Organizing Bees on Pasture (part 1)

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Taranov (1967) explains that when a bee returns to the hive from collecting nectar, it gives it over to young bees who store and process it because they have a greater ability to convert complex sugars into simple ones. We will see later if that is the case. Bees produce honey by secreting the enzyme (protein) invertase, which converts the complex sugar from the nectar (sucrose) into simple sugars (glucose and fructose). This process is called sugar inversion. According to M. V. Žerebkin and I. Jakovljeva (1970), shafts have the greatest inverting ability during the summer and the main grazing season.


Although bee behavior in and out of the hive during nectar collection is well studied, beekeepers are not well familiar with this behavior, since they think that it is not of great practical importance. The truth is quite the opposite. By understanding how bees behave during grazing we can choose the most effective beekeeping technique, which will yield the best results, or at the very least won't harm the bees. We have all read about the recommended starting date of the optimal period for the development of communities for the main acacia pasture (the date that falls on the 51st day before the beginning of flowering of the acacia). We certainly have to keep that period in mind, but according to the latest research, we should know that more attention should be paid to the beginning of the second half of that period. About that a little later. 


According to new recommendations based on more recent scientific data, a specific type of queen stimulation for increased laying should begin about 40 days before the main grazing begins. Of course, it is an open question whether the colonies should be stimulated in any way in the spring, but this topic will be debated for a long time because the dogma among beekeepers is extremely strong. Keep in mind that the preparation of communities for grazing is not covered in this text. The goal is to understand what age structure the bees need to make the best use of the pasture. 


Taranov and Jazikov asserted in 1967 that on an abundant buckwheat pasture, the most honey was brought by the colonies whose queens laid most intensively 20 to 30 days before the start of the pasture itself, although the queens of other colonies laid significantly more eggs during the late winter and early spring when the development of the community was just beginning. This indicates that young and middle-aged bees are actively collecting nectar. This study was likely forgotten because other data that would have shed light on the entire problem was missing. 


To move forward with this article, a couple of basic things should be remembered. When bees need to go out into nature to gather resources, they shed excess mass, causing some internal organs to shrink and degenerate. Wax glands, which are 100 to 120 micrometers in size in young bees, are reduced to 12 to 15 micrometers in size. Pharyngeal glands are shrunk from 130 to 62 micrometers. The volume of the middle intestine is reduced from 23 cubic millimeters to 8 to 9 cubic millimeters. This makes room for the honey bladder to expand, allowing for the storage of up to 65 mg of nectar. When the honey bladder is maximally filled, the bee carries nectar that represents more than 2/3 of its mass. The body's protein content is high in young bees while declining in field bees, except for the breast, where it increases because that is where the muscles for flight are located. The content of carbohydrates and glycogen reaches its maximum in field bees because these substances are a source of energy for flying. Field bees have a more developed nervous system than house bees (Janko Božič, 1998). The mass of the field bees is reduced by 25 percent on average, so the field bee has an average mass of 80 to 85 mg. In any case, the mass of bees, first of all, depends on how the bees were raised - on high-quality natural food or on surrogates imposed on the bees by humans. Yield depends a lot on the average mass of bees in the community during the main grazing period. Taranov showed that a colony with an average mass of bees from 62 to 85 mg yields 17.3 kg of honey, from 86 to 90 mg yields 20.4 kg of honey, from 91 to 95 mg yields 21.8 kg of honey, and from 96 up to 100 mg yields 24.4 kg of honey. The average mass of bees in a single colony directly depends on the number of house bees, because the hives are already lighter than the average. This is proof that the community brings more honey if there are fewer field bees. That probably sounds strange now, but you will see what it is about in the following paragraphs. We can see that the yield of colonies with the highest average mass of bees is 41% higher than the colony with the smallest average mass of bees. After this information, I think that every beekeeper should think twice before giving any kind of artificial food to the bees.

Bees collect nectar from various types of flowers. Nectar can contain from 5% to 80% of sugar, usually from 35% to 45%. Sucrose (so-called white table sugar) is the predominant or only type of sugar in the nectar of many plants. In some plants, the proportion of sucrose in the nectar is equal to the proportion of monosaccharides (glucose and fructose), and in some plants, glucose and fructose dominate. There are traces of other types of sugar in the nectar (maltose, melibiose, raffinose, melicitose). For example, linden nectar is dominated by sucrose, from 50.92% to 66.56% (E.V. Kučerov, S.M. Siraeva, 1983). Nectar also contains nitrogen compounds, organic acids, fats, minerals, vitamins, and aromatic substances, but all these components together do not exceed 2% of the total amount of secreted nectar (Lesley J. Goodman, 1998).


According to Taranov, the nectar-gathering bee, upon arriving at the hive, hands the nectar to the young bees, who further process it and store it in the comb because they have a greater ability to convert complex sugars into simple sugars. We will see later if that is the case. The bee secretes the enzyme (protein) invertase, which converts the complex sugar from the nectar (sucrose) into simple sugars (glucose and fructose) and thus begins to make honey. This process is called sugar inversion. In the works of M. V. Žerebkin and I. N. Jakovljeva (1970), it is stated that the inverting ability of the shafts is greatest during the summer and the main grazing season. Also, according to the data of Simpson (1957) and Žerebkin (1965), invertase which is secreted by the pharyngeal glands is most active in bees that are around 20 days old. All in all, these are the bees who have started the second part of their life and the name young bees suit them less, because in summer the maximum life span of bees is up to 36 days, and according to new research, it is about 3 to 4 weeks in the period of greatest activity.

