the waggle dancing bee found the blue flowers.

Alternatively, if they found the blue flowers by chance then you should be wondering how they will communicate their location to other foragers in the colony.

Transient nectar sources

Nectar sources are transient. They yield at particular times of the year … and of the day. The nectar may be dependent on recent rainfall or a variety of other environmental conditions.

All this means is that foragers may have to search widely to find a good source of nectar. If the source is really good – ample sugar-rich nectar and with lots of flowers producing it – then it’s important that the forager that found it tells her half-sisters how to also quickly find the same source.

Foraging and finding

On the left the blue flowers have been yielding for days. The workers fly there in a straight line and return along the same path. Newly orientated workers observe the returning foragers waggle dancing and follow the same route to quickly and efficiently exploit the source.

But all good things come to an end …

On the right is what happens when blue flowers stop yielding. The foragers that arrive at the blue flowers find slim pickings and start casting about looking for a better source of nectar. They first find the marginally better yellow flowers, then the similar (but far from outstanding) purple flowers … so they keep looking.

And eventually, they find the red flowers. Lots of nectar and lots of flowers. They load up and return directly to the colony (black dotted line).

There are two striking things about this return flight. The first is that it does not follow (in reverse) the route by which they reached the red flowers. The second is that when these returning foragers perform the waggle dance they ‘instruct’ the observing bees to fly in the direction of the red dotted line … rather than to the blue, then yellow, then purple and then red flowers.

Path integration

The foragers who find the red flowers perform a process termed path integration to return:

Path integration is the process by which an animal, when moving away from a start point, often its nest, cumulatively sums its path, generating an internal vector that specifies the line from the animal’s current position back to the start point, however circuitous the outward trip (Collet, 2019).

This is a skill I singularly lack when trying to relocate my vehicle in the multi-storey car park.

Path integration is seen in other insects … Drosophila fruit flies can do it (over a range of centimetres), walking ants can do it over a range of hundreds of metres, and honey bees can do it over at least 5 kilometres (and probably more).

Path integration requires two pieces of information – the direction and the distance of travel.

Path integration – individual parts of the flight are in different directions and of different lengths

Clearly, the very existence of the waggle dance provides compelling evidence that bees are aware of both. The dancing forager reports the angle (relative to the sun) of the nectar source and the distance at that angle that must be covered before the nectar source is located.

But for path integration, not only must the angle and distances be determined, they must also be cumulatively summed.

Neurophysiology and evolutionary conservation

Detailed neurophysiological experiments – recording the firing of individual neurones in the bee’s brain – have identified that these events occur in a region called the central complex (CX).

Two types of neurones are involved; the first is a set of polarised-light-based compass neurones and the second are optic-flow-based speed neurones. The former use celestial cues to create a visual compass. The latter provide a visual odometer (Stone et al., 2017).

Together – and there are additional integrator cells that link these functions – this relatively simple 5 neuronal circuitry allows path integration, enabling the bee to return ‘home’ directly after a convoluted outward flight.

Many of these studies were conducted on the nocturnal sweat bee Megalopta genalis. This forages at night when polarised skylight provides the directional cues in its rainforest habitat.

Importantly, similar neuronal organisation is found in the CX’s of locusts, some butterflies and dung beetles. The visual odometer neurones were analysed in Megalopta genalis, but are physically and likely functionally similar to structures found in Bombus terrestris (a bumble bee).

You may have noticed that none of these studies used our favourite, Apis mellifera, the honey bee.

The evolution of termites, ants, wasps and bees

Nevertheless, there’s every reason to think that honey bee path integration involves very similar neuronal activity. Megalopta (belonging to the family Halictidae) and Bombus (a member of the Apidae family) are very distantly related and evolved from a common ancestor over 100 million years ago (Cardinal and Danforth, 2011). It’s therefore likely that all bees derived from this common ancestor – including honey bees – share similar neuronal activity underpinning their path integration ability.

