Observations at the hive entrance

A bee colony requires tranquillity throughout the beekeeping season, and probably even more so during the winter months. If an overly curious beekeeper opens the hive indiscriminately, the constantly disturbed colony becomes stressed. The behaviour of this superorganism changes: energy consumption increases, the reserves of its valuable fat body are depleted, immune defences against varroa and the viruses it transmits are inhibited, the development of the worker population and brood slows down, and the colony ultimately collapses into a vicious downward spiral (► Infernal cascade: Chronicle of a foretold death).

Careful observation at the hive entrance provides a great deal of information about the activity inside the hive. If the beekeeper takes the trouble to compare the alighting boards of several hives, they will quickly notice if « something unusual » is happening at one of them.

1. In Winter

In winter, a weekly or fortnightly check of the apiary makes it possible to ensure the hives are stable on their stands and that the entrance is clear (► Réussir l'hivernage).

More or less compacted snow may accumulate in front of the entrance; bees that have died naturally may accumulate against the inner face of the entrance grid and prevent workers from exiting. Clearing the entrance is essential for good ventilation and oxygenation of the hive and to allow flight activity.

At the onset of winter a colony may number 30,000 bees; at the end of winter it will number only 15,000–20,000 bees. It is therefore possible to find a significant number of dead bees daily (up to 50) at the entrance, on the alighting board, or on the layer of snow in front of the hive. By contrast, a very large number of dead bees on the alighting board of a single hive should raise suspicion of a situation requiring investigation (starvation, thermoregulation problem, disease…).

A few dead bees in the snow is normal.

Photo 1: More or less compacted snow may accumulate in front of the entrance grid. As long as the snow is powdery, it remains permeable to air and the bees' breathing is not seriously impeded. But once it starts to melt and risks freezing overnight, it may block the entrance, and it is advisable to remove it.
Photo 2a & b: Bees that have died naturally may accumulate against the inner face of the grid and prevent workers from exiting. A few dead bees in the snow is normal. This occurs mainly in well-populated hives and there is no cause for concern.

Regular checks of the apiary make it possible to spot any damage caused by woodpeckers, which hack at and sometimes perforate the full thickness of the hive wall in search of food. Not only is the colony disturbed and its fuel consumption increased (stress), but the workers that venture near the entrance are snapped up without hesitation. Polystyrene hives do not hold out long against the attacks of birds, including tits.

Photos 3 & 4: Woodpeckers sometimes perforate the full thickness of the hive wall in search of food.

When the temperature drops, the colony protects itself from the cold by forming a well-structured winter cluster — with its insulating outer mantle, its intermediate breathing layer, and its heat-production core, whose fuel consumption is optimised to ensure the bees' survival. This cluster is silent: it is difficult to hear a faint hum when knocking on the hive…

If a hum is spontaneously audible during a prolonged cold period, the winter cluster has probably not formed: either brood is being reared, or the colony is stressed and perhaps queenless, and needs to be inspected (intruder, mouse…).

Photo 5: On a calm day, listen at the entrance of a well-populated hive. Many will hear nothing at all. In that case, using a listening tube, one can easily discover how much they are being disturbed in their winter cluster rest.

When the temperature rises, the winter cluster breaks up; however, if it drops rapidly, the bees huddle more tightly together. The hum perceived comes from these movements. In both cases, an increase in respiratory activity is difficult to observe. The experienced beekeeper never welcomes a sudden temperature change in winter, nor one occurring between day and night, as it always causes higher food consumption.

The presence of a little condensation water on the alighting board, directly in front of the entrance, means that the colony is generating warm, humid air and is therefore alive and well.

Photo 6: When nights are still cold, the presence of condensation water on the alighting board often indicates the beginning of egg laying.

After a long period of confinement (cold, precipitation…), the bees take advantage of the first fine day to carry out their cleansing flight. The older bees that have been inside the hive for a long time, and the young bees that have never yet flown outside, combine their cleansing flight with an orientation flight — never venturing far from the hive entrance. Colonies that rear brood during a period of confinement produce considerable amounts of water by metabolising honey reserves. Nurse bees store a portion of this unwanted water in their intestines to control the humidity inside the hive and prevent the formation of mould.

As soon as conditions for the cleansing flight are present, the bees with distended intestines rush outside to empty themselves as quickly as possible. This is why a few brownish streaks of faeces are sometimes visible on the alighting board, on the hive walls, or on nearby surfaces (car bodywork, laundry on a line…).

