That is the prequel to Larger queens, higher queens – half 1 which was all concerning the maternal impact in honey bees.

The maternal impact, though well-known in different species, has solely just lately been demonstrated in honey bees. Primarily, it entails the queen preferentially laying bigger eggs in queen cells than she lays in employee cells. These bigger eggs become bigger and heavier queens.

Maybe unsurprisingly – although additionally reassuringly – these bigger queens have extra ovarioles and lay extra eggs than smaller queens. Lastly, these bigger queens seem to move on fascinating traits to their progeny; second era queens are additionally bigger, as are the employees.

Half 1 on this sequence of three (or maybe now 4) posts described the demonstration of the maternal impact. On this publish I’ll discover – inevitably briefly as a result of availability of a few of the historic literature – why bigger queens could be higher.

It is vital to stress that none of the sources used for this publish had been conscious of the maternal impact in honey bees. Though there could have been hints such a factor occurred in research relationship again to the 1970’s, the proof was circumstantial or – at greatest – correlative, and it wasn’t demonstrated till 2019.

Components affecting the worth of a queen

This heading is lifted verbatim from Laidlaw and Eckert’s Rearing queens (1962). Regardless of now being over 60 years previous, the vast majority of this ebook – a minimum of by way of the sensible beekeeping – stays related. Unsurprisingly, there isn’t any point out of Varroa which wasn’t recognized within the USA till 1987 {{1}}.

The worth of a queen relies upon, largely, upon her skill to put a ample variety of eggs to keep up a powerful colony applicable to the varied seasons of the yr (Laidlaw & Eckert, 1962).

The egg-laying skill of the queen is the main measure of her worth. It ought to be apparent why that is; a queen that lays too few eggs, or too many unfertilised eggs, or who doesn’t begin laying early sufficient within the season, or who stops laying too quickly within the autumn, will end in an undersized colony that’s too small to thrive.

Gradual spring enlargement signifies that the colony is unlikely to be large enough to swarm (reproduce).

As a beekeeper you would possibly suppose that is “a very good factor” … it is not.

An undersized colony will gather much less nectar, shall be much less capable of defend itself towards robbing, and should not gather ample shops to outlive the winter. Winter survival can be compromised by too few winter bees … quite a few research have proven that enormous colonies (in late autumn, not essentially in midsummer) have higher overwinter survival.

High quality and amount

Laidlaw and Eckert certified their definition of the worth of a queen by additionally commenting on how she is chargeable for the traits of the colony.

A queen that laid ‘ample variety of eggs to keep up a powerful colony’ is of little worth if the colony is aggressive, vulnerable to illness, or that swarms as quickly as your again is turned {{2}}.

Nonetheless, these qualities are largely inherited and/or decided by environmental situations.

When you enable an aggressive colony to requeen itself, don’t be stunned if the colony stays aggressive as soon as the employee inhabitants is changed with the brand new queen’s brood. On this case, the aggressive trait is inherited.

Equally, if it is raining, or almost midnight (or, for spectacular impact, each), and also you elevate the roof and crownboard, even a usually placid colony will react defensively. That is the affect of the atmosphere. Precisely the identical issues applies in a nectar dearth, or if the colony is queenless.

Though it would possibly be preferable to be confronted with a smaller variety of psychotic bees at midnight on a wet night time, the truth is that the qualitative traits – by way of colony survival and productiveness – are usually secondary to the manufacturing of ample eggs to keep up a powerful colony.

Reproductive potential

The reproductive potential of the queen contains, however isn’t restricted to, her egg laying. Reproductive potential is outlined by way of:

• fecundity – the quantity or price at which eggs are laid
• fertility – (associated to above) however maybe higher outlined because the quantity or proportion of fertilised eggs produced
• longevity – the interval over which the queen is productive, outlined each by way of years, however (for my part) extra importantly, by way of the months of productiveness per season {{3}}

Not all queens are the identical measurement. My native darkish bees have comparatively small queens, whereas my bait hives generally entice swarms headed by monumental yellow queens. That is the pure variation between completely different strains – and hybrids of these strains – of honey bees.

Extra related to reproductive potential is the demonstration that queens of completely different sizes might be produced from a single pressure of bees.

This has been exploited to check the reproductive potential of honey bees. These scientific research largely post-date the final acceptance that ‘greater queens are higher queens’, however present tangible proof supporting this view.

