Bee population management (Part I)

Basic information:

In beekeeping, for the final production results, whatever their nature (honey, pollen, royal jelly, etc.), we always have to manage 3 equally important values simultaneously:

• bee population (characterized by size, number/quantity, age),
• queens (characterized by hereditary traits transmissible to daughters, dynamics of prolificacy – also genetically inherited -, phenotypic value, good or poor production condition depending on age, feeding, health, etc.)
• honey base.

Bee population is indispensable for whatever purpose we keep bees. It often needs to be prepared so that it is available at the right time and of the right age for the purpose. For example:

• for honey harvesting we need honey bees that are 16-20 days old,
• for the secretion of royal jelly, as well as for the production of buds or brood rearing we need young bees, between hatching and 16 days of age;
• For pollen collection we need sufficient pollen-collecting bees, plenty of (uncapped) larval brood and of course the nests that maintain the larval brood.

Sometimes we can find ourselves, by natural causes, with a large population of bees at a time when we don’t need them and at an age that doesn’t suit our purposes. If we do not use this population for some purpose, whatever that purpose may be, we will run out of this population anyway because bees have a limited age. The most practical use of this population is for the production of biological material: artificial swarms, queen queen rearing, mating nuclei population.

Most of the time, however, there is a need to prepare the bee population we need for the time when it is needed in a directed way. For new population production we need:

– suitable temperature between 20 and ^30°C;

– enough adult bees to cover the brood;

– space for nesting (empty honeycombs in the nest);

– quality queens;

– last but not least, adequate nutrition: on the one hand, an optimal amount of nectar or syrup with water (enough to keep them from being hungry, but not too much to block the nest), and on the other hand, pollen of the highest quality (fruit trees, pesticide-free rape or mustard, hay) or a quality pollen substitute (complete in terms of the bees’ nutritional needs, balanced, with the best possible digestibility).

All our approach must take into account the seasonal dynamics of bee families and its stages: overwintering, early development, spring development, peak, and preparation for overwintering (Figure 1).

Without dwelling too much on these, we should mention that:

• Overwintering is a relatively passive state of keeping bees without brood rearing. Its quality depends on preparation for overwintering, which we will come back to, and genetics;
• early development starts in winter when brood growth begins, in the absence of foraging, and involves a higher consumption of nutrient resources, variable depending on bee genetics and ambient temperatures. Nutrient resources may or may not be available to the population, and may be of better or poorer quality, depending on the conditions of preparation for overwintering and the quality of the beekeeper’s interventions through supplementary feeding.
• Spring development can be slower or more rapid depending on family genetics. It occurs with very high consumption, but during periods of natural nutrient abundance in our area, which also may or may not be affected by weather and human-induced environmental changes. That is, in normal years it does not require additional feeding, but in years with cold springs or in poor areas, feeding becomes necessary. It tends towards a peak that culminates in the gnawing instinct.
• The natural conditions for development last until the summer solstice (June 20-30), after which the queens’ tips decrease due to the shortening of the light period. Possible positive que queen bridging forces exist in very young queens and/or in newly formed swarms, especially in the absence of brood and with an abundance of adult dowitchers.
• The foraging instinct usually (except in situations of lack of living space) indicates a maximum possible bee population for that queen and varies widely within species, within breeds and from one area to another. It can occur at any time of the year, especially before July 1, but sometimes also after.
• The period of preparation for wintering is characterized by the gradual decrease of the queens’ bridges, and on the other hand by the accumulation of vitellogenin (as a substance of the fat body) in the body of the bees of the last generation of the season. This period is increasingly problematic in terms of field conditions, which are moving further and further away from the nutritional requirements of the bees – while the demands of those who keep bees are being defined in an increasing direction. For quality overwintering, interventions through supplementary feeding are from year to year increasingly necessary.

A very valuable study of the seasonal dynamics of bee families was done by Mihai N. Stefănescu and his collaborators in 1985-1987 and published in the magazine Romania Apicolă together with the image in Figure 2 under the name “Curba de roire la abeine”. This image was subsequently taken up by various other publications, but without the corresponding explanations. The main conclusions of this study (of course taking into account the genetic make-up of the bee population at the time, which may be different from what we have available today) are:

1. 1. The most efficient development of a bee family is achieved when it has a population of 1.5-2 kg. If the population is less than 1.5 kg, it cannot take care of all the larvae a queen can produce. Of course, maximum efficiency can only be achieved under conditions of optimum temperature and quality food available.

1. 1. If the population exceeds 2 kg, already some of the bees will be busy accumulating food reserves, which makes them not effectively involved in brood rearing. Theoretically, the colony would not need additional foraging (ONLY IF the flora, area and temperatures provide sufficient pollen and nectar) or sometimes foraging can even hinder the tip by blocking the nest.

