Journal of Apicultural Science 47 EFFECT OF AGE OF EGGS USED FOR REARING HONEY BEE QUEENS ON THE NUMBER OF RECEIVED QUEEN CELLS Jakub Gą bka, Maciej Ochnio, Zbigniew Kamiński, Beata Madras-Majewska Warsaw University of Life Sciences - SGGW Apiculture Division, Nowoursynowska 166, 02-787 Warsaw, Poland E-mail: jakub_gabka@sggw.pl Received 04 November 2010; Accepted 30 May 2011 S u m m a r y The age of the brood used for rearing queens has a major impact on the quality of the resulting queens. The best are queens reared from eggs. The aim of the experiment was to investigate whether the age of the eggs affects their acceptance by the rearing colonies. In four series, eggs at the age of 0-18, 24-42 and 48-66 hours were introduced to five colonies. All colonies in the first and third series had open brood and were 1 day without queens. The second and forth series had no open brood and were 10 days without queens. Out of all the 720 introduced eggs, the bees accepted 44.4% for queen rearing. No significant differences were detected between the total number of eggs accepted by the colonies with an open brood - one day after the queens had been removed (43.6%) and colonies without open brood - ten days after the queens had been removed (45.3%). However, significant differences were detected between the acceptance of eggs of different ages. The age of the eggs did not significantly influence their acceptance by rearing colonies with open brood - one day after the queens had been removed. However, the bees significantly accepted the lowest percentage of eggs (25%) after the youngest eggs, 0-18 h old were introduced, and the bees accepted the highest percentage of eggs (64.2%) after the oldest, 48-66 h old were introduced into colonies without open brood - ten days after queens removal. Keywords: honey bee, bee eggs, queen rearing, rearing colonies. INTRODUCTION The quality of honey bee queens depends primarily on the age of the brood used for queen rearing. The queen bee layingyield depends on the number of ovarioles and the volume of the spermatheca. Larvae used for rearing queens should be as young as possible. Queens with the highest weight, the highest number of ovarioles and the highest volume of the spermatheca are obtained by rearing from eggs (Jordan, 1960; Woyke, 1971). Chuda-Mickiewicz and Prabucki (1998) did not notice significant differences in bee queen quality when reared from the 3-day-old eggs and from 1-day old larvae. Weiss (1960) investigated the survival of eggs outside the hive in order to determine the most appropriate age of eggs to be transferred as breeding material. He stated that the best age to store eggs outside the colony is the age from 1.5 to 2.5 days. According to Ostrowska (1974), eggs used for rearing queens should be at the age of 2.5-3 days, and according to Pidek (1987) not older than 2 days. Örösi Pal (1964) created a method of rearing queens from eggs by grafting the eggs with the cut bottom boards of the cell. In the Jenter method (Jenter, 1983; Sieger, 1983) and also in EZI Queen Technology method (Wilde, 2002), it is possible to rear queens from eggs or from larvae without grafting them. Some authors (Ostrowska, 1974; Pidek, 1987) claim that unsealed brood should be present in a rearing colony, but according to Skowronek and Skubida (1988) the presence of open brood causes
48 weaker larvae feeding in queen cells and the best accepted larvae are those larvae introduced to colonies without brood. Gąbka et al. (2009) maintain that open brood in rearing colonies does not have a significant effect on the acceptance of eggs when the eggs are the age of 0-42 hours, but colonies without open brood accept eggs older than 48 hours significantly more than colonies with unsealed brood. Pidek (1987) stated that queen rearing colonies usually accept no more than 50% of the eggs. In the experiments of Gąbka et al. (2010), where Jenter frames were used, bees from rearing colonies with open brood accepted 54% of eggs at the age of 48-66 hours, and 72% of larvae which were the age of less than 18 hours and in colonies without open brood 72 and 90%, respectively. Chuda-Mickiewicz and Prabucki (1998) received the result of 56% of bee queens reared from larvae and 40% of bee queens reared from eggs. Winston (1987) reported that the age of the eggs can be specified by the angle of inclination to the cell bottoms. The more mature the eggs are, the more skewed. However, Woyke (1987) showed that change of egg position is not related to their age. Eggs are skewed due to the heating by the bee heads. When it is hot the egg stands, and when it is cold the egg lies. The aim of the experiment was to investigate whether the age of the eggs affects their acceptance in the rearing colonies. MATERIAL