Swarming is the colony’s natural mode of reproduction. For the beekeeper it can reduce yield and divide colonies in an uncontrolled way — but it can also be used for targeted multiplication, the formation of vigorous nucleus colonies and the exploitation of a brood break. This practical article translates the biological knowledge of the ApiSavoir reference article on swarming into concrete decisions at the apiary.

1. Placing swarming in context

In swarming it is not the queen alone that reproduces, but the colony as a social unit. The prime swarm leaves the hive with the mated old queen and a large part of the adult workers. The mother colony, by contrast, retains the combs, brood, food stores and part of the workers, but must restore its reproductive function through a young queen. It may also continue the division temporarily by issuing one or more cast swarms.

The division is more asymmetric than the common notion of “roughly half the colony” suggests. In a direct measurement of natural colony divisions, roughly three quarters of the adult workers left on average with the prime swarm, although the proportion varied among colonies (Rangel & Seeley, 2012). In practical terms, after departure the swarm has a large mobile workforce but no combs and no brood; the mother colony retains the infrastructure but depends on the development and successful mating of a new queen.

Seasonal development of brood and Varroa: the actual dynamics depend strongly on site, year, nectar flow, colony strength and management system.

Population development in spring is therefore central to the swarming period. No single figure determines the outcome: brood quantity, emergence waves, the number of adult bees, food availability, use of space, the queen, weather and genetics must be considered together. European comparisons show that both genotype and site influence swarming behaviour; environmental conditions can strongly affect how genetic swarming propensity is expressed (Uzunov et al., 2014).

The beekeeper influences colony development and swarming dynamics through the provision of space, feeding, queen management, formation of young colonies and health management.

A strong colony is therefore not “too strong”, but capable of reproducing. The practical task is not to prevent strength as such, but to decide whether that strength should be directed towards the honey harvest, the formation of young colonies or natural colony division.

2. Recognising swarm preparation: a process, not a single trigger

Preparation does not begin with the first visible queen cell. Demographic, social and physiological changes precede the stage at which queen rearing becomes obvious. There is no universal “day zero” or fixed total duration of swarm preparation.

Nor has research identified a single trigger valid in all colonies. It is particularly well supported that a high density of adult bees can increase the propensity to swarm. Experimentally restricting only the area available for egg laying, by contrast, did not produce the same effect (Simpson & Riedel, 1963; Simpson & Greenwood, 1975). “The queen has no more room to lay” is therefore too simple an explanation when used on its own.

A great deal of capped brood, relatively little open brood and a very densely occupied brood area may, in practice, herald a strong emergence wave. This ratio is not, however, a validated threshold for swarming.

2.1 What the beekeeper can actually observe in the colony

In practice, an important configuration often consists of several characteristics occurring simultaneously:

• a very large number of adult bees in a heavily occupied area;
• large areas of capped brood close to emergence;
• relatively little open brood compared with capped brood, temporarily changing the demographic structure of the brood;
• nectar or pollen within the brood nest and fewer immediately available cells;
• changes in comb-building activity and occupation of space;
• the first swarm cells containing eggs or actively fed larvae;
• reduced egg laying or other visible changes in the activity of the old queen;
• rapid development of several of these features between two inspections.

2.2 The queen acts within a social information system

The old idea that swarming begins simply because the queen’s pheromones become “diluted” in a large colony is too mechanistic. Part of the information about queen fertility is distributed by workers that contact her and subsequently relay that information through the colony’s social network (Richardson et al., 2024).

Queen mandibular pheromone is also only one component of the system. Its inhibitory effect on queen rearing declines when it acts alone for several days, while eggs and very young larvae provide additional reproductive information (Pettis et al., 1995, 1997). Worker responses to queen pheromones also vary with factors including worker state and genotype (Pankiw et al., 1994).

The queen forms part of a social information system. A simple mechanism of the type “less footprint pheromone = queen cells” does not explain swarm preparation. Photo: S. Imboden

The practical observation that queen cells sometimes appear or disappear following spatial reorganisation therefore remains interesting. It should, however, be interpreted as a possible consequence of an overall change in the social and spatial system rather than as evidence for a single pheromonal mechanism.