Photo 7: After winter, cleansing flights take place at the beginning of spring, during which the faeces-filled bladders of the winter bees are emptied. In May, faecal spotting occurs when young bees have received too much pollen and too little water. Splashes of black faecal spots may indicate the presence of nosema. One can also distinguish pointed splash marks from sausage-shaped faecal traces.

If, on the other hand, the hive entrance is smeared with large quantities of foul-smelling excrement with dead bees stuck in faeces on the alighting board and in front of the hive, a dysentery disease (nosema) is probable. This situation occurs more frequently after a long period of confinement, when the temperature is cool and the humidity inside the hive is too high. The distended intestines of the bees favour the multiplication of the parasite Nosema apis as soon as the temperature rises somewhat during February. By contrast, during periods of poor weather at the end of the season, it is Nosema ceranae that can proliferate and cause dysentery. Finding bees lying on the ground in front of the hive or clustering in small groups unable to fly should prompt suspicion of nosema (► Maladies diarrhéiques).

Opening the hive confirms extensive contamination on the frame lugs, on the combs, on the inner walls of the hive, on the open mesh floor, and the presence of piles of dead bees. This colony has little chance of survival and must be treated or destroyed as quickly as possible to prevent contagion spreading to the entire apiary. The frames will be destroyed and the hive scorched.

Prevention:

Eliminate weak colonies
Keep colonies compact
Unite small healthy colonies
Renew frames regularly
Maintain cleanliness of watering points and do not place them within the bees' flight path
Focus breeding on healthy, disease-resistant colonies
Choose a dry, sheltered, warm location with good forage conditions (including pollen supply in spring)
Avoid large honeydew honey reserves when preparing colonies for winter
Ensure the bees have undisturbed winter cluster rest

Photos 8 & 9: After a long period of confinement, the distended intestines of the bees favour the multiplication of the parasite Nosema apis as soon as the temperature rises somewhat during February. By contrast, during periods of poor weather at the end of the season, it is Nosema ceranae that can proliferate and cause dysentery.

Control:

Prevention is the best control measure — there is no authorised veterinary medicine.
In cases of mild infestation, the best solution is to form an artificial swarm placed in a clean hive on foundation frames (► Practical Guide Emergency treatment 1.7.1. and 1.7.2. at www.abeilles.ch/varroa).
In cases of heavy infestation, destroying the colony and frames is the best solution.

If these bees hold their wings widely spread in a cross shape (K), it may be a case of acarine disease, caused by infestation with the parasite Acarapis woodi located in the thoracic tracheae and causing lesions of the wing muscles (hence the cross-shaped wing paralysis). The bees are no longer able to fly.

Cases of mild to moderate infestation are generally not very dangerous for the colony, but there is always a risk of the parasitosis increasing in severity.

Colonies rarely survive a peaceful winter; they risk dying of cold. Infested queens may survive and continue to lay, but their colony risks dying. If 20% to 30% of the bees are affected, the colony is doomed and must be destroyed. There is no authorised treatment. The only prevention is to avoid acquiring colonies of dubious origin.

Photos 10–11: Signs of infestation with the parasite Acarapis woodi: adult worker honey bee displaying the K-wing. Note how the hindwing is disjointed from the forewing, causing the hindwing to protrude from the thorax at a 90° angle, giving the wings and body a distinctive "K" appearance. (Credit: Honey Bee Research and Education Laboratory (honeybee@ifas.ufl.edu), University of Florida)

If, after a long period of confinement, the colony does not carry out its cleansing flight like its neighbours, various hypotheses should be considered:

The colony has not yet started rearing brood; the queen may be from a slightly later strain.
The colony may have been robbed as early as autumn and is in the process of collapsing.
It cannot fly out because the entrance is blocked by dead bees or other debris left by an intruder (mouse).
The colony may have died of starvation and cold, having been prepared for winter on too many frames, too far from the food stores.

If the cause of the absence of a cleansing flight is unclear, take advantage of the next fine day to open the hive carefully and look for open brood (proof of the queen's presence) or confirm the death of the colony (destroy frames, scorch the hive).

Photo 12: From late January/early February, the queen resumes egg laying and foragers bring back hazel pollen.

From late January/early February, the queen resumes egg laying, foragers bring back first hazel and then willow pollen, and water foragers are in full activity for the production of royal jelly by nurse bees. An elegant way to monitor the water requirements of brood-rearing colonies is to place a control watering point near the hives. The incessant activity of water foragers and pollen loads confirm brood rearing.

Photo 13: In late March, loads of shapeless grey or greenish pellets during the pre-flowering of birch/poplar/chestnut trees confirm that foragers are collecting their first propolis to maintain hygiene inside the hive (► Propolis).