All that potential

The destiny of a fertilised egg relies upon totally upon its atmosphere. That is termed polyphenism – a mix of poly- (multiple) and phenotype (the observable traits of a person) – which implies:

The capability of a genotype to supply two or extra distinct phenotypes in response to an environmental issue similar to temperature, photoperiod, or diet.

In honey bees, it’s diet that determines the destiny of the egg.

If the egg is laid in a horizontal cell – a employee cell – it’s fed employee jelly and, after pupation, emerges as a feminine employee (the blue line within the cartoon under).

In distinction, if the cell orientation is vertical, the nurse bees feed the growing larvae on a wealthy food regimen of royal jelly (the purple strains). This induces an in depth vary of DNA modifications (methylation) which end in adjustments within the expression of a variety of genes. After pupation, a queen emerges.

It’s (predominantly, however not solely) the further sugar within the royal jelly that results in queen growth

Fortuitously for clumsy newbie beekeepers and people of us who rear queens {{4}} (and for the honey bee colony) there’s a little bit of flexibility in the course of the first 0 to three days of larval growth that permits older larvae to even be reared into queens, underneath sure circumstances.

If a younger larva is transferred from a horizontal employee cell to a vertically-oriented queen cell, will probably be fed royal jelly and reared as a queen. Equally, if the queen is misplaced, the bees will re-engineer a employee cell to be vertically oriented, feed the larva it incorporates royal jelly, and thereby produce the queen.

It is this ‘magic’ that permits us to rear queens and that allows the colony to often get well from the – in any other case catastrophic – lack of a queen attributable to cackhanded beekeeping or illness.

After 3 days of larval growth, this skill to reprogramme a employee right into a queen is misplaced.

Operate not kind

Nonetheless, there’s a direct relationship between the quantity of royal jelly fed to a growing larva, and the way queen-like the ensuing grownup bee is.

The longer a larva is fed royal jelly, and subsequently the extra she consumes, the extra queen-like the grownup shall be (indicated by the thickness of the purple strains).

Growing queen larvae are in a perpetual ‘all you may eat’ restaurant, whereas growing staff ‘get pleasure from’ much less of a much less wealthy food regimen.

In actuality, it is a bit extra sophisticated than that, however at a primary approximation that’ll do.

Seminal research carried out by Jerzy Woyke (1971) demonstrated that queens raised from employee larvae of accelerating age had diminished reproductive potential; outlined by way of their weight, ovariole quantity, spermatheca diameter, and saved sperm counts.

That is why it is very important use very younger larvae when queen rearing. It is also why colonies preferentially select 3 day previous eggs when rearing queens underneath the emergency response.

Sadly, Woyke’s research are hidden behind the Journal of Apiculture Analysis‘s paywall and even my ‘entry all areas’ college account cannot get to a replica of the paper.

By no means thoughts … Woyke was finding out the phenotype – the bodily traits – of the queen. So far as sensible beekeeping is worried, it is what the queen does with that additional weight, these additional ovarioles and the elevated saved sperm that issues.

And, it seems, there is not essentially a direct relationship between the bodily attributes of a queen and her reproductive potential. Some subsequent research have produced contradictory outcomes; bigger or extra ovarioles do not all the time equate to extra eggs, although Nelson & Gary (1983) demonstrated a direct relationship between heavy queens, better brood space and elevated honey manufacturing.

Colony health and queen measurement

Sometimes, these kinds of research are achieved by rearing queens from younger (day 0) or previous (day 2) larvae and evaluating the efficiency of the ensuing queens, or the colonies that they head.

What different traits of a colony could possibly be measured as a method of figuring out whether or not bigger queens are fascinating?

I’ve beforehand mentioned polyandry and colony health, and the attention-grabbing idea of hyperpolyandry and larval choice:

Who’s the daddy?

I’ve just lately mentioned the significance and affect of polyandry for honey bee colonies. Briefly, polyandry – the mating of the queen with a number of (~12-18) drones – is important for colony health e.g. skill to withstand illness, forage effectively or overwinter efficiently. Hyperpolyandry, for instance ensuing from instrumental insemination of the

These posts are value (re)studying … my writing could be as poor as ever, however the underlying science is great, and the outcomes are fascinating.