Food vectors

Before considering another point about honey bee flight I wanted to to briefly mention features of the outbound trip back to the high quality food source (the red dotted line in diagram above). This is termed the food vector and is essentially the reverse of the path integrated return flight back to the colony i.e. the same length, but pointing in the opposite direction.

The waggle dance communicates this food vector to nest mates of the successful returning forager.

But what happens if bees are displaced when starting, or while following this food vector?

For example, if a huge gust of wind blew them off course by tens or hundreds of metres, or an evil eager scientist captured them as they left the hive and transported them in a dark box across a couple of fields and then released them?

Where do displaced foragers go?

Do the bees fly a corrected route to the food source (the blue dotted arrow), or do they continue flying the same vector (angle and distance – the green dotted arrow) they would have done when they left the hive?

I’m not sure this exact experiment has been done with bees (but see below), but it has been done with ants (Cataglyphis fortis). In these studies the ’displaced’ ants did alter their direction of travel (Collett et al., 1999). The food vector is more than just an angle and distance, it also points to a position relative to the nest. The redirection exhibited by the ants was not perfect, but it clearly showed they were able to integrate the path to a location other than the nest after displacement.

Gusts of wind are not the same as eager scientists

However, back to the bees.

The gust of wind and eager scientist are not equivalent. Bees cope with gusts of wind every day. It always amazes me how well bees cope on windy days.

When blown off course they will get lots of visual cues – not least changes in optic flow and their angle to the sun – both of which should be readily corrected. If they didn’t then foragers would be lost in droves on windy days … or fail to find the food source.

In contrast, the eager scientist took care to place the bees in a darkened box, thereby immediately removing visual cues such as the angle of the sun and the optic flow.

In the studies conducted with the ants the scientists made sure the ants could see the sky but not the surrounding landscape (they trained them in open topped channels). This is because ants can also use landmarks in the surrounding landscape for orientation 6.

And bees can do the same, which is the final sub-topic for this post on bee flight and orientation.

The map-like spatial memory of bees

Path integration is both useful and necessary. It means that foragers can return – fully laden – with minimum delay to the hive. They can therefore tell other foragers (via waggle dancing) promptly, and – in the case of elite foragers – they can set off again on another trip.

By reducing the distance flown – by integrating the path – they save not only time but ‘fuel’ as well i.e. path integration allows bees to maximise the nectar returned at the end of the foraging trip.

But, if all flights were a combination of random searches and path-integrated returns, why do bees go on orientation flights?

Orientation flights are short range (10’s to 100’s of metres) flights around the hive. These are taken by workers around 3 weeks after emergence as they transition form hive bees to foragers. They are also taken by older foragers if the hive is moved.

The very existence of orientation flights is compelling evidence that honey bees also use learned environmental landmarks for route finding, or at least for mapping the area around the hive to aid efficient return trips.

What evidence is there that these landmarks are used for this purpose?

Harmonic radar tracking of displaced foragers

I’ve previously discussed the use of short range harmonic radar to track bees ‘tagged’ with a small transponder. The key point is that it allows relatively accurate mapping of the entire flight of a bee up to 900 metres away. The resolution is, at best, about 3 metres.

Menzel and colleagues (Menzel et al., 2004) tracked the flights of three types of ‘displaced’ foragers:

  • SF-bees trained to a stationary feeder a few hundred metres from the hive; these have ‘route memory’ and have traversed the route from the hive to the feeder multiple times
  • VF-bees trained to a regularly moved feeder within 10 metres of the hive; these bees have no route memory
  • R-bees which were recruited by a waggle dancing forager and have only secondhand route information of the position of the feeder i.e. they have never made the trip themselves

These are not trivial experiments. To ensure the environment was as uniform as possible they conducted the experiments in a large, flat mown field approximately 800 metres square. There was no forage within the field other than the experimental feeders. The field was surrounded on all sides by uniform coniferous woodland with insufficient variation in elevation (<1.5°) above the horizontal to provide any visual clues to the bees.

