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Auvergne: study of the annual biological cycle (CBA) of the local black bee in 1999-2000
MALLET, N; CHARLES, L LPA of Combrailles, Street Montaigne 63380 in Pontaumur (France)
Introduction
The anarchistic importation of swarms and queens of foreign races remains a current practice in the majority of the French areas. On the ground, the coupling of the queens of bees not being controlled, the breeding, the multiplication and the diffusion of these introduced stocks generate genetic disorders which put in danger the indigenous bee, at the natural state, in many sectors. In Puy de Dôme, the ecotype "black bee local" was the subject of a study of population led by the agricultural college of Pontaumur in 1990-1991.
The biometric results obtained made it possible to specify the principal discriminatory and measurable morphological characters of the black bee. From the enzymatic study, the rate of hybridization of the populations of bees in various zones of the department could be estimated.
Extremely of this lesson, and before engaging an important programme of conservation and multiplication of the identified pure stocks, it seemed essential to us to study the adaptation of the indigenous bee to its environment. This work completed in 1999-2000 specifies the factors which condition the development of the colony, and makes it possible to characterize its annual biological cycle (CBA).
Method of analysis
Support of study
Taking into account the work generated by many measurements of the various criteria selected, only one colony was followed during the year 1999. The queen born in 1998 comes from stocks of black bees controlled biométriquement since 1993.
Choice of the site
The frequency of handling, and the need for having a power supply near the hive (meter of bees) justified its installation in the enclosure of the establishment. The whole of measurements as well as the weather statements were thus carried out on the spot. The calendar of flowerings was established, as for him, starting from observations carried out in a ray of ten kilometers around Pontaumur.
Characteristics of the zone of study
• Zone of half mountain on the plate of Combrailles in the varying North-West of the Central Solid mass with an altitude from 550 to 750 meters.
• Mountain semi climate with oceanic, rather hard and rainy tendency in particular in winter period.
• Landscape very of the woodlands composed of small pieces surrounded of quickset hedges and a vegetable cover directed primarily towards the production of grass (the meadows occupy between 70 and 80 % of the SAU). However, wood and forests (mainly Douglas, Spruces, Oaks and Beeches) cover approximately 30 % of the total surface of the territory.
Measuring criteria
1 - Calendar of flowerings
The readings taken at each beginning of flowering, aim to study the correlations between the development of the colony and the presence to a given moment of potential sources of pollen or nectar.
2 - Weather statements
Carried out daily towards 8. 00 of the morning, they concern:
- The minimal temperature and the maximum temperature (expressed in degrees Celsius) recorded under weather station shelter;
- The height of precipitations (water and snow) expressed in mm.
3 - The exits bees
These readings were taken daily thanks to a meter of bees. This one, is composed:
- of a module of recording of information (metal bar comprising 12 electric eyes),
- of a module of posting of information (screen with digital posting). The module of recording is placed at the top of the board of take-off of the hive (it is the only exit making it possible the bees to leave or enter the hive).
The cells record all the passages of bees when those cross the threshold of the hive. The meter does not make however the difference between the entries and the exits. It is thus necessary to divide by two the result of counting to know the number of flights accomplished daily by the bees. We use in the study the term of "exits bees".
4 - The surface of the couvain
These readings were monthly taken (except for August and June when two readings were taken) for the "working life" of the colony (from March to August). They make it possible to measure the evolution of the laying of the queen, who conditions the development of the colony.
The couvain presenting an elliptic form, the formula retained for the calculation of its surface in dm2 is: (R X R) X 3,14 where R is the small ray of the ellipse and R the large ray.
5 - The weight of hive
Statement monthly during the year, it makes it possible to evaluate the quantities of honey consumed and produced by the bees.
Some precise details concerning the terms used:
- the "weight of the body of hive" = weight of the plate + weight of the body (without the roof) + weight of the empty built executives.
- The weights and profits of honey weights expressed in this study include actually honey, pollen, the couvain and the bees. Indeed, these various elements prove to be indissociable during the weighing.
6 - Pollinic analysis of honey
We made carry out by the AFSSA (French Association of Medical Safety of Food) an analysis of 2 honey samples corresponding to 2 harvests of the year (June and August).
With through the identification and the enumeration of various pollens, these two analyses make it possible to specify the floral origin of collected honeies. They are supplemented by examinations physicochemical and organoleptic which can characterize the preponderance of some miellées.
Presentation and interpretation of the results
I - Activity of the colony and meteorology
Total analysis
6 843 128 : it is the number of exits bees noted over the year.