Lebedev told us that on poor grazing, the field bees put the nectar they brought into the combs themselves. However, with abundant grazing, a special group of young and middle-aged nectar-receiving bees appears in the community. They have maximally developed pharyngeal glands that secrete a secretion with sufficient amounts of invertase. When processing nectar, they add this secretion to it. The inverting ability of invertase in house bees who store nectar is 4 to 5 times higher than in brood feeders.


After the return of the bees from the pasture, the nectar recipients taste the nectar from different plants and the different bees and can compare its sweetness and then they reorient themselves to the field bees that bring sweet nectar. The field bees with relatively concentrated nectar are quickly emptied (in less than 40 seconds), and they are then stimulated to perform the appropriate dance and recruit the other field bees toward the pasture. In contrast, the field bees that bring less concentrated nectar are taken up more slowly by the recipients and they even often have to offer it to several female recipients (who are not too interested in insufficiently sweet nectar). Such bees are not stimulated to recruit other bees for their pasture, so they can be recruited for some stronger and better quality pasture. However, if the hive overheats due to external heating, there is a great demand for rarer nectar or water by the bees that regulate the microclimate in the nest. That's why, in those moments, the preference is given to field bees that do carry not as sweet nectar, which is abundant with water. Thus, field bees will now be increasingly recruited to bring watery nectar or water, until the thermal crisis passes (Thomas D. Seeley, 1995; M. Lindauer, 1971; Lesley J. Goodman, 1998). This behavior is conditioned by the bees' ability to determine the concentration of sugar in the nectar. This ability is almost unbelievable. With antennal and tarsal receptors, bees can register a sugar concentration of 0.06%, but the role of such a fine sensation in collecting nectar is still unclear to scientists (J.G. Stoffolano, 1995; Lesley J. Goodman, 1998).

Dr. Karl Ritter von Frisch, who deciphered the speech of bees - bee dances, thought all his life that the so-called bee dance does not say anything to the bees, forgetting that nature does nothing in vain. But Thomas D. Seeley, professor of biology at the Faculty of Biological Sciences at Cornell University in the USA, managed to solve this mystery. He noticed that the bee's courtship dance serves to remove the "bottleneck" during the increase of nectar intake into the hive when the necessary number of female recipients is lacking and that the dance recruits other bees to perform this function. In nature, there is no analogy to the removal of female recipients, but the bee dance occurs when grazing is intensified. Then there is a lack of female recipients, since the influx of nectar is very large, and the old number of female recipients cannot physically take it.

In 1991, Seeley performed the final experiment. He took the test hive to the Adirondack National Park, where there is no pasture and the only source of nectar was a feeder at a certain distance from the hive, where the bees filled the honey bladder to the maximum. When a field bee found the recipient in no more than 20 seconds, the bee only performed the dance that shared the location of the pasture. When a bee needed more than 40 seconds to find the recipient, it was more likely that the whole bee dance was performed. Seeley found something else very interesting. When 3 bees per minute returned to the hive, the dance was not performed, and 550 bees performed the work of the receiver during the entire day! The next day, when the dosage of syrup was increased in the aforementioned feeder when more than 25 bees returned to the hive per minute, more than 15 dances were performed (meaning that there were no receivers), although at that moment more than 2,000 bees were performing the function of receiving nectar, which means that there were not enough of them! However, these figures do not tell us what percentage of bees go to pasture, and what percentage performs the function of nectar processing and storage. But we can confirm that ourselves.


L. Bomus claims that traveling bees make up 27.3% of the total number of bees and that the main burden of nectar storage falls on domestic bees. Klaus Wallner and Ralph Büchler (2003) think similarly, considering that there is about 30% of them. Lebedev believes that there is no less than 50% of them in the strong pasture. A. N. Efremov (1966) shows that this percentage is even lower - about 15%, which, as you will see, is much closer to the truth, although the percentage changes depending on the situation. This is supported by the fact that the bee delivers nectar that is taken by 3 to 4 recipients, and in heavy grazing even from 10 to 12, when the bee stays in the hive even longer. This is a consequence of the so-called social exchange of food, although in this case, it has a much broader meaning, as you will soon see. This is also supported by the fact that Lindauer (1954) reported based on research - that the composition of the honey bladder contents of house bees and traveling bees within the same colony is almost identical. According to Taranov, the speed of nectar delivery is different and ranges from 20 seconds to several minutes, which increases especially during intensive grazing, when the field bee still has to find such a large number of recipients. And in the strong pasture, the honey bladder of the bees is even fuller. Of course, the fact remains that the data on the number of field bees is extremely relative and depends on a large number of factors. Nevertheless, there is a way to establish an approximate value for a given biological-seasonal population of the bee community. The information about the number of field bees expressed numerically does not mean anything, especially in practice. It is important to conclude that it is necessary to have as many nectar-receiving bees as possible in the hive, ie. bees closest to them in terms of age (physiological condition), so that in the event of a need for a larger number of recipients, they could easily help and thus increase the degree of use of the pasture.

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