2.3 Queen cells indicate a stage — not, on their own, a point of no return

An empty queen cup is only weakly informative. A cell containing an egg represents a further stage, but queen rearing may still be abandoned. A young larva being actively fed in a swarm cell, by contrast, shows that the colony is genuinely investing in queen rearing. Several capped swarm cells together with other converging signs indicate an advanced stage in practical terms.

Allen (1965) showed that queen rearing can be initiated and later abandoned and that the construction of queen cells does not necessarily lead to a swarm. A single capped cell therefore does not represent an absolute biological boundary. In a heavily occupied colony with reduced laying and several advanced swarm cells, however, the practical risk of imminent departure is clearly higher.

Swarm cells are an important warning signal. Their contents, the intensity of tending, their developmental stage and, above all, the dynamics between two inspections all need to be considered.

2.4 Poor weather can cluster swarm departures in time

The familiar observation that many swarms suddenly depart after several cold or rainy days is plausible and partly documented directly. In an analysis of 1,335 swarming events in Germany, departures were rare on rainy days and increased when warm conditions suitable for flight returned (Henneken et al., 2012). Fell et al. (1977) had already described how poor flying conditions can delay the departure of colonies already prepared to swarm.

The first warm day therefore does not necessarily “create” swarm preparation. Rather, it can allow several already prepared colonies to leave within the same weather window. During poor weather more foragers also remain in the hive, which may temporarily increase local bee density; this second pathway is biologically plausible, but has not been demonstrated as a complete causal chain triggering swarming (Riessberger & Crailsheim, 1997).

3. From the prepared colony to the prime swarm

Recognise what happens in the final days before departure and which signals mobilise a swarm that is already prepared.

In advanced swarm preparation it is not only the brood nest that changes. The old queen is progressively prepared for flight. Her body mass decreases during preparation, in temporal association with the rearing of future queens (Morse et al., 1966). Workers also alter their feeding of the queen and use mechanical or vibratory signals that can influence her behaviour and reproductive activity (Pierce et al., 2007).

The workers prepare themselves as well. Before departure, swarm bees carry more food in their crops; the available data support the existence of a collectively distributed, transportable energy reserve rather than a general, massive accumulation of additional body reserves (Combs, 1972; Leta et al., 1996). This energy is subsequently available for flight, thermoregulation and comb building.

There is no universal biological duration between the beginning of preparation and departure. Practical time estimates based on the first visible signs describe only an already advanced part of the process.

3.1 The prime swarm normally leaves with the old queen

The prime swarm leaves the colony with the mated old queen. It therefore generally departs before later cast swarms, which are accompanied by young queens, usually unmated. The older representation that emergence of the first young queen normally triggers the prime swarm is misleading: the young queens’ signals, tooting and quacking, operate mainly in regulating the phase after the prime swarm.

Young queens and their vibratory signals play a role mainly in the regulation of possible cast swarms — they are not the normal trigger of the prime swarm.

3.2 Just before departure, preparation becomes movement

A small fraction of workers may already explore potential nest sites before departure of the prime swarm (Rangel et al., 2010). This search must be distinguished from the subsequent collective decision, which is developed further by the scouts and completed mainly from the swarm cluster.

Shortly before departure, worker piping helps prepare workers for flight and synchronise their activation (Seeley & Tautz, 2001). Buzz-runs accompany the intense collective activation immediately before take-off (Rittschof & Seeley, 2008).

There is therefore no single “start button”. An already prepared state, weather conditions suitable for flight, activation signals and the spatial dynamics of the bees act together.

The departure of a prime swarm is spectacular — biologically it represents the mobile unit resulting from colony division, not the end of the process.

4. Prime swarm, nest-site choice and cast swarms

The prime swarm generally does not fly directly to its final home. It often first forms a cluster nearby. This cluster is not a passive aggregation: it keeps the bees together, regulates temperature and mechanical loads, serves as a base for the scouts and allows the collective decision over the future nest site to continue.

The swarm cluster is a temporary, functional colony without combs. Individual scouts may begin searching before departure; afterwards the search continues from the cluster.

4.1 Not the whole swarm searches

Only a minority of workers explore cavities. These scouts inspect potential nest sites, return and recruit further scouts through their dances. The search may cover a substantial area; in a recent field study, swarm dances indicated numerous alternative sites and, in some cases, distances of several kilometres (Visick et al., 2024).