2. In Spring

In spring, colony activity accelerates and fuel consumption increases sharply to maintain brood temperature above 34°C. Pollen and nectar/honey consumption follows the development of the open brood area (► Tout sur le nourrissement).

If bees deposit white, shiny sugar crystals on the alighting board, they have begun consuming the reserves from the outer frames and it is time to offer them 50% syrup to prevent the onset of May disease (► May disease). Nurse bees without sufficient water available can no longer digest pollen for royal jelly production. They fall in front of the hive in small, trembling clusters.

Photo 14: White, shiny sugar crystals on the alighting board may indicate a water shortage.
Photo 15: The presence of many yellowish faecal threads draws the beekeeper's attention.

The presence of yellowish faecal threads on the alighting board draws the beekeeper's attention. When pressure is applied to their completely full abdomen, a thick yellow to brownish excrement is expelled. Water should be sprayed quickly onto the bees in the bee spaces, or water provided via a supplementary feeder (warm, diluted 50% sugar syrup or pure water if the super is already in place (► Quelle eau pour nos abeilles).

Finding white pupae on the morning following a cold night means that part of the brood could not be kept warm by too few workers, and this cold-killed brood is being removed from the hive to prevent bacterial secondary infection. Lizards and birds will help themselves in passing…

Photos 16a & b: Finding white pupae on the morning following a cold night may indicate that part of the brood could not be kept warm by too few workers (► Sens et non-sens de la thermo-isolation des ruches).

The presence of a large amount of condensation water in the morning in front of the entrance confirms the good health of the colony rearing a substantial amount of brood. The foraging of large quantities of multicoloured pollen confirms the colony's vitality.

Photo 17: If bees are bringing back a lot of pollen, that is a good sign (► Reconnaître le pollen).

It is always useful to compare the activity of several hives in the same apiary to confirm regular colony development. A colony that brings in little or no pollen and whose forager flight is clearly sparse compared to adjacent hives should attract the beekeeper's attention. A more thorough colony inspection is necessary to clarify the cause of this delay. It should be kept in mind that a colony kept compact in spring will develop more rapidly than one that has too large a volume, which is difficult to heat.

On a fine afternoon with mild temperatures, one can observe dense flights in front of several hives, radiating in all directions, with clusters of bees on the hive face just above the entrance. These apparently disorderly flights are orientation flights of young bees learning the surroundings of their hive in preparation for their future role as foragers. They follow trajectories of increasing distance from the hive to memorise the foraging area and landmarks for returning home. This is the bee firework display. These flights differ entirely from swarming. When a swarm leaves the hive, one witnesses a genuine "pouring out" of bees, which is very brief — on the order of a minute — and whose sound resembles a roaring. The swarm flight is more or less compact and settles within about 10 minutes not far from the hive, forming a pear-shaped cluster hanging from a more or less elevated branch of a nearby tree.

Photo 18: Orientation flights of young bees learning the surroundings of their hive often take place in the afternoon between 14:00 and 16:00 and should not be confused with swarming (often between 11:00 and 14:00).

In the morning one can occasionally find a small white caterpillar on the alighting board. The wax moth feeds readily on the wax and pollen debris found on the hive floor (► La fausse teigne).

Bees tolerate adult wax moths and are unable to dislodge the pupae buried in their cocoons. The caterpillars, however, which move more slowly over the combs, are actively hunted and expelled from the hive — to the great delight of small birds.

Photo 19: The wax moth feeds readily on the wax and pollen debris found on the hive floor.

In the morning one can discover whitish, grey, or black concretions on the hive floor and alighting board, most frequently in spring due to cold snaps and poor nutrition. Chalkbrood (chalkbrood; ascosphaerosis) is a fungal disease that affects worker and drone brood. Contamination of larvae by the fungal spores leads to their death, desiccation, and the formation of chalkbrood mummies.

Stonebrood (aspergillosis larvae apium) is a fungal disease caused by fungal species of the genus Aspergillus: A. fumigatus, A. flavus, and A. niger. It causes mummification of the brood of a honey bee colony. These fungi are common in soils and are also pathogenic for other insects, birds, and mammals. The disease is difficult to identify in the early stages of infection. The spores of the different species have different colours and can also cause respiratory disease in humans and other animals. When bee larvae ingest spores, they can hatch in the intestine, rapidly developing to form a collar-shaped ring near the larval heads. After death, the larvae turn black and are difficult to crush, hence the name stonebrood. Eventually, the fungus emerges through the larval integument and forms a false skin. At this stage, the larvae are covered with powdery fungal spores. Worker bees clean the infected brood and the hive may recover depending on factors such as colony strength, infection level, and hygienic behaviour of the bee strain (this trait varies among different subspecies).

