Annotation
The continuing growth of losses of bee colonies from factors that are based on the infection of bee colonies with Varroa mites forces us to look for new or well-forgotten old methods of dealing with them. But no fight is possible if you don't know your opponent well. In the course of theoretical research and practical experiments for over four years, we managed to understand the peculiarities of development of Varroa mites population in honey bee colonies, to create a method for controlling the development of the mite population and to outline additional ways to combat this parasite which destroy a huge number of bees around the world. For monitoring of the development of Varroa mites population we developed our own method on the basis of counting of Varroa mites falling free of on a sticky board. This method is based on the monitoring of two different types of falling mites - old females and young female mites that did not take part in the reproduction. This made it possible not only to understand the main cycles of reproduction of Varroa mites in bee colonies, but also to propose simple and absolutely harmless zootechnical methods for suppressing their development, such as cold wintering, suppression of the swarming state, removal of the earliest and latest sealed brood of worker bees. And all this with a precise understanding of those key points when each of these impacts will be most effective.
Key
words
Introduction
Studying the materials published in the American Bee Journal # 4 2020, we came across statistics, which fully correspond to our own results obtained during the work on the Apivox Varroa Eliminator project. This both pleased and upset us, since the loss of bees wherever they occur, worsens the situation with the bees on the entire Earth.
In addition, the statistics again confirmed, that none of the drugs currently used in beekeeping, no matter how loudly they are advertised, do not radically solve the problem of combating varroatosis in our apiaries, but only put us "on the needle" of companies that produce heaps of "highly effective drugs" for the treatment of bees from various diseases!
Let's move on to specific data and their interpretation ...
So, the first material is data on the loss of
bees over the past 10 years according to Bee Informed organization (Fig1).
The graph
shows, that in the
The graph
shows, that in the
Professionals also have bee losses, but they are significantly less than those of amateurs and beekeepers with small apiaries (Fig2, Fig3). We also agree with this. The reason, as a rule, is that amateurs are trying to conduct eco-friendly beekeeping and to use as little as possible chemicals intended to treat bees from various diseases. At a minimum, they use them in the event of illness of their bees.
Professional beekeepers are always trying to act ahead of the curve, as are poultry and livestock breeders. Why wait for the animals to get sick? This always results in waste of time and money. All measures for the treatment or, more precisely, for the prevention of diseases are carried out within clearly defined terms, regardless of the presence or absence of a real disease. Therefore, diseases occur less frequently and the losses from them are less. If the main task of the apiary is pollination or rearing queens, then the amount of chemicals in the combs and honey does not matter at all for them.
But, as it
can be seen from the graphs, the losses of bees both in professional beekeepers
and in other beekeepers, have been growing in recent years proportionally
despite some difference in absolute values !!!!
In addition to these data, there is a table, which became the result of a survey of beekeepers about the reasons for the death of bees in their apiaries. The result was expected - most of the bees died from infestation with the Varroa mites! I think that the column "weak in fall" can be safely summed up with the column "died from the Varroa mites" ... Our studies, which we told you about, claim, that this is most likely the result of an autumn peak in the development of the population of Varroa mites, which many beekeepers do not notice during and after Main honey harvest. So, we believe that 69% of the deaths of the bees in small apiaries occurs from infestation with Varroa mites, which today cannot be completely destroyed by any means! What does all this say... It says that despite the advertising-oriented results of "successful use" of various oils and chemicals, they are not very effective in real life! To quote from an American Bee Journal article ... " Four chemical control options show the greatest potential for better survival in survey results for the past four seasons. Essential oils Apiguard and ApiLifeVar show about a 30% greater survival, and use of Apivar about a 29% better survival. Oxalic acid vaporization demonstrated an 11% better survival over the past three years, but survival improvement of Oxalic acid drizzle was minor and in only one of the last three seasons…" But, if we look at Fig. 1, we will see that there is absence not only of increase in survival, but, on the contrary, from year to year there is an increase in the death of bees.
That is why
we believe that it is important to understand the vital processes in Varroa
mites going on in bee colonies, to be able to control them and be able to
suppress this development not only with chemical preparations, but also with
simple zootechnical means that you need to know and be able to apply. Ideally,
we believe that it is necessary to achieve such coexistence of bees and Varroa
mites, in which their presence in bee colonies will cease to be lethal for the
latter.
Materials and methods
There are several methods for obtaining data on
the infestation of a colony of bees, of which the most radical is an alcohol
wash, and the most gentle is the control of the mites drop on a sticky board.