The decision is not a vote in which each bee has one voice. It is better described as a combination of individual assessment, differential recruitment, gradual attrition of support for alternatives, mutual inhibition and quorum. Once enough scouts are present at a site, the colony progressively shifts from comparing options to preparing for departure. The queen does not choose the nest site.

4.2 What makes a nest site attractive?

Classic experiments revealed preferences for certain characteristics: an intermediate volume — around 40 litres in the historical experiments —, a relatively small opening, an entrance situated towards the lower part of the cavity and some elevation above the ground (Seeley & Morse, 1978). Recent studies of natural tree cavities in Central Europe also show that occupied cavities can vary substantially. The classic findings therefore do not define a universal “ideal hive” (Rutschmann & Kohl, 2026).

Odours can favour discovery of a site. Odours from old comb and Nasonov signals, among others, can increase attractiveness (Schmidt, 2001). For bait hives this means: attractiveness increases the probability of discovery; it guarantees neither the biological quality of the site nor that it will prevail over all other options.

4.3 Cast swarms continue the same colony division

In the mother colony, several young queens may reach maturity at nearly the same time. A queen already free produces tooting, while mature queens still within their cells respond with quacking. Workers can delay the emergence of individual young queens and thereby participate actively in regulating the subsequent course of events (Grooters, 1987).

When a cast swarm is issued, it is generally smaller than the prime swarm and accompanied by a young queen that is usually still unmated. This new unit therefore faces an additional bottleneck: the queen must first mate successfully before new workers can be produced.

Cast swarms are generally smaller and carry a young queen, often still unmated. Their development is therefore more demanding in temporal and demographic terms.

5. Collecting and hiving a swarm

A collected swarm is not a “residual group”, but a highly active founding unit: it has a large worker population, transportable energy reserves and — in the case of a prime swarm — an already mated queen. The origin, genetics and health status of swarms from elsewhere are, by contrast, often unknown.

Collecting a swarm at Montfavet around 1900: the principle remains the same — recover the queen and the main mass of the cluster together as far as possible.

5.1 A practical sequence

1. Settle the cluster: if necessary, mist it lightly with clean water. Sugar water to weigh down the wings is unnecessary and can leave sticky surfaces.
2. Recover the main mass: shake the cluster into a well-ventilated swarm box or nucleus box, or brush it off gently.
3. Watch the entrance: leave the box nearby in the shade with the entrance open so that bees still on the wing can rejoin the queen or the main cluster.
4. Close in the evening: move the box only once the great majority of bees has entered.
5. Hive the swarm: install it in a clean hive offering sufficient comb-building surfaces. Prime swarms can often be hived directly.
6. Assess food availability: in the absence of a nectar flow, or for a small swarm, feed as required; during a good flow, substantial routine feeding is unnecessary.
7. Use the Varroa window: as long as the swarm is genuinely broodless, this period can be used for an oxalic acid treatment against Varroa destructor, provided this is consistent with the current Swiss Varroa-control strategy and the authorised instructions for the product used. Introducing a brood frame immediately removes this advantage.
8. Follow-up inspection: check comb building, food stores and development. In a prime swarm, subsequently verify the normal resumption of brood. In a cast swarm, do not conclude too quickly that the colony is queenless: the young queen must first make her mating flights and then begin laying.

Collecting and hiving a swarm: shade, ventilation, a quiet entrance and a follow-up inspection of the new colony are essential.

5.2 Cellar confinement: a practical option, but not an obligation

Cellar confinement is used in some procedures, particularly for artificial swarms, unusually restless units or when relocation is planned. It can help a stable cluster to form. It is, however, not a biologically obligatory step for every prime swarm, and its duration is not universal.

5.3 Bait hives and swarm boxes

Many beekeepers report good experiences with bait hives. Their probability of success depends strongly on location, visibility, odour and the alternatives available at the same time.

Bait hives and swarm boxes illustrate well how practical observation and biology can converge. A site that is easy to discover and smells attractive may draw the scouts’ attention early. This does not guarantee capture, however — scouts compare several discovered options, and the decision depends on the full set of alternatives.

Old comb can increase the attractiveness of a box, but should only be used when its sanitary origin is secure. Attracting a swarm does not justify bringing potentially contaminated comb into the apiary.