The field itself was not uniform. There were differences due to different mowing times and soil conditions. In addition, the scientists erected a number of radar-transparent coloured tents around the hive to provide additional landmarks.

Common features of flight paths determined by harmonic radar studies

Bees were allowed to orientate to the new hive position and then SF- and VF-bees were collected at a feeder and R-bees were captured as they left the observation hive (having ‘watched’ a waggle dance). The bees were fitted with a transponder, released some distance away from the feeder or the hive and then tracked by radar.

SF- and VF-bees were stuffed full of syrup and so – although they could fly for a long time – were motivated to return to the hive to unload their cargo. R-bees, whilst ‘primed’ to seek the feeder, had limited range and so would have to return to the hive to refuel.

Return flights of SF-, VF- and R-bees show some common features.

The SF- and R-bees exhibited three broadly conserved flight patterns during their return trip to the hive:

  1. A fast (20 m/s) straight line flight in the direction they would have taken back to the hive (for the SF-bees) or out to the feeder (for the R-bees). The length of this part of the flight was approximately the distance between the hive and the feeder.
  2. A slow (13 m/s) curved search flight.
  3. A fast homing flight back to the hive.

The VF-bees only exhibited the slow curved search flight and the final fast homing flight. This was unsurprising as they had never learned (or been told) to follow the route between the hive and distant feeder.

Food vectors and von Frisch

We therefore have the answer to the question I posed earlier (in the Food vector section above). A bee displaced when about to embark for the first time on a trip to a distant feeder – learnt from following a waggle dance – initially flies at the angle and to the approximate distance they would have taken from the hive (stage 1 of the flight).

Remember, unlike the ants, these foragers are ‘in the dark’ while being displaced, so have no visual clues about the displacement.

This is a really nice result and supports the contention made by von Frisch that the waggle dance communicates only distance and direction (relative to the sun) information, rather than positional information (von Frisch, 1967) 7.

Homeward bound

After a period of slow curved flights the returning forager switches to a direct, fast homing flight. These started at positions – starred in the figure above – from which the bee could not see the hive (based upon distance and the known resolution of honey bee vision).

Homing flights of displaced SF-, VF- and R-bees (A, B, C respectively). H indicates the position of the hive.

Individual bees were randomly displaced around the study field. The homing flights were in a straight(ish) line and bees approached the hive from a range of different points of the compass. This argues strongly against the bees following a particular feature on the ground that led them back to the hive.

Instead, the authors argue that, since all the bees exhibit these direct homing flights, it must be based upon previous exploratory memory i.e. from orientation flights.

The tents were not critical landmarks. If they were moved some distance away the bees still returned using the same three flight phases (in the case of SF- and R-bees) and with similar navigational performance. Clearly there was sufficient information in the ground structure alone (mowing patterns, soil differences) acquired during the orientation flights.

In support of this, some of the harmonic radar data showed bees flying along boundaries between mown areas (in a similar way to homing pigeons follow rivers or motorways; Guilford and Biro, 2014.).

These experiments indicate that during orientation flights the bee develops a local spatial memory of landmarks that provide a ‘memory map’. This enables the bee to return to the nest once it recognises some of these familiar landmarks.

Repeated displacement flights of the same bee further indicated that the landmarks recognised (whatever they were) could be approached from different angles.

Final inspections

My bees are still out foraging despite the large blocks of fondant most hives are now topped with. I’m not sure what they’re collecting but it’s clearly worth the trip … and going to the initial trouble of finding it and telling other foragers about it.

Returning foragers

We usually take the amazing navigational abilities of our bees for granted. Those returning foragers are using navigational skills that evolved at least 100 million years ago while dinosaurs roamed the earth.