There were a lot of attempts in order to adapt a mites drop for analyzing the
degree of infestation of bee colonies, but everyone wanted to get specific
numerical data, even if this required adjusting the numbers to the result. On
the basis of this method, there were built some methods which were distributed
by the ministries of agriculture of the
Based on the average number of mites falling on sticky board per day, it is proposed to build a method for treating bees with acaricidal preparations. Representatives of the agricultural industry, trusting scientists, recommend this method for assessing the infestation of bee colonies as the least laborious. It is believed that it gives fairly accurate results. But sometimes it's not quite like that, and sometimes it's not like that at all. In various scientific works of scientists who studied and evaluated the accuracy of all known methods for calculating infestation, it is written that all methods are equally inaccurate at the very beginning , when the number of mites in the family is small, and at the end of the season, and that in these works scientists use at least three different coefficients for converting the number of daily falling mites to the total number of mites exists in the bee colony. We know that there is a coefficient by which the average daily tick talus is multiplied equal to:
1)
2) 120 throughout the season. Fig.7 (Development of the mite, Varroa jacobsoni oud., in the honeybee, Apis mellifera L., in Michigan, USA, and a comparison of diagnostic methods for detection of the mites Ahmad Al Ghamdi and Roger Hoopingarner )
3) 170-200 throughout the season. Fig.8 (GUÍA TÉCNICA PARA PARA LA LUCHA Y CONTROL DE LA VARROOSIS Y USO RESPONSABLE DE MEDICAMENTOS VETERINARIOS CONTRA LA VARROA DIRECCIÓN GENERAL DE SANIDAD DE LA PRODUCCIÓN AGRARIA SUBDIRECCIÓN GENERAL DE SANIDAD E HIGIENE ANIMAL Y TRAZABILIDAD)
This
already suggests that each researcher adjusted the coefficient to the situation
in his apiary, or in his zone. And even
this fitting does not work if used in
mathematical models, which are compared then, with the real results of counting
of Varroa mites in bees... Fig.9 (Population growth of Varroa destructor
(Acari: Varroidae) in honey bee colonies is affected by the number of foragers
with mites Gloria DeGrandi-Hoffman
Fabiana Ahumada Victor Zazueta Mona Chambers Geoffrey Hidalgo Emily Watkins deJong)
For our
project we invented our own method of calculating mites drop. It consists in a
separate count of dark - old, already participated in reproduction females, and
pale-colored young female mites and deutonymphs, which died or were not
fertilized by a male mite inside the cells, and were thrown out by the bees. Fig.10. We call this the two-graph method. So, what
is its meaning ...
The point is that in addition to the fall of old dark mites, that is clearly visible to everyone, there is another process - the process of death of young females that have not yet participated in the growth of the mite's population. Pay attention to the photo Fig.10. It shows the mites, which fell down on sticky board of our experimental hive in different seasons of the year. They all have a different color !!! Mature old fertilized females are deep red and burgundy! Young females have a bright red color that is darker or lighter depending on maturity, and the paler ones are not mature females and transparent individuals are deutonymphs ...
So, the method of two graphs that we use involves separate accounting of old female mites - the blue graph, dying during or after breeding, and young females that did not participate in reproduction - the red graph. By shifting back the blue graph of the fall of mature dark mites by 2.5-3 months, or the approximate life span of the mites, we can talk about the approximate time of their birth, and we can analyze the events that led to their appearance in the bee colony. The appearance of fall of pale mites, according to our long-term observations, is a very bad sign, and indicates an over-intensive reproduction of Varroa mites, when it uses for reproduction all the brood zones that are not even very suitable for reproduction in terms of climatic parameters. Thus, using two graphs (Fig. 11), we can learn about the past of the mites population from the blue graph, about the prospects for its increase in the future, and about the intensity of its growth process at the moment according to the red graph.
In general, the mites drop by itself at the time of control is not always indicative. There are intervals, as we can see from the graphs, when there is practically no fall of the mites or it is very small. This does not mean that there are no mites or that its number is small. It's just that the mites are waiting for the right conditions for mass reproduction, or they're just all young and healthy. From the graphs, we see that the mass death of Varroa mites of all ages is directly related to the cycles of enhanced reproduction, which, apparently, takes away the last strength from old individuals and leads them to death in the cells. In this case, the idea that the mites live for about 2-3 months and the method of shifting the schedule of mites drop for 2-3 months back shows the time of their birth, allowing you to see the real time of birth of this mass of falling mites. And these are the months when the most active reproduction of bees takes place, and when it seemed to us that there were almost no mites in the family (Fig. 11).