The old beekeeping saying that an early swarm is more valuable than a late one has a biologically plausible basis: the earlier a new colony is founded, the more time it has to build comb, develop its population and establish winter stores. It is not suitable as a fixed calendar, however — altitude, nectar-flow patterns, climate and year can shift the available development window substantially.

6. The mother colony: risks and opportunities after swarming

After departure, assess the two resulting units separately and monitor the queen, food stores, Varroa and any cast swarms in a targeted way.

After a prime swarm, two distinct developmental trajectories must be managed. The swarm must build a new nest and produce a new generation; the mother colony must pass through the phase of young queens, resume normal laying and rebuild its population.

6.1 The mother colony needs time for its new queen

After the prime swarm, several queen cells may still be present. If the risk of cast swarms is to be reduced, beekeeping practice includes inspecting these cells and, depending on the chosen method, reducing their number. This intervention directly affects the number of young queens available to continue the division, but its outcome depends on the colony’s stage and on how the remaining cells and queens are managed.

This practice also carries a risk: if all options are reduced too early to a single, as yet unproven queen and she is lost during emergence or mating, the colony may have no remaining reserve.

Tooting and quacking indicate that young queens are in different states; they do not automatically prove that a cast swarm will leave the following day. These signals should be interpreted together with colony strength, remaining cells, season and the observed development of the colony.

The Bee Health Service currently recommends inspecting a colony that has swarmed after approximately three weeks to verify the presence of eggs or a new functional queen and to ensure an adequate food supply. If the colony is genuinely broodless at that point, this window can also be used for an oxalic acid treatment in accordance with current Swiss recommendations and the authorised use of the product.

6.2 Queenlessness test

A colony without visible brood is not automatically queenless. A young queen may still be unmated or may not yet have begun laying. If doubt remains after an appropriate interval, a bee-free frame from a healthy colony containing eggs and very young larvae can be used as a practical queenlessness test.

The construction of emergency queen cells is a strong indication that no functionally recognised queen is present. Conversely, the absence of emergency queen cells alone does not prove absolutely that a young queen is present and functional. The result must be interpreted within the colony’s timeline and, where necessary, checked again.

6.3 A swarm is generally less defensive — but not “incapable of stinging”

Swarms are often less defensive than a colony established in its nest. Individual bees can nevertheless sting if they are crushed, shaken heavily or otherwise disturbed.

A swarm possesses neither brood nor fixed food stores and does not yet defend an established nest cavity. This is why swarms are often remarkably calm. The old rule that “a bee gorged with honey does not sting” should not, however, be taken literally. Swarm bees can sting too. Calm movements, protection appropriate to the situation and avoiding crushing bees remain sensible.

6.4 Varroa: a favourable window, not a reset

Swarming distributes phoretic mites between the resulting units and creates interruptions in the brood cycle. This can temporarily slow the reproduction of Varroa destructor, but does not eliminate the mites. In apiaries where colonies stand close together, reinvasion may subsequently reduce this initial advantage (Seeley & Smith, 2015). A collected swarm should therefore not be regarded as free of Varroa.

Nor is a “health swarm” specifically triggered by heavy Varroa infestation scientifically established as a distinct category. A possible health benefit of colony division and brood interruption must be distinguished from the question of what triggers reproductive colony division.

6.5 Survival of free-living colonies varies greatly with context

Free-living colonies can survive for very different lengths of time. Varroa and viruses constitute major risks, but there is no universal rule that “without treatment every swarm dies within two years”. Photo: S. Imboden

Survival rates of free-living colonies vary substantially among regions and studies. Climate, food resources, cavity quality, genetics, Varroa, viruses and reinvasion act together. For practice, however, the conclusion remains clear: a collected swarm of unknown origin should be assessed for health and incorporated into the apiary’s Varroa-management strategy.