1. 1. The instinct to swarm is triggered after a certain amount of adult bees/family, called the “swarming threshold”, which in their situation was just over 4 kg of adult bees/family.

Note: The actual threshold differs from case to case, depending on several particular situations: genetic, characteristic of the honey area, working techniques and even variables from one year to another, but it must be guessed by the beekeeper based on experience with his own genetic material and the area.

For example: if one family builds a swarming hive at the threshold of 4 kg of bees, maybe another family (or the same one the following year) does not build one at 5 or 6 kg of bees, or another builds one at 3 kg of bees. Some families swarm after they have built 2-3 quiet change apiaries, and others build apiaries and then self-destruct them at any small change in the environment or give up rebuilding them after they have been destroyed by the beekeeper. Some families give up swarming after 1-2 combs of capped brood have been taken away, others only after the loss of 4 combs, and still others need to have all their brood taken away. The situations can be different from one year to the next even if the same queens are kept, and definitely differ from one honey area to another. The main technique to combat the instinct to brood remains genetic improvement and knowledge of the tendencies of the biological material that each one possesses.

• • Although the harvesting yield of families stronger than the gnawing threshold is theoretically better, we cannot practically operate with such families (except possibly by clapping the queens, which requires too much labor). They have to be kept as strong as possible during harvesting, but below this “threshold”.

• • The proposed methods for efficient exploitation are:

• • removing combs with capped brood from families in danger of exceeding the gape threshold (they are given to weaker families, resulting in a power balance at hive level or used for the production of new biological units) and possibly
  • replacing them with beehives with larval brood from poor families with prolific queens to use the working capacity of the surplus adult population;
  • strengthening weak families with frames of capped brood covered with bees in order to make families large enough for harvest time. These may come from families that are too strong or from other families that are intentionally weakened by being removed from the flock.

Note: Working with capped brood has the desired influence if done at least 25-30 days before the intended harvest. If the gape threshold is reached only a few days before or during the harvest, headed broods may be removed from the family knowing that the influence on the family’s ability to harvest will not be felt until at least 15 days after the operation. If the gape threshold is reached more than 30 days before the next culling, the weakening technique is to remove the predominantly young adult population and the family will be rebuilt on the basis of the young.

• Focusing on the management of acacia harvesting they concluded that in their case:
  • Families wintering with less than 2 kg of bees (6 Dadant frames or 8 ME) are not sufficiently stocked for acacia foraging unless they receive stock from other sources;
  • Families with 2.1 kg of bees (7 Dadant combs or more than 9 ME) at the end of winter have maximum efficiency in acacia harvesting;
  • Families with more than 8 Dadant beeches reach the threshold of more than 4 kg before harvesting, thus compromising their efficiency. It was therefore necessary to apply the above-mentioned weakening techniques.

Note: The data are indicative because the reality differs depending on many zonal factors, bee genetics and it is also necessary to adjust the techniques according to the particular conditions of each year.

• • Recommend raising queens in families of more than 2 kg of adult bees;

• • Recommend introducing queens only in units of less than 2 kg of adult bees.

(2 kg of adult bees occupy about 8 Dadant combs or 10-11 ME combs in summer)

Our recommendations on bee population management

If efficient honey production is aimed at: Taking into account the nectar harvesting calendar, the above indications can be followed with significant adjustments according to the particular conditions of each farm (area, flora, year, working techniques, genetic characteristics).

In particular, we aim to harden off families with capped brood 4-6 weeks before the start of harvest, and then to remove capped brood around the start of harvest if the families show signs of reaching the brood dew threshold (i.e. if they start to tip in early buds).

Supplementary spring feeding is done with pollen substitute or pollen from your own hive and if necessary with sucrose-free energy cakes from the onset of laying until the first pollen in nature.

Ensure a warm microclimate in the hives by restricting the population to as few combs as possible, sheltering from the wind, organizing common flocks with other families, keeping well populated families (merging if necessary).

Supplementary feeding with syrup (50% water) is done during the flight period of the bees, following the oscillations of the scale. The aim is to provide the necessary liquid food for the larvae and pollen collection. The brood combs are inspected periodically to see the nature of the crop – nectar or pollen, the amount of liquid food in the combs – essential for lar larval development, the amount of milkweed around the larvae. Stop 7-10 days before an expected nectar crop. Stop if nectar-based scale increases above 0.

It is recommended to keep at least 5-6 kg of bee-accessible capped food in the combs.

Enlarge the nest in one direction only by adding empty combs, knowing the location of those with food left over from the previous year to avoid extracting their contents under any circumstances. We do not recommend ‘breaking the nest’ as a method of enlarging the space. When the first crop emerges, add mules over the Hanneman’s gratia and enlarge nests according to the needs of the families only if young fledglings appear on the comb near the diaphragm.