Queens go on a number of mating flights and mate with a number of drones. It is vital that they do because it will increase the genetic range throughout the colony. This genetic range is important to make sure colony health; this can be a catch-all time period that describes how nicely the colony survives and reproduces.

A fitter colony will exhibit higher illness resistance, will overwinter nicely and can construct up strongly to swarm (reproduce) the next season.

So, how do ‘excessive’ and ‘low’ high quality queens – reared from younger or previous larvae respectively – evaluate when their mating success is analysed?

It takes two to tango

One research, by Tarpy et al., (2011), aimed to research the mating behaviour and success of excessive and low high quality queens, an vital purposeful high quality associated to colony health.

Tarpy measured the bodily traits of the queens (reared by grafting 0 day or 2 day previous larvae, however in any other case handled in an an identical method).

It is value mentioning right here that the ‘low high quality’ queens had been so small that many may get by the queen excluder on the hive entrances, so stopping correct recording of the whole variety of mating flights.

The low high quality queens had been considerably lighter (~87% that of top of the range queens), had a narrower thorax (~94%) and a decreased spermatheca diameter (~92%) and therefore quantity. As a consequence, the ‘low high quality’ queens saved considerably much less sperm (~65%), although the general stage of sperm viability was the identical.

Why was there much less sperm? Most likely as a result of the queens had mated with fewer drones. Each the noticed mating quantity and the efficient paternity frequency – decided by genetic evaluation of ensuing brood to quantify the distinct patrilines within the colony – had been considerably decrease within the ‘low high quality’ queens (at ~82% and ~78% respectively).

Do these variations matter?

Doubtlessly.

Though not measured on this research, colony health – as outlined above – is expounded to the genetic range of the colony. If the queen mates with fewer drones the range is inevitably decreased, which might be detrimental. Moreover, if the quantity of sperm saved is inadequate it might restrict the reproductive longevity of the queen.

Penalties for the colony

In an extension of those research, Tarpy and colleagues (Rangel et al., 2013) measured sure traits of colonies headed by ‘low high quality’ or ‘prime quality’ queens.

The queens had been reared utilizing commonplace methods after which used to requeen a bundle of bees (US readers shall be conversant in these … it is a field containing bees however no comb or brood). The ensuing packages had been hived on frames with or with out basis, in order that the bees may draw employee or drone comb based mostly upon the wants of the colony. Colonies had been monitored from Could to September, and their subsequent overwintering survival recorded. An additional 40 colonies (50/50 low or prime quality queens) had been arrange the next season to repeat the evaluation of overwintering survival.

Colonies headed by ‘prime quality’ queens (stable strains within the graphs) constructed ~34% extra employee comb (a) and ~144% extra drone comb (b) and saved extra pollen and nectar (c), all of which had been statistically important. Though there have been numerical variations in each employee and drone brood manufacturing (e and f, respectively) these weren’t statistically important. Lastly, colonies headed by ‘prime quality’ queens had been estimated to comprise ~41% extra staff (f) than these headed by ‘low high quality’ queens.

Larger queens, greater colonies 😄.

Survival of the fittest?

Nonetheless, the overwinter colony survival is, frankly, a little bit of a multitude and is confounded by the way in which it’s offered within the paper. Primarily, within the first yr most of the colonies perished, and there was no important distinction between colonies headed by ‘excessive’ or ‘low’ high quality queens.

Not good 😔.

Within the repeat of this a part of the research, 75% of the colonies headed by ‘prime quality’ queens survived overwinter, in distinction to solely 30% of the ‘low high quality’ queen colonies.

Complicated 😕. Such diametrically opposing outcomes can’t be meaningfully interpreted.

I believe this a part of the research must be repeated.

One attention-grabbing remark was the variety of instances that queens had been outdated.

My expectation would have been that the colonies headed by ‘low high quality’ queens would have been outdated rather more often. This is able to match with earlier observations on the supersedure of poorly mated queens, or these failing attributable to illness. Nonetheless, though supersedure was noticed, there was no important distinction within the numbers of ‘excessive’ or ‘low’ high quality queens that had been changed.

Relevance to sensible beekeeping

All beekeepers rear queens. Not all know they rear queens, however the truth that queens have a finite lifespan and the beekeeper proceed to preserve bees signifies that queens have to be being reared {{5}}.