7. What can favour swarming?

The following list is deliberately not a list of “triggers”. It describes factors and configurations that may be associated with a higher probability of swarming or serve as warning signs in practice:

• Genetics and breeding line: swarming propensity can respond to selection, but its expression remains strongly dependent on the environment.
• Age and condition of the queen: colonies headed by young queens show less swarm preparation on average in several trials; the effect is probabilistic and depends on conditions.
• High density of adult bees: one of the early factors best supported experimentally.
• Large emergence waves: a large quantity of capped brood can produce many adult bees within a short period.
• Use of space: a shortage of functional space for adult bees, storage or comb building can be relevant; a shortage of laying cells alone does not explain the process.
• Strong nectar flow or rapid changes in resource flows: these changes simultaneously influence storage, comb building, foraging activity and cell use.
• Poor weather: it may delay departures that are already prepared and cluster them in time when favourable conditions return; an additional effect through increased bee density in the hive is plausible, but not demonstrated as a complete causal chain.
• Substantial liquid feeding during rapid colony growth: this can add an additional resource flow and alter cell use; the chain “syrup → filled brood nest → more swarms” has not been directly demonstrated.
• Volume, heat and ventilation: these factors can interact with colony state, but should not be interpreted as a simple thermal trigger.
• Swarm cells containing actively fed larvae: these show that the colony has entered a more advanced phase. Several advanced cells together with other converging signs indicate a high practical risk without guaranteeing departure on their own.

8. Preventing, controlling and making use of swarming

Adapt the method to the biological stage and to the actual objective — rather than treating every intervention simply as “swarm prevention”.

The most important practical lesson is this: the colony’s stage matters at least as much as the name of the method. Providing space before stable preparation becomes established, altering a colony already actively rearing queens, and recovering a swarm whose departure is imminent are biologically different tasks.

8.1 Begin by defining the objective

• Prevent: reduce the probability that stable swarm preparation becomes established.
• Alter preparation already under way: markedly change the adult population, the next emergence wave, brood, queen, egg laying or spatial and social organisation.
• Control the loss: avoid losing the queen and bees while the swarming dynamics persist. Preventing the loss of a swarm is not the same as preventing swarming.
• Use the reproductive dynamics: deliberately use colony division to form young colonies, artificial swarms or other increase.

8.2 Prevent early: queen, space and growth

The planned use of young queens has direct experimental support. Forster (1969) observed markedly less swarm preparation with young queens under the conditions of his trial; Hauser and Lensky (1994) likewise reported fewer swarm cells with younger queens. This is not a guarantee, but it is a supported preventive lever.

Sufficient space is likewise biologically relevant — but not in the form of a simple rule expressed in litres or solely as increased laying area. Expansion must take place early enough and take account of the actual population, brood close to emergence, storage areas and comb-building activity. Current Swiss recommendations include adapting brood-box volume to colony strength, adding supers in good time and removing bees or brood to form young colonies as preventive measures.

Allowing drone comb to be drawn may form part of spring management. Drone brood removal, by contrast, primarily serves to reduce Varroa reproduction and should not be presented as a reliable swarm-prevention method on its own.

Reversing boxes, moving individual frames or providing shade in summer are also widespread practices. These interventions can alter occupation of space, comb-building activity, temperature and movement within the colony. Their practical use can be meaningful; their specific effect on natural swarm departure is, however, less well isolated experimentally than the preventive effect of young queens.

A distinction should also be made between planned requeening before the swarming period and acute replacement, removal or caging of the queen in a colony already clearly engaged in swarm preparation. The preventive benefit of a young queen does not demonstrate that late requeening reliably terminates advanced preparation.

8.3 Removing queen cells: an important tool, but not a demonstrated reset

Removing queen cells prevents the immediate development of the queens concerned. It does not, however, demonstrate that the colony’s reproductive state has disappeared. Repeated inspections are therefore essential. Current Swiss practice recommends, when this strategy is chosen, removing all swarm cells every 7 to 9 days.

This interval is a management recommendation. It does not demonstrate that a particular inspection rhythm biologically “switches off” advanced swarm preparation. If new cells are rapidly constructed, that persistence should itself be regarded as information about the state of the colony rather than only as a problem of missed cells.

8.4 Young colonies, artificial swarms and division: genuinely changing colony demography

Removing brood and bees changes far more than the number of free cells. Depending on the method, the adult population, the next emergence wave or both are reduced. Maucourt et al. (2018) observed less swarming in donor colonies after young colonies were formed, without isolating the component responsible for the effect. Radtke (2010), by contrast, showed that removal of capped brood alone cannot be regarded as a universal reset.