Ascosphaera apis causes a fungal disease that infests the larval gut. The fungus competes with the larvae for food, causing them to starve. The fungus then continues to consume the remaining larval bodies, making them appear white and "chalky".

If the colony is not too severely affected, providing protein in the form of pollen and 50% syrup can resolve the problem. Sometimes replacing the infected queen is necessary. In severely affected colonies, an artificial swarm is required, or even sulphuring of the colony to prevent contamination of the entire apiary (► Le couvain calcifié).

Photos 20–22: Chalkbrood (chalkbrood; ascosphaerosis larvae apium) is most often visible during wet springs. Hives with chalkbrood can generally be recovered by improving ventilation in the hive.

		During a nectar flow, bees may appear crowded at the entrance, disrupting the take-off and landing of foragers, and many pollen pellets may litter the alighting board. The hive entrance is certainly too narrow, and the entrance reducers should be opened to improve traffic flow.
Photo 23: If the hive entrance is too small, congestion can occur. Fanning bees block it and outgoing bees obstruct the path of heavily laden incoming bees. Over time, this lost time leads to a reduction in the honey harvest. However, too large an entrance encourages robbing.

If all activity suddenly ceases in a strong colony, swarming is imminent. The colony has built queen cells in which the queen has laid eggs, which may already contain queen larvae. These cells will soon be capped. To prevent swarming, an artificial swarm must be made without hesitation.

Photo 23a: If all activity suddenly ceases in a strong colony, swarming is imminent. This colony will swarm very shortly, perhaps within minutes. A primary swarm leaves the hive as soon as the first queen cell is capped. If it is raining at that moment or the temperature is not favourable, it waits for the first fine day. In a primary swarm, the queen almost always appears last.

Between 10 and 11 o'clock, you suddenly hear the roaring of the drones, which is unusual at that hour, and you quickly identify the colony from which they are coming. It is flying irregularly and pollen-laden bees are emerging from the entrance.

When walking slowly in front of the apiary in the evening, as the sounds of the day gradually fall silent, one can hear very distinctly the "toot" of a young queen through the hive entrance of colonies that have produced a primary swarm. The "quack" of queens still inside their cells is more difficult to hear. This colony will produce a cast swarm the following day or by the 3rd day at the latest. In a cast swarm as in a singing swarm, the queen appears first. Both emerge even if the temperature is less favourable, and both build worker cells exclusively for 3 weeks.

A colony that has not produced a primary swarm emits the well-known "toot". The queen of this colony died about two weeks ago, or was injured or killed during an inspection — which often happens. This colony will produce a singing swarm the following day (► Essaimage).

3. In Summer

In summer, when the internal temperature of the hive is too high, a large part of the colony leaves it, instinctively sensing various dangers (softening of the comb, collapse of combs laden with honey or brood). If the temperature continues to rise above 36°C, the brood suffers and may die. This dead brood decomposes in the cells, but must not under any circumstances be confused with foulbrood. The hive must be ventilated immediately and the varroa insert board removed if in place. This situation occurs most frequently in apiaries exposed to the midday sun with no protection against sunlight striking directly on the entrance.

		When the outside temperature rises above 30°C, a more or less large bee beard can be observed hanging from the end of the alighting board. The bees are bearding to offload the weight of the wax combs, which threaten to melt and collapse along with the brood and stores.
Photo 24: In summer when it is very hot, a bee beard in front of the entrance is nothing to worry about unless the temperature continues to rise above 36°C.

Other workers, the "fanning bees", brace themselves on the alighting board, head facing the hive entrance, body flat, wings beating constantly. The airflow produced in this way evaporates the water brought by the "air-conditioning bees" and lowers the temperature inside the hive body. The same phenomenon is observed when bees seek to reduce the moisture content of honey, just before capping and subsequent storage.

Photo 25: In summer, when the outside temperature is high, the "air-conditioning bees" lower the temperature inside the hive.

		This thermoregulation must not be confused with bees performing the "scenting" behaviour after hiving a recovered swarm or during orientation flight.
Photo 26: The Nasonov pheromone is released by worker bees to guide returning foragers back to the colony. To diffuse this scent, bees raise their abdomen, which contains the Nasonov glands, and fan vigorously with their wings.

The bees are clustered in front of the entrance, heads towards the hive, wings beating, but the tip of their abdomen is pointed upward and a gaping of the last abdominal segment is visible, allowing dispersal of the scent-marking pheromone produced by the Nasonov gland (► Phéromones royales).