100 million years is a long time to develop a range of skills and subtleties; it’s no wonder we still only partially understand honey bee navigation. Of course, we don’t have to understand it to still marvel at their ability to find the way back.

And it’s worth also remembering that these navigation skills – many of which are based upon the angle of travel relative to the direction of the sun – also operate on dull, overcast days. But that’s a topic for another post …


References

  • Cardinal, S. and Danforth, B.N. (2011) ‘The Antiquity and Evolutionary History of Social Behavior in Bees’, PLOS ONE, 6(6), p. e21086. Available at: https://doi.org/10.1371/journal.pone.0021086.
  • Collett, M., Collett, T.S. and Wehner, R. (1999) ‘Calibration of vector navigation in desert ants’, Current Biology, 9(18), pp. 1031–1034. Available at: https://doi.org/10.1016/S0960-9822(99)80451-5.
  • Guilford, T. and Biro, D. (2014) ‘Route following and the pigeon’s familiar area map’, Journal of Experimental Biology, 217(2), pp. 169–179. Available at: https://doi.org/10.1242/jeb.092908.
  • Menzel, R. et al. (2005) ‘Honey bees navigate according to a map-like spatial memory’, Proceedings of the National Academy of Sciences, 102(8), pp. 3040–3045. Available at: https://doi.org/10.1073/pnas.0408550102.
  • Stone, T. et al. (2017) ‘An Anatomically Constrained Model for Path Integration in the Bee Brain’, Current Biology, 27(20), pp. 3069-3085.e11. Available at: https://doi.org/10.1016/j.cub.2017.08.052.

Tim Toady

Synopsis : The large number of beekeeping methods is both a benefit and – for beginners particularly – a distraction. Learn methods well enough to be confident when you apply them. Understand why they work and their pros and cons.

Introduction

In an earlier life as a junior academic I was generously given a crushingly boring administrative task. The details don’t matter 1 but it essentially involved populating a huge three-dimensional matrix. The matrix had to be re-populated annually … and, when I was allocated the task, manually.

To cut a long story short I taught myself some simple web-database computer programming. This automated the data collection and entry and saved me many weeks of tedious work.

Geek alert …

This minor victory resulted in me:

  • writing lots more code for my admin and research, and for my hobbies including beekeeping and photography. It’s been a really useful skill … and a lot of fun.
  • inevitably being given an additional mundane task to fill the time I had ‘saved’ 🙁 2.

The programming language I used was perl. This is a simple scripting language, which although now superseded in popularity by things like python, remains very widely used. All proper computers 3 still have perl installed.

Perl is perfect for manipulating text-based records. The name is an acronym for ’practical extraction and reporting language’ … or perhaps ’pathetically eclectic rubbish lister’, the latter reflecting its use to manipulate text (‘garbage in, garbage out’ … ) 4.

Perl was (and remains) powerful because it’s a very flexible language. You can achieve the same goal in many different ways.

This flexibility is reflected in the perl motto: ’There’s more than one way to do it’, which is abbreviated to TMTOWTDI.

TMTOWTDI is a mouthful of alphabet spaghetti, so for convenience is pronounced Tim Toady … the title of today’s post.

Why?

Because exactly the same acronym could be applied to lots of things in beekeeping.

Ask three beekeepers, get five answers

But one of the five is wrong because it involves ’brood and a half’.

Anyone who has attended an association meeting and naively asked a simple question will understand the title of this section.

’How do I … [insert routine beekeeping problem here] … ?’

The old and the wise, or perhaps the old or the wise, will recommend a series of solutions. Some will offer more than one.

Each will be different.

Many recommendations will be perfectly workable.

A few might be impractical.

At least one will be just plain wrong.

How do I avoid brace comb?

Confusingly … despite all being proffered solutions to the one question you asked, many will appear contradictory.

Do you move the queen away (the nucleus method) or leave the queen on the same site (Pagden’s artificial swarm) for swarm control? How can they both work if you do such very different things?