Clearly defined divisions are therefore particularly useful when it is known precisely where the queen, brood, adult bees and foragers remain. This applies to brood splits, artificial swarms, temporary division using an intermediate board — known in German-speaking practice as the Zwischenableger — and flight nuclei.

For Swiss procedures see also Practical Guide: 1.4. Overview of methods for establishing young colonies, Practical Guide: 1.4.2 Artificial Swarm and Practical Guide: 1.4.7 Colony Multiplication from Swarming Impulse.

8.5 Artificial swarm: anticipating natural colony division in a controlled way

With an artificial swarm, a new mobile founding unit is deliberately created. At an advanced stage, such a controlled division may be biologically more coherent than attempting to restore the earlier state of a colony already deeply engaged in swarm preparation.

One practical sequence is:

1. choose the queen: the old queen or a new selected queen;
2. place a sufficient mass of bees in a well-ventilated swarm box;
3. in variants using cellar confinement, allow a stable cluster to form under cool, dark and very well ventilated conditions; duration depends on the method and circumstances;
4. hive on foundation or other comb-building surfaces and feed only according to need and nectar-flow conditions;
5. if the unit is genuinely broodless, use this period where appropriate for Varroa treatment in accordance with the current Swiss strategy and authorised product instructions;
6. subsequently check queen acceptance and activity, comb building, food stores and development.

The precise procedure depends, among other things, on whether the artificial swarm is established at the same apiary or elsewhere and whether a new queen is introduced. The corresponding practical guide should be used as the reference for the chosen variant.

8.6 Demaree and brood distancing: changing organisation while retaining colony strength

The Demaree method does not simply aim to weaken the colony, but to reorganise brood, queen and space. Typically, the queen remains below with sufficient available comb area, while a large part of the brood is moved to an upper section separated from her by a queen excluder and, depending on the variant, by honey supers. This simultaneously alters local bee density, brood care, contact with the queen, bee traffic and available comb area.

Demaree: a well-established practice for spatially reorganising the queen, brood and workers. The exact magnitude of its effect at different stages of swarm preparation remains insufficiently quantified.

The method has long been established in practice. It would nevertheless be excessive to claim that the bees “simply believe they have swarmed”. Its effect may result from several components being altered simultaneously. Checking for emergency and other queen cells in the brood section separated from the queen is particularly important.

The same applies to temporary splits and other forms of brood distancing: practical experience is abundant, while modern comparative trials distinguishing among stages and using natural swarm departure as the endpoint remain rare.

8.7 VIRDIS: preserving the future population rather than removing it

VIRDIS is biologically interesting because capped brood is moved within the same colony. The future workers therefore remain in the production colony, while brood distribution, comb-building surfaces, the queen’s area and local bee densities are profoundly altered (Colombari, 2019). Its logic thus differs from classic demographic removal.

The method is supported by professional experience, but not by a sufficiently robust controlled trial isolating its specific effect on natural swarm departure. This evidence gap is not evidence against the method; it means that its average effect and the stages at which it is optimal cannot yet be quantified reliably.

Weather dependence is important in practice: when available volume is greatly increased, it should be checked during a prolonged return of cold weather whether the colony actually occupies this additional volume and can access its food stores functionally. If necessary, volume can be reduced temporarily.

8.8 Caging the queen: local experience and biological plausibility

The Sion beekeeping section (ApiSion) has practical experience with temporary caging of the queen in a Scalvini-type cage when swarm preparation is already clearly under way. The protocol seeks to alter brood development and use of space substantially while retaining the queen and adult population within the same colony.

Cage the queen in a suitable cage within the brood nest, in an area well occupied by bees. Maintain sufficient storage space so that cells progressively becoming available are not immediately filled with nectar during a flow. Carefully remove all existing swarm cells. Inspect the colony thoroughly again after approximately five days and remove any newly constructed queen cells. This interval belongs to the ApiSion practical protocol and is not a universal biological rule. From approximately fourteen days onwards, reassess the colony: remaining brood, queen cells, areas becoming available, stores, bee density and overall condition. Release the queen when the overall situation is judged favourable, or extend the caging period if the chosen protocol and circumstances justify doing so.