Analysis
of graphs of mites drop obtained by us for 4 years of continuous observations
of six families of bees showed that by studying of free fall of Varroa mites on
a sticky board, one can observe the development of the mites population and make
predictions about its changes. But, it must be taken into account that the drop
of mature mites informs us about what happened in the bee family 2-3 months
ago, and makes it possible, although not quite easy, to predict the number of
mites at the moment and in the future. This is possible because we know that in
average the mites population doubles in a month. The appearance of a drop of
pale-colored young mites tells us about a sharp increase in growth of Varroa
mites population and an emergency situation in the bee colony. Observing this
process can allow beekeepers to urgently take the necessary measures to protect
the bees from death.
Results
1) Observations show on the example of all families, that each next burst of the mite's reproduction is at least 2-3 times stronger than the previous one. This difference roughly corresponds to the amount of mature mites fallen free during the present reproductive cycle, divided by the amount of fallen free immature mites of the previous reproductive cycle... The value is approximate, but it is confirmed in all experimental families. You can see it on the graph.
2) Observations show that swarming state of bees should be avoided by all means. It is the massive laying of drone and bee brood before swarming and, most importantly, its thorough heating by the bees, that leads to a catastrophic increase in the mite's population due to a multiple increase in the reproductive territory, comfortable for it.
3) Observations show that if, during the next cycle of enhanced reproduction, free fall of an immature mites significantly exceeds free fall of an old mature dark mites, and has sufficiently large values, then this is a very alarming signal. It can be assumed, that not only a large number of young mites were released, but the founding females did not die ! Thanks to this, it accumulates the mass of live mites, ready to participate in the new reproductive cycle, and exactly this makes the next flash of reproduction so powerful.
During the main honey flow period, when the mites have less bee's brood in the nest for reproduction and in the mites population, remains only young viable individuals, mostly not yet ready to die and fall down on sticky board, free fall of the mites sharply reduces or stops altogether ... With a decrease in the flow of honey at the end of the main honey harvest, as well as with removal of honey by beekeepers at the end of summer, the volume of free space for laying eggs by the queen increases ... The weather conditions at this time, in August-September, are still favorable for the bee's brood rearing and for the mite's reproduction. At this time, beekeepers are trying to get as many young bees as possible, because exactly these bees will winter and form a family next year. Under these conditions, starts new powerful laying of brood by the mites, which leads to the powerful autumn splash in the growth of Varroa mites population. This process is accompanied by a strong fall of both - old mites born in spring , and immature young underdeveloped individuals that die in the process of reproduction.
4)
Observations show that the state of a bee colony when a quantity of falling
mature mites reaches quantity up to 5 mites per day, in principle, is not too
bad for a colony of bees of almost any strength. The bees of a strong family
can even withstand a situation, when a quantity of falling mature mites reaches
60-70 mites per day, for up to a month.
They are also can withstand a situation when a quantity of falling
mature mites reaches from 20 to 40 ticks per day, for 2-3 months. Of course, in
the bee's family appear many damaged bees that are unable to fly, and this
weakens the family and reduces its honey productivity... We can see such a
situation in the graphs of three families of our experimental apiary - 5-1,
5-2, 8-1. At the same time, 8-1 and 5-1 produced about
Discussion
So, thanks to our method of two graphs and based on the results of the control of the mites drop in 6 families for 4 years, we can state that in the life of Varroa mites there are three main peaks of reproduction activity with intervals of greater or lesser decline in reproductive activity between them (Fig. 12 ).
The first peak - is the winter breeding peak. The time of this peak is January, February and March. It is at this time that mountain breeds of bees such as Carnica bees and
The death of the mites of this breeding cycle occurs in March, April, May, and is also accompanied by the death of old females, which wintered together with the bees, and gave life to this generation of the mites. When the winter reproductive peak is insignificant, free fall of old hibernated female mites is the main part of the mites drop and it tends to stop around mid-May, which can create the illusion that the bee colony is mites-free, if you decision will be based on the size of the mites drop.