Ask twelve beekeepers, get nineteen answers (ONE IN ALL CAPS)

Internet discussion forums (fora?) are exactly the same, but may be less polite. This is due to the absence of the calming influence of tea and homemade cake. At least one answer will include a snippy suggestion to ’use the search facility first’.

Another will be VERY VERY SHOUTY … the respondent either disagrees vehemently or has misplaced the CAPS LOCK key.

Actually, in many ways internet discussion forums are a lot worse … though not for the reasons you might expect.

It’s not because they’re populated with a lot of cantankerous ageing beekeepers and arriviste know-it-alls.

They’re not 5.

There are some hugely experienced and helpful beekeepers online, though they probably don’t answer first or most forcefully.

The internet is worse because the audience is bigger and is spread over a wider geographic area. This is a problem as beekeeping is effectively a local activity.

If you ask at a local association meeting there will be a smaller ‘audience’ and they should at least all have some experience of the particular conditions in your area.

Včelařské fórum … and something you won’t see on the BKF … a whole sub-forum on subsidies

But if you ask on Beesource, Včelařské fórum or the Beekeeping & Apiculture forum the answers may literally be from anywhere 6. The advice you receive, whilst possibly valid, is likely to be most relevant where the responder lives … unless you’re lucky.

On one of the forums I irregularly frequent many contributors have their latitude and longitude coordinates (and sometimes plant hardiness zones) embedded in their .sig.

Geeky perhaps, but eminently sensible … 7

Tim Toady beekeeping

Let’s consider a few of examples of Tim Toady beekeeping. I could have chosen almost any aspect of our hobby here, but I’ll stick with three that are all related to the position or fate of the queen.

Queen introduction

Perhaps this was a bad option to choose first. Queen introduction isn’t only about how you physically get the new queen safely into the hive e.g. in some form of temporary cage. It’s also about the state of the hive.

Is it queenless? How long has it been queenless and/or is there emerging brood present? Is the brood from the previous queen or from laying workers? Is it a full hive or a nuc … or mini-nuc?

Successful introduction ...

Successful introduction …

And it’s about the state of the new queen.

Is she mated and laying, or is she a virgin? Perhaps she’s still in the queen cell? Is the queen the same (or a similar) strain to the hive being requeened? Is she in a cage of some sort? Are there attendants in the cage with her?

And all that’s before you consider whether it’s ‘better’ to use a push-in cage, a JzBz (or similar) cage or to omit the cage and just rely upon billowing clouds of acrid smelling smoke.

Uniting colonies

This blog is nothing if not ’bleeding-edge’ topical … now is the time to consider uniting understrength colonies, or those headed by very aged queens that may fail overwinter.

Uniting two weak colonies will not make a strong colony. However, uniting a strong with a weak colony will strengthen the former and possibly save the latter from potential winter loss (after you’ve paid for and applied the miticides and winter feed … D’oh!). You can always split off a nuc again in the spring.

All the above assumes that both colonies are healthy.

There are fewer ways of uniting colonies than queen introduction, and far fewer than the plethora of swarm control methods.

This is perhaps unsurprising as there are fewer component parts … hive A and hive B, with the eventual product being A/B.

Or perhaps B/A?

United we stand …

But which queen do you keep? 8

And does the queenright hive go on top or underneath?

And how do you prevent the bees from fighting, but instead allow them to mingle gently?

Or do you simply spray them with a few squirts of Sea breeze air freshener, slap the boxes together and be done with it?

Swarm control

If you find queen cells in your colony – assuming they haven’t swarmed already – then you need to take action or the colony will possibly/probably/almost certainly/indubitably 9 swarm.

The primary goals of swarm control are to retain the workforce – the foragers – and the queen.

There are a lot of swarm control methods. Many of the effective ones involve the separation of the queen and hive bees (those yet to go on orientation flights) from the foragers and brood. Some of these methods use unique equipment and most require additional boxes or split boards.