108 710 : it is the number of maximum exits recorded over one day: July 2, 1999. Conditions weather: Maximum T° 36°, mini T° 7°, no pluviometry, temperatures increasing over the 6 previous days, period of rain from the 25 to June 30.
15 days in the year during which the meter does not record any exit.
149 days in the year during which the meter records less than 1000 exits.
18 days in the year during which the meter records more than 80000 exits.
8°C, it is the temperature with the lower part of which the activity is null or almost null except some exceptions: March 5, T° = 7° left = 1023 and on February 21, T° = 8° left = 2222
69 days in the year when the number of the exits lies between 1 and 50
65 days in the year when the number of the exits lies between 50 and 1000
52 days in the year when the number of the exits lies between 1000 and 5000
57 days in the year when the number of the exits lies between 5000 and 2000047 days in the year when the number of the exits lies between 20000 and 50000
43 days in the year when the number of the exits lies between 50000 and 80000
Tendencies
• The activity of the colony is closely related to the progression of the maximum temperature: if the temperature is increasing over several days, the exits of bees follow this tendency (and vice versa) Ex. : from the 22 to May 31, the 8 to June 12.
• The temperatures recorded during the night (minimum) seem to reinforce or on the contrary to inflect the tendency induced by the maximum temperature : if the maximum temperature and the minimal temperature are increasing, then the activity will be more important than if the maximum temperature is increasing and the decreasing minimal temperature.
• One notes an increase (higher than the previous period), immediate and temporary of the exits after one period of rain of several days. This is particularly true in full summer. Ex. : July 2, July 29. Indeed, one can think that an abundant rain at this period of the year supports a production of nectar on the level of the flowers, which is immediately made profitable by the bees.
• One observes distinctly on the curves of activity the various periods of the biological cycle of the colony : recovery, full activity, regression and wintering. These periods are below detailed.
Periods of the cycle
O Recovery : MARCH-APRIL, characterized by
- an increasing but very irregular activity because related to the weather conditions. It is at this period that the correlation between maximum T° and the exits of bees is most important,
- an average of 14000 sorties/jour over this period (12,5 % of the annual exits).
Activity of flight and weather of March 1999
Activity of flight and weather of April 1999
O Full activity : of at the beginning of MAY at JULY 15, characterized by
- an activity less irregular than previously. A less important correlation between T° and the number of exits because the level of the temperatures is higher than the previous period,
- an increasing progression of the activity,
- a strong activity even days of rain (downpours),
- one period very favorable this year there of May 22 to June 1 bus :
- preceded one period of rain
- associated a regular increase of the temperatures : of 16° with 33°C.
- no precipitation during this period
- regular progression of the exits of bees, 57000 with 100000/jour over this period.
- an average of 65000 sorties/jour over this period (72 % of the annual exits) with peaks of 100 000 sorties/jour (100000 June the 1 and 2, 108000 on July 2) and low points from 15000 to 20000 sorties/jour (May 17, June 5, July 4).
Activity of flight and weather of May 1999
Activity of flight and weather of June 1999
Activity of flight and weather of July 1999
O Regression : from JULY 15 until the end of SEPTEMBER characterized by
- a regular reduction in the number of exits, 50000 to July 15 with 10000 at the end of August and 5000 at the end of September,
- an average of 13300 sorties/jour over this period (14,8 % of the annual exits). Activity comparable with that of the period of recovery in term of exits of bees.
Activity of flight and weather of August 1999
Activity of flight and weather of September 1999
O Wintering : of at the beginning of OCTOBER with at the end of FEBRUARY characterized by
- a number of exits almost no one. The activity recorded over October (at one time when the sources of nectar, pollen or propolis are non-existent or negligible) is related to beautiful days of autumn during which the bees evolve/move on the board of flight without real activity of butinage or collecting of pollen,
- some exits of cleaning if sunny day and T° higher than 10°C ex. : November 27, January 5,
- an average of 373 sorties/jour over this period (0,70 % of the annual exits).