AND METHODS The experiments were conducted in the Apiculture Division of the Warsaw University of Life Sciences in 2010. There were 720 bee eggs originating from Carniolan queens that were introduced in four series, to five rearing colonies of Carniolan bees. Eggs were introduced on the 1., 10., 21. and 31. of July. Colonies covered from 14 to 16 combs. The Jenter method was applied, which enables rearing queens from eggs. The Jenter frame has removable cell bottoms which together with the eggs or larvae are placed in special tubes. This procedure makes the queen cell cups that can be introduced into rearing colonies. To obtain eggs of a certain age, the queen in another colony was isolated on the three Jenter frames for three consecutive days from 18:00 to 10:00 the next day. This way, eggs at the age of 0-18 hours, 24-42 hours and 48-66 hours were obtained after three days. Eggs were introduced to five rearing colonies, from which queens were removed one day before. To each colony, 36 eggs were introduced - 12 eggs from each age group. The number of built queen cells was checked three days later and the breeding frames were removed. The queen in another colony was isolated again for 3 days on Jenter frames to obtain eggs of different ages. When open brood was no longer in the rearing colonies, wild queen cells were cut off. Ten days after the queen had been removed, eggs were introduced to rearing colonies the same way as before. After three days, the number of built queen cells was checked. Breeding frames were removed from the colonies. Queens were introduced back to the colonies and after one week of laying eggs, the experiment was repeated. In the whole experiment, 240 eggs at the age of 0-18 hours, 24-42 hours and 48-66 hours were introduced. All colonies in the first and third series had open brood and in the second and fourth series had no open brood. One-Way and Two-Way ANOVA was applied. Duncan s test was used to detect statistically significant differences between groups. RESULTS Two-Way ANOVA revealed that the age of eggs (first factor) affected their acceptance (F 59,2,1 =6.223, P=0.004), but Two-Way ANOVA did not detect any significant effect of the presence of open brood in 1-day queenless colonies or absence of open brood in 10-day queenless ones (second factor) on egg acceptance (F 59,2,1 =0.102, P=0.751). Table 1 shows that out of all the 720 eggs introduced, the bees accepted 44.4%.
Journal of Apicultural Science 49 Age of eggs (hours) Acceptance of eggs of different ages in rearing colonies (all series) Number of introduced eggs Number of eggs inrtoduced to one colony in one series Min.-Max. Mean ± se % Table 1 0-18 240 12 0-10 4.05 ± 0.58 a* 33.7 24-42 240 12 0-10 5.20 ± 0.54 a 43.3 48-66 240 12 1-11 6.75 ± 0.57 b 56.2 Overall 720 36 0-11 5.33 ± 0.36 44.4 *Different letters indicate significant differences between the means. Fig. 1. The interaction between the open brood presence, the period of time without queens and the age of introduced eggs. The oldest eggs (48-66 h) were significantly better accepted (56.2%), than the younger ones (0-18 h and 24-42 h - 33.7% and 43.3%, respectively). The second double factor (brood and period of being queenless) could not be separated because every time eggs were introduced to rearing colonies - one day after queen removal, there was unsealed brood in the combs, but if eggs were introduced ten days after the queens had been removed - there was no open brood in the colonies. There was a significant interaction (F 59,2 =3.619, P=0.034) between the age of eggs and the double factor. The double factor is the presence of open brood and the period of time without a queen (Fig. 1). Two-Way ANOVA detected a significant effect of the age of eggs (first factor) on their acceptance (F 59,2,3 =5.805, P=0.006) but no significant effect of the different series (4) of egg introductions (second factor) on their acceptance was found (F 59,2,3 =0.330, P=0.803). Significant interaction between the age of eggs and different series of egg introductions was not found (F 59,6 =1.371, P=0.245). One-Way ANOVA revealed that the age of the eggs did not significantly affect their acceptance in rearing colonies with unsealed brood, one day without queens (F 29,2 =0.342, P=0.714). Out of all 360 eggs introduced to those colonies, the bees accepted 43.6% (Tab. 2). However, the age of the eggs significantly affected their acceptance in colonies without open brood, 10 days without queens, (F 29,2 =13.545, P<0.001). Out of all 360 eggs introduced to those colonies, the bees accepted 45.3% (Tab. 3). The youngest eggs (0-18 h) were accepted in the significantly lowest percent (25 %), and the oldest eggs (48-66 h) in the significantly highest percent (64.2%).