Split board

Split board …

But there are other ways to achieve the same overall goals, for example the Demaree method which keeps the entire workforce together by using a queen excluder and some well-timed colony manipulations.

No landing boards here ...

confused.com

And then there are the 214 individual door opening/closing operations over a 3 week period (assuming the moon is at or near perigee) needed when you use a Snelgrove board 10.

Like any recommendation to use brood and a half … my advice is ‘just say no’.

Just because Tim Toady

… doesn’t mean you have to actually do things a different way each time.

The problem with asking a group – like your local association or the interwebs – a question is that you will get multiple answers. These can be contradictory, and hence confusing to the tyro beekeeper.

Far better to ask one person whose opinion you respect and trust.

Like your mentor.

You still may get multiple answers 😉 … but you will get fewer answers and they should be accompanied with additional justification or explanation of the pros and cons of the various solutions suggested.

This really helps understand which solution to apply.

Irrespective of the number of answers you receive I think some of the most important skills in beekeeping involve:

  • understanding why a particular solution should work. This requires an understanding of the nitty gritty of the process. What are you trying to achieve by turning a hive 180° one week after a vertical split? Why should Apivar strips be repositioned half way through the treatment period?
  • choosing one solution and get really good at using it. Understand the limitations of the method you’ve chosen. When does it work well? When is it unsuitable? What are the drawbacks?

This might will take some time.

More hives, less time

If you’ve only got one colony you’ll probably only get one chance per year to apply – and eventually master – a swarm control method.

With more colonies it is much easier to quickly acquire this practical understanding.

Lots of learning opportunities here

Then, once you have mastered a particular approach you can decide whether the limitations outweigh the advantages and consider alternatives if needed.

This should be an informed evolution of your beekeeping methods.

What you should not do is use a different method every year as – unless you have a lot of colonies – you never get sufficient experience to understand its foibles and the wrinkles needed to ensure the method works.

Informed evolution

If you consider the three beekeeping techniques I mentioned earlier – queen introduction, uniting colonies and swarm control – my chosen approach to two of them is broadly similar to when I started.

However, as indicated above, there are still lots of subtle variations that could be applied.

With both queen introduction and uniting colonies I’ve more or less standardised on one particular way of doing each of them. By standardising there’s less room for error … at least, that’s the theory. I now what I’m doing and I know what to expect.

In contrast, I’ve used a range of swarm control methods over the years. After a guesstimated 250+ ‘hive years’ I now almost exclusively 11 use one method that I’ve found to be extremely reliable and fits with the equipment and time I have available.

It’s not perfect but – like the methods I use for queen introduction and uniting colonies – it is absolutely dependable.

I think that’s the goal of learning one method well and only abandoning it when it’s clear there are better ways of achieving your goal. By using a method you understand and consider is absolutely dependable you will have confidence that it will work.

You also know when it will work by, and so can meaningfully plan what happens next in the season.

So, what are the variants of the methods I find absolutely dependable?

Queen introduction

99% of my adult queens – whether virgin or mated – are introduced in JzBz cages. I hang the queen (only, no attendants) in a capped JzBz cage in the hive for 24 hours and then check to see if the queenless (!) colony is acting aggressively to her.

If they are not I remove the cap and plug the neck of the cage with fondant. The bees soon eat through this and release the queen.

Checking for aggression

I used to add fondant when initially caging the queen but have had one or two queens get gummed up in the stuff (which absorbs moisture from the hive). I now prefer to add it after removing the cap. The queen needs somewhere ‘unreachable’ in the cage to hide if the colony are aggressive to her.

It’s very rare I use an alternative to this method. If I do it’s to use a Nicot pin on cage where I trap the queen over a frame of emerging brood 12.

Nicot queen introduction cages

I use this method for real problem colonies … ones that have killed a queen introduced using the JzBz cage or that may contain laying workers.