4. In Autumn

In autumn, colonies prepare for overwintering. It is a period of profound change in colony behaviour. The drones have become useless mouths to feed, and the workers starve them before expelling them from the hive without ceremony or compunction.

If drones are being expelled, this is a sign that a queen is present in the hive. It is the ideal moment to requeen if the queen is more than 3 years old.

Photos 27 & 28: Expulsion of drones. Every colony with a queen expels its drones in August. Some time beforehand, the bees stop feeding these useless mouths in order to weaken them.

After a colder night than usual, larvae or white pupae can be observed on the alighting board in the morning. For the same reasons already mentioned in spring, brood that has died from cold is eliminated and expelled from the hive by house bees.

Observation of the alighting board sometimes reveals workers unable to fly, whose wings are deformed and atrophied. These bees were affected during their pupal stage by Deformed Wing Virus (DWV) transmitted by the varroa mite. This is a feared alarm signal, as the pressure of varroosis risks causing colony collapse even before the onset of winter. Monitoring the natural mite drop on the varroa monitoring board and applying a varroa treatment are imperative if the drop exceeds 5 per day (► La maladie des ailes déformées)!

Photo 29: Deformed Wing Virus (DWV) is an RNA virus that affects honey bees. Affected individuals display completely stunted wings as a symptom, preventing the bee from flying. (Source: KnackBockBlog | Seite 14, wordpress.com) (► La Résistance à Varroa).

In autumn, the colony has one priority objective: storing food reserves to survive the winter. Observing chaotic activity with fighting in front of the hive entrance, clusters of bees under the varroa insert board, at the gaps in the roof frame or the feeder, the presence of black and hairless bees (they lost their hair in the fighting), granular and sticky deposits in front of the entrance and on the metal grid allows robbing to be identified without hesitation. Sometimes the robbing is carried out by wasps: the spectacle is very discreet, but the incessant coming and going of these close relatives draws extensively on the colony's reserves without really triggering defence by the guard bees. The contributing factor is the presence or smell of honey or syrup at the apiary. Care must be taken when feeding with concentrated syrup and even more so with 50% syrup: the slightest drop fallen to the ground attracts foragers, and the robbing frenzy soon grips the entire apiary. To avoid agitation at the apiary, feeding is best done in the evening, when foragers are inside the hive. In the same vein, allowing super frames to be licked clean after extraction is a risky undertaking.

Where there is robbing, there are robbers and robbed. A weak hive whose guard bees cannot effectively defend their entrance will fall prey to a strong colony that seizes its food stores… but also to the potentially numerous varroa mites that exploit the immune decline to multiply and spread their load of viruses! Robbing is therefore a double-edged sword. The only true beneficiary is the phoretic varroa mite, which can change host and spread throughout the entire apiary despite the two summer treatments! A robbed hive must therefore be closed and moved away from the apiary to prevent fuelling the robbing frenzy and the transmission of disease. The survival of this colony is uncertain even before preparation for winter. It must be remembered that the robbing of a colony is not a disease in itself, but the consequence of the progressive collapse of a colony that is failing for various reasons.

In recent years, some beekeepers have become concerned about seeing their hives attacked more regularly and more severely by the Asian hornet. Hovering about twenty centimetres from the hive entrance, one worker of Vespa velutina nigrithorax regularly relieves another to capture returning foragers laden with pollen. The hornet dives on its prey, seizes it between its legs, and kills it with a mandible bite behind the head before carrying it to a tree to dismember it.

Photos 30–32: The danger of robbing is even greater in August than in April. Many foragers attempt to bring food this way before dying. The entrance must be reduced in time. Robber bees are remarkably persistent. Robbing by wasps is less spectacular but effective (► Le frelon asiatique arrive en Suisse).

Anecdote: on a day with a strong nectar flow, intense traffic takes place between the alighting boards of two neighbouring colonies; it runs along the hive facades, but may also take more roundabout routes. This is an indication of latent robbing. One colony is robbing another in the most civil manner. A screen placed between the hives is most often crossed or circumvented. The robbers even penetrate inside the hive. This latent robbing sometimes explains abnormally high honey yields.

Conclusion:

Each season offers the curious beekeeper the opportunity to observe scenes that must be correctly interpreted to understand what is happening inside the hive. By combining these entrance observations with reading the hive debris (► Les secrets passionnants de la lecture des déchets), a true mirror of life beneath the frames, one can refine one's hypotheses. If the crown board is made of transparent PVC (Plexiglas), observing the activity from above allows a quick assessment of colony development. The ultimate solution remains the connected hive (► Observations en temps).

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