Activity of flight and weather of October 1999
Activity of flight and weather of November 1999
Activity of flight and weather of December 1999
Activity of flight and weather of January 2000
Activity of flight and weather of February 2000
II Development of the couvain and associated flowerings
• Resumption of laying: it is noted at the beginning of March thanks to the contribution of pollen of hazel tree, then continues all April thanks to the pollen of willow and the beginning of flowering of the fruit trees. However the precocity of the flowering of the hazel tree much earlier involves sometimes a resumption of laying (January or February if the temperatures are lenient). This one does not present much interest for the colony, because it appears in the majority of the nonviable case: indeed, at this period of the year the workers cannot maintain the temperature necessary to the development of the couvain. During this period (April March-30 1) the surface of the couvain is almost multiplied by 3 in two months : one passes from 16 dm2 on March 3 to 45 dm2 to April 24.
Curve of evolution of the couvain and flowerings
• During the following period (May-30 1 May), the tendency is accentuated, the abundance of the potential sources of pollen (mainly fruit trees and the dandelion) makes it possible to multiply in only one month the surface of the couvain by 2 : one passes from 45 dm2 on April 24 to 86 dm2 on May 19. However, it is necessary to underline the random aspect of this period during which this basket is exploited only if the weather conditions allow it. In the contrary case, it is not rare to note important pollinic deficiencies at that time of the year.
• At the beginning of June, the curve marks a slope much weaker than previously very continuously to progress slightly until the 6 where it reaches its maximum : 89 Dm2. Taken measurement on June 19 reveals a considerable reduction, but nevertheless one notes that the period being spread out of May 19 at June 19 corresponds to the most stable phase of the surface of the couvain, that Ci undergoing during this period only weak variations (about 4 Dm2).
• Regular fall of the surface of the couvain over the period of June 19 at August 8 (-30 Dm2 of June 19 at July 11, -35 Dm2 of July 11 at August 8). It should be noted that large re-entries of pollen of summer related to the flowering of the plants of meadows (leguminous) and of waste lands (brambles, thistles) have only one limited interest, because they arrive at one period when the couvain is in strong regression. Not consumed stocks are likely to mildew during the winter and will not be of any utility to the colony for the period of recovery. Nevertheless, one can think that the harvest of this pollen will support the breeding of larvae and by consequence the presence in a number, of bees of winter which will contribute to better begun again spring.
III - annual Activity by fortnight
One finds on this graph the various periods indicated higher. It highlights the large volume of exits recorded of at the beginning of May at semi July, which represents more of the 2/3 of the annual activity; the other 1/3 being spread out mainly over the periods of recovery and regression (4 months 1/2). To note the period of wintering which is spread out over 5 months, and during which the activity proportionally null, is compared with that of May-June.
Exits of bees per fifteen days period
One notices the speed with which the colony develops its activity between the second fortnight of April and at the beginning of May (one passes from 357 000 exits at the end of April to 880 000 exits on the first fortnight of May) and the absence of period of transition.On can make the same remark with regard to the fall of its activity between the first and the second fortnight of July (of 880 000 at the beginning of July with 450 000 at the end of July).
1106025 it is the maximum of exits recorded on a fortnight (from the 15 to May 31).
770 it is the minimum of exits recorded on a fortnight (of 1st at December 15).
IV - Decomposition of the weight of hive
Some precise details concerning the concepts of "weight of hive" and "honey weight" :
- the "weight of hive" is consisted of the weight of body of hive (18,5 kg), of the "honey weight" present in the hive at the moment of the weighing, of the weight of the rises (6,1 kg each one) and of the weight of harvests (June and August).
- the "honey weight" does not include/understand only the quantity of honey stored in the body and the rises, but also those of pollen, the couvain as well as the weight of the bees presents in the hive at the moment of the weighing.
Evolution of the weight of the hives (1)
Evolution of the weight of the hives (2)
Weight of wintering
Before the period of wintering, one estimates that a hive must weigh around 31-32 kg (including 15 kg of honey) not to risk food shortage. It is noted that the hive of study is located perfectly in this fork, and even a little with the top if one takes October as reference (15,5 kg of honey in the corps).Les reserves present in the hive in February 2000 are more important than those of the same month the previous year (11,5 kg in February 2000 against 9,3 kg in 1999). One can explain this difference is by a larger quantity stored in 1999 than in 1998, that is to say by a more reduced consumption over the winter 2000-2001.
Pose rises and harvests
The installation of a rise at the end of April is justified fully for two reasons :
- important Increase in the honey weight recorded over the following period
- important Increase in the surface of the couvain over the following period which can involve a swarming or a blocking of laying for lack of place in the body of hive.
The installation of the second rise at the end of May falls at point to accomodate the important quantity of honey (14,7 kg) stored by the bees during the following period. The surface of the couvain reaching at this period its maximum, storage inside the body becomes impossible then.