When you rear queens passively, by which I imply merely letting colonies requeen throughout swarm management, or by splitting colonies, then it is value remembering that the bees will preferentially select 3 day previous eggs and that the ensuing queens must be well-fed throughout their early growth.

If there’s a dearth of nectar or a scarcity of pollen, feed the colony. Belief the alternatives the bees make by way of the larvae they rear as queens. They know what they’re doing.

Nonetheless, if the colony has little or no eggs or very younger larvae then present some … they’ll solely work with what they’ve within the hive and if, for no matter motive, the one larvae are 2-3 (or extra) days previous they are going to solely be capable to rear small, low high quality, queens.

Lively queen rearing

When you rear queens actively i.e. by making ready a cell elevating colony, including larvae after which transferring the ensuing queens (or cells) to mating nucs, then it is not value going to all that palaver except you may make sure that; a) the larvae are as younger as attainable, and b) the cell elevating colony is full of younger bees and has ample nectar and pollen.

I exploit the Ben Harden queenright queen rearing technique. This entails establishing a four-frame ‘chimney’ above a busy brood field. One of many frames incorporates the larvae – often grafted, although they do not need to be – one is filled with open brood, to attract up nurse bees from the brood field, and the remaining two are pollen-filled. And subsequent to that may be a frame-feeder to which I add syrup each day till the cells are sealed.

All kinds of different methods have been used to try to assure good larval diet. Laidlaw and Eckert (1962) and David Woodward (in his ebook Queen Bee: Biology, Rearing and Breeding (2010), Northern Bee Books) each describe ‘double grafting’. This technique is designed to make sure the larvae are nicely fed from the second they’re transferred to the cell elevating colony, even perhaps earlier than they get the eye of the nurse bees.

Larvae are grafted into cell cups and added to the cell elevating colony for 2 days. Throughout this era they’re fed copious quantities of royal jelly. After two days, these preliminary larvae are eliminated (however the royal jelly isn’t) and changed with one other very younger larva.

While I perceive the logic, this is not a technique I exploit. Laidlaw and Eckert indicate that larval feeding earlier than grafting might be extra vital than within the fast interval after grafting earlier than the nurse bees get busy.

Choosing winners, half 2

Some larvae are nutritionally disadvantaged and should produce suboptimal queens. Grafting could miss the perfect larvae the colony would choose for rearing as emergency queens.

Current research on larval alternative by staff means that the bees additionally think about well-fed larvae are the perfect beginning materials for brand spanking new queens … the colony from which larvae are sourced also needs to be nicely fed if wanted.

Notes

Half 2 on this poorly sorted sequence will comply with subsequent month as soon as just a few ultimate experiments have been carried out. I believe it is nearly sure that I’ll want a ultimate publish (half 3?, I’ve misplaced rely) to debate a few of the gaps in our understanding of the maternal impact.

References

Nelson, D.L., and Gary, N.E. (1983) Honey Productiveness of Honeybee Colonies in Relation to Physique Weight, Attractiveness and Fecundity of the Queen. Journal of Apicultural Analysis 22: 209–213 https://doi.org/10.1080/00218839.1983.11100589.

Rangel, J., Keller, J.J., and Tarpy, D.R. (2013) The results of honey bee (Apis mellifera L.) queen reproductive potential on colony development. Insect Soc 60: 65–73 https://doi.org/10.1007/s00040-012-0267-1.

Tarpy, D.R., Keller, J.J., Caren, J.R., and Delaney, D.A. (2011) Experimentally induced variation within the bodily reproductive potential and mating success in honey bee queens. Insect Soc 58: 569–574 https://doi.org/10.1007/s00040-011-0180-z.

Woyke, J. (1971) Correlations Between the Age at Which Honeybee Brood was Grafted, Traits of the Resultant Queens, and Outcomes of Insemination. Journal of Apicultural Analysis https://www.tandfonline.com/doi/abs/10.1080/00218839.1971.11099669.

{{1}}: Although it was undoubtedly there earlier than then because it was present in a minimum of 12 states that autumn.

{{2}}: That is not a scientific definition, however one which applies all too often 😉 .

{{3}}: A 7 yr previous queen that solely laid eggs in Could and June is of little use to anybody.

{{4}}: I belong to each teams.

{{5}}: OK, sure they may be shopping for them in from Greece each season, however they’d be nuts to do this, would not they?