Do not deplete production families unless there is imminent necrosis or, with a high risk of honey adulteration due to the need for additional feeding, if there follows a period of at least 2-4 weeks of empty picking (guideline: the picking population recovers in 2 weeks from dowitchers, the adult population of all ages in 3-4 weeks from brood, and the removal of brood, recommended shortly before or during picking, has repercussions with a decrease in the adult population after 15 to 40-50 days).

Any intentional weakening of production families should be avoided as far as possible. It is also advisable to avoid feeding carbohydrate feed just between harvests. This can only be done in the absence of harvest confirmed by weighing scales and should be carried out carefully, as much as is consumed, so that no surplus of sweet feed remains in the combs in danger of mixing with nectar.

Work is currently underway to develop a type of protein feed that can be administered between harvests without the danger of adulterating the combs and hive products.

For the production of biological material, especially adult bees (which can be used for various purposes):

Honey production families shall not be used as a source population, except for surplus population, if this is obligatory due to imminent dew or at the end of the production season.

The best way to work is to designate a flock of bees maintained and operated solely for this purpose. In any production apiary, a sector can be formed with a part of the hives exclusively for breeding to replace spent biological material and for development.

They feed abundantly to achieve peak performance and any resulting products are not used in human food.

The season when we recommend intensive beekeeping is from April to July.

In all sectors of biological production, whether queen production, drones, worker bees or swarm development, feeding is done at will with protein feed without relying on any environmental pollen source. This either does not exist at the quality level required by intensively exploited bees, or cannot be collected in sufficient quantity by a population busy caring for larvae.

Use as prolific queens as possible.

The aim is to maintain bee producing colonies in the range of 1.5-2 kg of adult bees, equivalent to 6-8 Dadant combs or 8-11 fully covered ME combs.

Carbohydrate feeding is done with syrup with 50-60% water and 40-50% dry matter or energy cakes. Depending on the situation indicated by the check weighing scales, plenty of carbohydrate feed is given so as not to block the cube. Daily intake is normally over 400g dry matter (carbohydrate)/day (part may be from nectar collected from the environment) in such a colony. Syrup or energy cake made of glucose, fructose and moderate proportions of sucrose, supplemented with vitamins and minerals, is preferred.

Such colonies of 1.5-2 kg of bees from which capped brood is raised can be successfully used for pollen production.

On reaching the proposed maximum growth of 2 kg or 2.5 kg for very prolific queens, a quarter of the combs are removed in the first case or the 2.5 kg colony is split into two smaller colonies of 1-1.25 kg and 1.25-1.5 kg (the queen remaining with the larger one on the original site). The remaining empty space is filled in with built or artificial empty combs. On a case-by-case basis, the combs with the resulting population can take the following directions:

– formation of new colonies producing adult bees (from 3 colonies of 2 kg and a mated queen a 4th colony is formed or from one of 2.5 kg + a mated queen – 2 of 1.25 kg) preferably on another hearth;

– strengthening production families with population;

– training of queen queen or jelly producing families;

– populating mating nuclei (with frames of the same size as the original hives);

– formation of artificial swarms with capped young to develop until the wintering season;

– Strengthening weak swarms that have quality young queens;

– forming units from which adult bees are produced by the following method: Fill a body with capped brood covered with bees. Place a Hanneman’s brood excluder and a body with a medium to weak colony with queen. The presence of the queen protects the combs from the building of life-saving haulms. The hatching population feeds at will on protein cakes. At the end of hatching, the bees are shaken off the combs, transported to another hearth and used to populate mating nuclei or to form swarms of packaged swarms. The top body with the colony can be left on the plinth without relocation. The combs can be reused or melted. These are usually devoid of honey, which is ascended into the queen body. Any honey extracted is used to feed the bees.

Excess adult bees can be shaken directly from part of the combs of a colony with more than 2 kg adult bees, taking care not to shake out the queen and leaving enough population to cover the brood. The adult population will be replenished by hatching bro brood. Don’t forget the mandatory feeding after harvesting adult bees!

Even if there are no major problems with Varroa mites during the period April-July when the biological material is being produced, it is good to consider controlling the infestation of this biological material with mites on the route of its exploitation.

Evaluation of Varroa mite infestation in colonies fed with Dulcofruct Bee Nutrition Science products revealed that while the natural mortality of Varroa mites is 22% of the population, the mortality in families where the cakes persisted for more than 12 days in the hives was 50% for Energetic Forte cakes (due to the thymol contained), 65% for a prototype cake not yet in mass production and 69% (between 64% and 76%) for families fed with Super Protein Cake. These products reduce the Varroa population and this is a further argument for their use in the production of biological material.

Prof. Dr. Daniel Popovici: Research and Development Manager