50 Age of eggs (hours) Table 2 Acceptance of eggs of different ages in rearing colonies with open brood - after 1 day without queens (first and third series) Number of introduced eggs Number of eggs inrtoduced to one colony in one series Min.-Max. Mean ± se % 0-18 120 12 1-10 5.10 ± 0.78* 42.5 24-42 120 12 0-10 4.80 ± 0.95 40.0 48-66 120 12 1-9 5.80 ± 0.89 48.3 Overall 360 36 0-10 5.23 ± 0.49 43.6 *Statistically significant differences between the means were not found. Age of eggs (hours) Table 3 Acceptance of eggs of different ages in rearing colonies without open brood - after 10 days without queens (second and fourth series) Number of introduced eggs Number of eggs inrtoduced to one colony in one series Min.-Max. Mean ± se % 0-18 120 12 0-8 3.00 ± 0.74 a* 25.0 24-42 120 12 2-7 5.60 ± 0.52 b 46.7 48-66 120 12 4-11 7.70 ± 0.63 c 64.2 Overall 360 36 0-11 5.43 ± 0.50 45.3 *Different letters indicate significant differences between the means. DISCUSSION Chuda-Mickiewicz and Prabucki (1998) received 40% of their queens, by rearing from 3-day old eggs. In this study, similar results were obtained in colonies with open brood where bees accepted 48.0% of the oldest eggs. The best accepted (64%) were the oldest eggs in colonies without open brood. This confirms earlier findings by Gąbka et al. (2009). The results are also consistent with the observations noted by Ostrowska (1974). Pidek (1987) believes that the eggs should not be older than 2 days, but in the presented experiment eggs older than 2 days were the best accepted. In experiments of Gąbka et al. (2010), bees in colonies without open brood accepted more eggs and larvae than in the colonies with open brood, but there were no statistically significant differences. According to Skowronek and Skubida (1988) the largest number of queen cells is received in colonies without brood. In this study, no significant differences were found between the total number of eggs accepted in the colonies with open brood and colonies without open brood. However, significant differences were detected between the acceptance of introduced eggs of different ages. The significant influence of the age of the eggs on the acceptance of eggs, was not detected in rearing colonies with open brood - one day after the queen had been removed. However, the bees accepted the youngest eggs significantly less, and the oldest eggs significantly more in colonies - ten days after the queens had been removed, when there was no open brood. On the basis of our research it cannot be stated whether the cause was a lack of open brood or a longer queenless period. To determine this, another experiment should be carried out. Probably, bees which are queenless longer attempt to shorten the time of rearing the new queens, by accepting older eggs. CONCLUSIONS 1. No significant effect was detected of different series of egg introductions on the total number of accepted eggs. 2. No significant effect was detected of the age of eggs on their acceptance in rearing colonies with unsealed brood - one day after queens removal.