15,5 kg it is the honey weight remaining in the body in October
10,6 kg it is the quantity of honey collected in the rise in June
11,9 kg it is the quantity of honey collected in the rise in August
This figure of harvest (22,5 kg on the whole) can be regarded as slightly higher than what one can wait of an average hive for one year "normal", knowing that no nourrissement speculative was carried out on this colony led as a sedentary. Cete colony corresponds well to the profile of the local black bee, which while ensuring of the sufficient reserves of wintering, produces an interesting harvest all the same.
Pollinic analysis of the honey of spring
Pollinic analysis of the honey of summer
Honey Production/consommation
The pay production/consommation of honey becomes positive as from April with the flowering of the fruit trees; their pollens are present in the pollinic analysis of the first harvest. It "explodes" then during June and May, and stagnates over the period July-August. From September, the bees start, and this for all the winter period, to consume more honey than they do not produce any.
However:
- It is undoubtedly necessary to relativize the profit of honey weight recorded over the period of April 24 at May 19 (+ 12,4 kg between the two weighings), because during this same lapse of time, the surface of couvain almost doubled, generating a considerable profit of weight. This increase in weight is thus not ascribable with the only contributions of nectar in the hive.
- A contrario, the weak profit of weight noted between June 19 and August 8 (+ 2,8 kg on the whole) is without any doubt clearly under estimated. Indeed during the same time, the surface of the couvain is divided by 4, it appears obvious then, that the honey weight stored in the cells, which contained couvain up to now, came to replace the weight of this last. This assumption is corroborated by the presence in the harvest of August of clover pollen in large quantity and whose potential nectarifère is expressed really only as from June 15-20. The significant number of exits of bees recorded during this period (2 195 850) comes to confirm this assumption.
- the profit of weight recorded of May 19 at June 19 (+ 14,7 kg of honey in the hive) is as for him nearer to reality than the precedents since between two measurements the surface of the couvain almost did not change : 86,14 Dm2 on May 19 against 85,03 Dm2 on June 19.
+ 12,4 kg, it is the profit of weight noted between 24 April and May 19 (left bees over the same period : 1 284 487) : 103 587/kg.
+ 14,7 kg, it is the profit of weight noted between 19 May and June 19 (left bees over the same period : 2 255 961) : 153 466/kg.
+ 2,8 kg, it is the profit of weight noted between 19 June and August 8 (left bees over the same period : 2 195 850) : 784 232/kg
V - Activity, couvain and production/consommation of honey
One notices the shift between the curve of activity and the surface of the couvain, which corresponds to the time passed between the development of the larvae and the adult exits of individuals for the butinage. This is particularly true between May 19, dates to which the surface of the couvain is almost with its maximum, and the explosion of the exits recorded over the posterior period with this measurement (of May 19 at June 19).
Activity - couvain - consumption honey
This shift is still perceptible in July-August when the curve of surface couvain falls before that of the exits of bees whose slope becomes less steep as from July 11. The strong variation precedent this date can be explained by the rather unfavourable weather conditions (10 days of rain) during this period.
In spite of this shift, the two curves follow same the tendencies: progression forces and falls violent. One records 5 months of positive balance, 7 months of negative balance.
32,1 kg, it is the honey weight gained from March 1999 to August 1999 (honey weight present in the body in August - honey weight present in the body in March + harvests of June and August)
9,2 kg, it is the quantity of honey "consumed" from September to March
Synthesis
One often reproaches the local bee for having a rather late starting, which confirms partly this study; however, the speed of its development enables him to concentrate its activity in spring period. It should be recalled that the weather conditions in Combrailles favour hardly an earlier recovery which would be likely to compromise the balance of the colony. The production of honey is very dependent on the climatic conditions which can be relatively different one year on the other. Vis-a-vis for its variations it should well be recognized that the local black bee is particularly well adapted, while making in kind be to the maximum of its potential between May 15 and July 15. This period is undoubtedly most favorable to the activity of the colony and most favourable with strong miellée. Nevertheless its development is nevertheless rather advanced at the end of April to be able to possibly profit from good weather conditions, as it was the case in 1999, in order to store a relatively large quantity of honey over the period end May April-beginning. The analysis would have gained in precision by multiplying the statements especially in period of full development. In addition, the quantification of the contributions of pollen and their identification would have made it possible to confirm the broad outline of the CBA and to specify the polliniferous potential of the listed vegetable species.
© MALLET & CHARLES, 2001 - All rights reserved