The cage probably does not act as a direct switch for the swarming state. Depending on cage design, unrestricted laying is interrupted or greatly reduced, while the existing brood continues to develop and progressively emerges. The protocol therefore simultaneously alters continuity of egg laying, the amount of very young brood, the next emergence wave, progressive availability of cells, the relationship between nurse bees and larvae, the reproductive physiology of the queen and — when cells are removed simultaneously — the ability to complete new queen rearing.

Queen ovarian function is physiologically plastic (Aamidor et al., 2022). In another context, prolonged queen caging has also been used to produce a controlled brood interruption whose consequences depend, among other factors, on the timing of the intervention (Kovačić et al., 2023). These findings make the protocol biologically plausible, but they do not constitute a direct trial of the ApiSion method against natural swarm preparation already under way.

If caging is extended to nearly three weeks, practically all the worker brood that was present at the beginning of the intervention has had time to emerge. If the colony is genuinely broodless at that point, this window can additionally be used for an oxalic acid treatment against Varroa destructor, provided this is consistent with the current Swiss Varroa-control strategy and the authorised instructions for the product used. This potential synergy does not, however, demonstrate that the brood interruption alone is the mechanism responsible for any effect on swarm preparation.

For further reading: New method to suppress swarming behaviour.

8.9 Queen clipping and swarm recovery: controlling loss rather than preventing swarming

Clipping one of the queen’s wings can prevent a departing prime swarm from carrying its queen normally. The swarm may then return or regroup nearby. The method does not eliminate swarm preparation; it gives the beekeeper time and may facilitate recovery of the queen or swarm (Simpson, 1963; Forster, 1971).

The same principle applies to well-positioned bait hives or swarm boxes: they can help recover or channel a process that is already under way, but they do not prevent its biological preparation.

8.10 The practical decision rule

Swarming is not an error on the colony’s part. It is its natural mode of reproduction. The beekeeper’s skill therefore lies not in “fighting” swarming as a matter of principle, but in deciding early enough when to prevent preparation, when to alter a process already under way, when to control loss and when to use colony division to establish a new colony.

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See also:

• Understanding Swarming
• Practical Guide: 4.7.5. Managing the Swarming Impulse
• Swarm prevention
• Queen Cells
• Practical Guide: 1.4.7 Colony Multiplication from Swarming Impulse
• The mechanisms of natural swarming

Selected scientific sources

• Aamidor, S. E., Cardoso-Júnior, C. A. M., Harianto, J., Nowell, C. J., Cole, L., Oldroyd, B. P., & Ronai, I. (2022). Reproductive plasticity and oogenesis in the queen honey bee (Apis mellifera). Journal of Insect Physiology, 136, 104347. https://doi.org/10.1016/j.jinsphys.2021.104347
• Allen, M. D. (1965). The production of queen cups and queen cells in relation to the general development of honeybee colonies, and its connection with swarming and supersedure. Journal of Apicultural Research, 4, 121–141. https://doi.org/10.1080/00218839.1965.11100115
• Colombari, L. (2019). Gestione della sciamatura: metodo “Virdis”. L'Apis, 4/2019.
• Combs, G. F. (1972). The engorgement of swarming worker honeybees. Journal of Apicultural Research, 11, 121–128. https://doi.org/10.1080/00218839.1972.11099711
• Fell, R. D., Ambrose, J. T., Burgett, D. M., De Jong, D., Morse, R. A., & Seeley, T. D. (1977). The seasonal cycle of swarming in honeybees. Journal of Apicultural Research, 16(4), 170–173. https://doi.org/10.1080/00218839.1977.11099883
• Forster, I. W. (1969). Swarm control in honey bee colonies. New Zealand Journal of Agricultural Research, 12, 605–610. https://doi.org/10.1080/00288233.1969.10421245
• Forster, I. W. (1971). Effect of clipping queen honey bees' wings. New Zealand Journal of Agricultural Research, 14, 535–537. https://doi.org/10.1080/00288233.1971.10427116
• Grooters, H. J. (1987). Influences of queen piping and worker behaviour on the timing of emergence of honey bee queens. Insectes Sociaux, 34, 181–193. https://doi.org/10.1007/BF02224083
• Hauser, H., & Lensky, Y. (1994). The effect of the age of the honey bee queen on worker population, swarming and honey yields in a subtropical climate. Apidologie, 25, 566–578. https://doi.org/10.1051/apido:19940607
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