Journal of Apicultural Science 51 3. The age of eggs introduced to rearing colonies, without open brood, ten days after the queens had been removed, significantly affects their acceptance. 4. The lowest percentage of eggs (25%) was accepted after the youngest eggs, 0-18h old were introduced, and the highest, (64%) after the oldest, 48-66 h old were introduced into colonies without open brood - ten days after the queen had been removed. REFERENCES Chuda-Mickiewicz B., Prabucki J. (1998) - The effect of rearing queens from eggs and larvae. Pszczeln. Zesz. Nauk., 42(2): 27-28. Gąbka J., Madras-Majewska B., Kamiński Z., Ochnio M., Hońko S. (2009) - The influence of open brood in rearing colonies on eggs acceptance in different egg age. Ann. Warsaw Univ. of Life Sc. - SGGW, Anim. Sci., 46: 59-62. Gąbka J., Kamiński Z., Madras- Majewska B. (2010) - The influence of development stage of brood used for rearing honeybee queens on the number of obtained queen cells. Roczniki Naukowe Polskiego Towarzystwa Zootechnicznego, 6(4): 241-245. Jenter K. (1983) - Eine neue Königinnen- Zuchtmethode aus dem Ei oder der Eilarve im Umsteckverfahren. Allgemeine Deutsche Imkerzeitung, 4: 101-103. Jordan R. (1960) - Die Zucht der Königin, ausgehend vom Ei. Bienenvater, 81(1): 3-7. Ostrowska W. (1974) - Gospodarka pasieczna. PWRiL. Warszawa. Örösi Pal Z. (1964) - Die Eierstöcke der Bienenkönigiennen nach ihrer Aufzuchtmethode. Deutsche Bienenwirtschaft, 15(11): 225-228. Pidek A. (1987) - Wychów matek pszczelich. PWRiL. Warszawa. Sieger R. (1983) - Das Zuchtverfahren Jenter auf dem Prüfstand. Allgemeine Deutsche Imkerzeitung, 10: 312-317. Skowronek W., Skubida P. (1998) - Wpływ warunków wewnętrznych rodziny wychowującej i sposobu przekładania larw na liczbę i jakość uzyskanych matek. Pszczeln. Zesz. Nauk., 32: 3-18. Weiss K. (1960) - Über die Lebensfähigkeit von Bieneneiern auserhalb des Volkes. Zeitschrift für Bienenforschung, 5(2): 42-48. Wilde J. (2002) - Produkcja mleczka pszczelego bez przekładania larw. Biuletyn Naukowy, 18(5): 107-112. Winston M. L. (1987) - The biology of the honey bee. Harvard Univ. Press. Cambridge, London. Woyke J. (1971) - Correlations between the age at which honeybee brood was grafted, characteristics of the resultant queens, and results of insemination. J. Apic. Res., 10(1): 45-55. Woyke J. (1987) - The cause of inclining of honeybee eggs in comb cells. XXXI Internat. Apicult. Congr., Warsaw 1987, 181.
52 WPŁYW W IEKU JAJ UŻYTYCH DO WYCHOWU MATEK PSZCZELICH NA LICZBĘ UZYSKANYCH MATECZNIKÓW G ą bka J., Ochnio M., Kamiński Z., Madras-Majewska B. S t r e s z c z e n i e Wiek czerwiu użytego do wychowu matek pszczelich ma istotny wpływ na ich jakość. Najlepsze matki uzyskuje się przy wychowie z jaj. Celem doświadczenia było zbadanie czy wiek jaj wpływa na ich przyjmowanie w rodzinach wychowujących. Do pięciu rodzin poddano w czterech seriach po 12 jaj w wieku 0-18, 24-42, i 48-66 godzin. Wszystkie rodziny w pierwszej i trzeciej serii miały czerw otwarty i były 1 dzień bez matki, a w drugiej i czwartej serii nie miały czerwiu otwartego i były 10 dni bez matki. Spośród wszystkich 720 poddanych jaj, pszczoły przyjęły ogółem 44,4% do wychowu matek. Nie stwierdzono istotnych różnic, w ogólnej liczbie przyjmowanych jaj, w rodzinach z czerwiem otwartym, po jednej dobie bez matek (43,6%) i w rodzinach bez czerwiu otwartego, po 10 dniach bez matek (45,3%). Stwierdzono jednak istotne różnice w przyjmowaniu poszczególnych grup wiekowych poddawanych jaj. W rodzinach wychowujących z czerwiem otwartym, po jednej dobie bez matek, nie stwierdzono istotnego wpływu wieku jaj na ich przyjmowanie. Jednak po 10 dniach bez matek, gdy w rodzinach nie było już czerwiu otwartego, pszczoły przyjmowały istotnie najmniej (25%) najmłodszych jaj w wieku 0-18 godzin, a istotnie najwięcej (64,2%) najstarszych w wieku 48-66 godzin. Słowa kluczowe: pszczoła miodna, jaja pszczele, wychów matek pszczelich, rodziny wychowujące.
Journal of Apicultural Science 53