Doing the latter is a pretty futile exercise at the best of times 🙁 .

Uniting colonies

Almost all colonies are united over newspaper. A sheet to two of an unstapled newspaper is easy to carry and uniting like this is almost always successful.

The brood box being moved goes on top. I want bees from the moved box to realise things have changed as they work their way down to the hive entrance. That way they’re more likely to not get lost when returning.

An Abelo/Swienty hybrid hive ...

An Abelo/cedar hybrid hive … uniting colonies in midsummer

I don’t care whether the queen is in the upper or lower box and, if there’s any doubt that one of the colonies isn’t queenless, I use a queen excluder over the newspaper. I then check the boxes one week later for eggs.

I’m not absolutely certain one of the colonies is queenless

At times I’ve used a can of air freshener and no newspaper. This has worked well, but it’s one more bulky thing to carry. I also prefer not to expose my bees to the chemical cocktail masquerading as Sea breeze, Summer meadow or Stale socks.

Since uniting doesn’t necessitate a timed return visit there’s little to be gained from seeking alternatives to newspaper in my view. Perhaps if I lived in a really windy location I’d have a different opinion … placing the newspaper over the brood box can be problematic in anything more than a moderate breeze 13.

Swarm control

Like many (most?) beekeepers I started off using the classic Pagden’s artificial swarm. However, I quickly ran out of equipment as my colony numbers increased – you need two of everything including space on suitably located hive stands.

I switched to vertical splits. These are in essence a vertical Pagden’s artificial swarm, but require only one roof and stand. If you plan to merge the colonies again i.e. you don’t want to ’make increase’, vertical splits are very convenient. However, they can involve a lot of lifting if there are supers on the colony.

Vertical split

Vertical split – day 7 …

Now I almost exclusively use the nucleus method of swarm control. Used reactively (i.e. after queen cells are seen) it’s almost totally foolproof. Used proactively (i.e. before queen cells are produced) also works well. In both cases the timing of a return visit to reduce queen cells is important, and you need to use good judgement in deciding how strong to make the nuc.

Here's one I prepared earlier

Here’s one I prepared earlier

The nucleus method has a couple of disadvantages for my beekeeping. However, its ease of application and success rate more than make up for these shortfalls.

Tim Toady is ‘a good thing’

I love the flexibility of perl for programming. I can write one-liners to do a quick and dirty file conversion. Alternatively I can craft hundreds of lines of well-documented code that is readable, easy to maintain and robust.

Others, in the very best tradition of Tim Toady, might write programs to do exactly the same things but in a completely different way.

The flexibility to tackle a task – the three used above for example, or miticide treatment, queen rearing, uncapping frames or any of the hundreds of individual tasks involved in beekeeping – in different ways provides opportunities to choose an approach that fits with your diary, manual dexterity, available equipment, preferences, ethics or environment.

In this regard it’s ‘a good thing’.

Choice and flexibility are beneficial. They make things interesting and, for the observant beekeeper, they provide ample new opportunities for learning.

… and a distraction

However, this flexibility can also be a distraction, particularly for beginners.

That is why I emphasised the need to learn the intricacies of the method you choose by understanding the underlying mechanism, and the subtleties needed to get it to work absolutely dependably.

Don’t just try something once and then do something totally different the next year 14. Use the method for several years running (assuming it’s an annual event in the beekeeping calendar), or at least on a lot of different colonies.

Choose a widely used and well-documented method in the first place 15. Read about it, understand it and apply it. Tweak it until it either works exactly as you want it to i.e. reliably, efficiently, quickly or whatever, or choose a different widely used and well-documented method and start over again.

Get really competent at the methods you choose.

Once your beekeeping is built upon a range of absolutely dependable methods you have the foundations to be a little bit more expansive.

You can then indulge yourself.

Explore the options offered by Tim Toady.

Things might fail, but you always have a fallback that you know works.


Note

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