The second peak of reproductive activity falls on pre-swarming time - that is, mainly on April, May and June. Undoubtedly, the basis of the danger of this peak is laid precisely in April, when the first mass brood of bees appears and the mites born during the winter peak, and the mites still remaining after wintering, can enter the brood en masse for reproduction. Subsequently, the conditions in a colony of bees preparing for swarming allow the mites to maximize their population in May and June.
The death of the mites of this breeding cycle and their fall on sticky board occurs in the second half of July, August and September. It was at this time that scientists and beekeepers registered the maximal fall of Varroa mites on a sticky board and based on this, talked about the mites population growth ... But this is not entirely true ... It's just that the massive death and fall of the mites of spring breeding cycle coincides with the third reproductive cycle of Varroa mites reproduction - post-honey harvest peak! Thus, the mites drop tells us about the both - about the death of old mites and about the birth of new ones. We will tell you how this happens a bit later.
The third peak of reproductive activity of Varroa mites falls on the time after honey harvest, when the number of bee brood available for reproduction increases again. In the interval between the second and third peaks, occurs a period of latent reproduction of the mites. The reason for this is the youth of most mites and the absence of a large number of old females for which it is time to die and to fall down on sticky board. At this time, it may also seem that there are almost no mites in the bee colony. This makes the British and American Beekeepers' Association's recommendations for mite control on the basis of counting the number of Varroa mites that fall on a sticky board per day, meaningless. Exactly at this time the mites drop is minimal for natural reasons, and does not say anything about the total number of mites in the bee colony.
The
death and fall on sticky board of the mites born during this peak, as well as
those born in the fall, occurs more or less evenly and usually continues
throughout the winter and spring. As we said, the mites born in late summer and
autumn can survive until the first half of May.
Speaking about the peaks of reproductive activity, one must not forget that between them the mites also reproduce more or less actively and the peaks appear against the fond of some background values. Naturally, such background values are also present in the mites drop.
Understanding the main peaks in the development of Varroa mites population leads us to the understanding that in order to radically reduce the infestation of bee colonies, it is necessary first of all to suppress these peaks in the development of the mites, and especially the winter and spring ones.
So, having come to an understanding of the construction of the life cycle of Varroa mites, it can be argued that the application of a set of rules for keeping bees during the year, which allow reducing colony infestation in a natural way, will provide significant assistance in solving the problem of preserving bees and suppressing the development of Varroa mites in their colonies. What methods can be used for this instead of those, or in addition to those that beekeepers usually use...
Let's consider these methods in chronological order in accordance with
the life of bees ...
Wintering: The first step in keeping bees properly in terms of Varroa mites control - is cold wintering.
There is one very interesting result, as it were, hidden in the diagram obtained by Bee Informed and related to our previous statement about the death of bee colonies in small apiaries from varroatosis, even when beekeepers do not notice it. Pay attention to the diagram Fig.13! What do the two seasons 2014-15 and 2019-20 have in common? In common they have the fact that in both cases more bees died in summer than in winter! These years have been extremely warm and with extremely warm winters. With temperatures 5-6 degrees on average above the climatic norm!
What does this mean? It means, that in winter the mites were able to freely breed several new generations in the winter brood of bees, and to increase its population 4-8 times compared to normal years when winters were cold, using February and March and possibly January for breeding!
It
is this possibility that should be eliminated. It is this event that will help to lay the
foundation for the fight against Varroa mites during beekeeping season. Exactly
cold wintering should prevent rearing of winter brood, which is not able to
significantly improve the state of bee family,
but is able to become a "farm" for growing Varroa mites.
Finally, exactly this event will help to avoid the first spring peak in the
growth of the mite's population.
Spring development till the main honey flow: The main methods of influencing the mites population in this period are: the reduction of the space suitable for the reproduction of the mites and the deterioration of the conditions required for their reproduction. Several techniques can be involved here together or separately ...
1) Creation and maintenance of young families. Creating young families in the apiary to replace old working families by forming artificial swarms, by forming offshoots with mature queen cells, the beekeeper "kills two birds with one stone at once." Firstly - when creating such families, the brood which at this time is the main repository of the mites, is not used or is used minimally. Secondly - such colonies are easy to process in any way, including using of organic acids, which is a method, that minimally contaminates frames and honey. Thirdly - the families will have young queens, which is an excellent anti-swarming technique. Such families, as a rule, have a good start in development and begin wintering healthy and clean.
2) Suppression of swarming state of the bees in order to deprive the mites possibility of super-active reproduction in a huge amount of well-heated brood of worker bees and drones. Before the start of the main honey collection, possible methods are: the presence of young queens, expansion of the nest, removal of maximum possible amount of drone brood. Firstly, as we have already said, colonies with young queens are, in principle, much less prone to swarming. Secondly, the expansion of the nest reduces swarming mood of worker bees and deprives mites of a large, well-heated brood zone and, most importantly, a well-heated drone brood. Thirdly, the use of building frames allows not only to reduce swarming mood of the bees, but also to remove from the hive and destroy almost ninety percent of drone brood with mites in it, with a minimum expenditure of efforts and without injuring the bee family.
3) Removal of sealed brood. Removal of frames with sealed brood, which can be carried out during the period of spring growth of bee's families in order to prevent swarming and to create offshoots, significantly contributes to the fact, that the disease does not take on a threatening character in the main colonies until autumn, even in the absence of other mites control measures. In addition, holding such an event in June can, under certain conditions, increase honey productivity of bee's families by reducing number of bees engaged in brood rearing. At the same time, the families from which the brood was removed, can be treated with organic acids, and this treatment will be very effective at this stage.
In the process of honey collection, it is possible to influence the mites population using method of of limiting oviposition of the queen. The use of this method will radically reduce the number of mites in the bee colony, by reducing the opportunities for their reproduction.
4) Autumn
preparation of bee families for wintering. It is possible that you can
again use the method of removing the sealed brood, and then proceed to
cooling the nest, in order to stimulate the end of brood rearing season.
The autumn removal of last sealed brood
will be useful if in the summer, after honey collection, it was not possible to
do this due to the large amount of brood in the bee colony. After the young
bees will come out of brood cells in the family in which all sealed brood was collected, they can be treated with natural acids
against the mites, and after this, the bees can be returned to their families
using one of the methods of conjunction of the bees. This will allow both to
clear the colonies from the mites, and to preserve their strength for
wintering. At the same time, cooling the nest in the fall will help stop brood
rearing, which is an incubator for the mites.
Conclusion
A study of scientific articles and printed materials, as well as our own researches, have shown that using only chemicals, it is impossible to defeat Varroa mites. When the effectiveness of acaricidal preparations is less than 100%, surviving mites constantly remain, and the overall resistance of Varroa mites to acaricidal preparations is constantly increasing. Today, it is already recommended to use 2-3 acaricidal preparations simultaneously or in turn to treat bees. Nevertheless, the results are deplorable. The rapid development of apiaries producing queens, and most importantly, bee packages, and massive selling them to beekeepers in spring, speaks of the constant death of bees in huge quantities.
It
is not possible to continuously increase the chemical load on the bees, getting
worse results from year to year. It is time to draw attention of beekeepers,
and first of all, beekeepers who have relatively few bee colonies, to
zootechnical methods of combating Varroa mites. All the rules listed here are not
a serious burden for such beekeepers. Some of them have been carried out
before, but some rules do not seem natural and you need to get used to them and
try them out in practice. Then they, like any new business, after a while will
also become natural and familiar, and most importantly, they will increase the
effectiveness of the fight against Varroa mites.
Literature
We used diagrams and a picture from the works :
1.
Population model for the ectoparasitic mite
Varroa jacobsoni in honey bee (Apis mellifera) colonies Stephen Martin National Bee Unit, Central Science
Laboratory, Sand Hutton,
2.
Development of the mite, Varroa jacobsoni oud.,
in the honeybee, Apis mellifera L., in Michigan, USA, and a comparison of
diagnostic methods for detection of the mites Ahmad Al Ghamdi and Roger
Hoopingarner
3.
GUÍA TÉCNICA PARA PARA LA LUCHA Y
CONTROL DE LA VARROOSIS Y USO RESPONSABLE DE MEDICAMENTOS VETERINARIOS CONTRA
LA VARROA DIRECCIÓN GENERAL DE SANIDAD
DE LA PRODUCCIÓN AGRARIA SUBDIRECCIÓN
GENERAL DE SANIDAD E HIGIENE ANIMAL Y TRAZABILIDAD
4.
Population growth of Varroa destructor (Acari:
Varroidae) in honey bee colonies is affected by the number of foragers with
mites Gloria DeGrandi-Hoffman Fabiana
Ahumada Victor Zazueta Mona Chambers
Geoffrey Hidalgo Emily Watkins deJong
5.
A deadly honey bee parasite, the Varroa
mite. PUBLISHED BY Bayer AG
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