Maciej Siuda

Onset of oviposition by honey bee queens, mated either naturally or by various instrumental insemination methods, fits a lognormal distribution

Summary It is commonly believed that instrumentally inseminated honey bee queens initiate oviposition much later than naturally mated queens. A large scale investigation was therefore conducted on 1675 queens. Naturally mated queens initiated oviposition 2 to 23 (mean 6.8) days after the start of mating flights and the mode occurred 2.8 days earlier. Queens inseminated instrumentally with 8mm3 of semen initiated oviposition 3 to 21 (mean 9.1) days after insemination and the mode occurred 3.1 days earlier. Thus, the mean and the mode of the onset of oviposition occurred only 2.3 or 2 days later in instrumentally inseminated queens than in naturally mated queens. Different treatments of instrumentally inseminated queens accelerated or delayed the onset of oviposition by only one day in relation to instrumentally inseminated queens not additionally treated. The distribution of the onset of oviposition was skewed positively in both naturally mated queens and instrumentally inseminated queens and fitted a lognormal distribution. We therefore recommend presentation of the mode value in all future papers concerning the onset of oviposition by both naturally mated queens and instrumentally inseminated queens.

Distribution of Varroa destructor between swarms and colonies

SUMMARY Bee colonies reproduce by colony division during swarming. In colonies infested by the parasitic mite, Varroa destructor, colony division will at the same time split the mite population between the swarms and the remaining parent colonies. The present investigation compares infestation of swarms with that of parent colonies. We found that an average of 25 ± 9% of mites left the colonies with natural swarms, while 75 ± 9% remained in parent colonies of which 39 ± 11% were on bees and 36 ± 10% were within sealed brood cells. The relative swarm infestation did not differ from that of the remaining parent colony in this study, but very low proportions of mites within sealed worker brood and a clear negative correlation to the proportion of mites in sealed brood strongly suggest that swarm infestation is asymmetric and lower than that of the remaining colonies.

Wintering Reserve Queens in Mini-Plus and 3-Comb Nuclei

Abstract The aim of this study was to develop an effective method of overwintering reserve honey bee queens in two-storey mini-plus mating nuclei and in 3-comb nuclei (frames 36 x 26 cm, Wielkopolski hive). The assay was performed during three wintering seasons (2005 - 2008) parallel at two centers in Poland: the Division of Apiculture at the University of Life Sciences (SGGW) in Warsaw, and the Apiculture Division at the University of Warmia and Mazury (UWM) in Olsztyn. The results showed that 59% of queens overwintered in mini-plus nuclei and 77% in 3-comb nuclei. Among queens in mini-plus nuclei 63% overwintered in bee yard and only 55% in cellar. Within queens in 3-comb nuclei, 62% overwintered in Olsztyn and 91% in Warsaw. The highest survival rate of 93% was observed in Warsaw during the first season. Due to low survival rate, it is not recommended to overwinter the queens in miniplus nuclei.

The Effect of Various Storage Methods on Organoleptic Quality of Bee Pollen Loads

The Effect of Various Storage Methods on Organoleptic Quality of Bee Pollen Loads The aim of this research was to evaluate the effect of storing frozen pollen loads in controlled and/or air atmosphere, on organoleptic properties of the product. Collected pollen loads were cleared of mechanical impurities and preserved as follows: frozen and stored in air atmosphere; frozen and stored in an artificial atmosphere of a carbon dioxide and nitrogen mixture (30% CO2, 70% N2); frozen and stored in pure nitrogen (100% N2); frozen and stored using a vacuum system; dried out at ca. 40°C and stored in air atmosphere. In an organoleptic study, all tested pollen samples, irrespective of their storage method, were evaluated positively. The studied storage factors did not affect the shape, specific identity or aroma of pollen loads. The average point scores obtained for these features were similar in all groups. Storage conditions did influence the color and flavor of stored pollen loads. The experiment revealed significant differences in the perception of taste and aroma of tested pollen samples depending in the sex of the testing person. The taste and aroma of pollen loads were more appealing to men than to women testers. Wpływ Sposobu Przechowywania na Właściwości Organoleptyczne Obnóży Pyłkowych Celem pracy było określenie wpływu metod przechowywania mrożonych obnóży pyłkowych w atmosferze gazów kontrolnych i powietrza atmosferycznego na właściwości organoleptyczne tego produktu. Doświadczenie wykonano w Katedrze Pszczelnictwa UWM w Olsztynie. Pozyskane obnóża pyłkowe oczyszczono i utrwalono następującymi sposobami: zamrożono w naturalnej atmosferze, zamrożono z wymianą atmosfery na mieszaninę dwutlenku węgla i azotu (30% CO2 i 70% N2), zamrożono z wymianą atmosfery na czysty azot (100% N2), zamrożono i zamknięto próżniowo, oraz wysuszono w temp. około 40°C. Wszystkie próbki obnóży niezależnie od sposobu przechowywania uzyskały pozytywne oceny podczas badań organoleptycznych. Oceniane warunki przechowywania nie wpływały na kształt, tożsamość oraz zapach obnóży pyłkowych, a uzyskane średnie oceny punktowe były podobne we wszystkich grupach. Warunki przechowywania wpłynęły na barwę oraz smak przechowywanych obnóży. Stwierdzono, istotny wpływ płci osób oceniających na odbiór wrażeń smakowych i zapachowych obnóży pyłkowych. Smak i zapach obnóży pyłkowych był bardziej akceptowany przez mężczyzn niż kobiety.

Correlated and direct responses to selection for high and low pollen yield in a small, open population of Apis mellifera carnica

Summary Selection for high-pollen (HP) and low-pollen (LP) yield was performed in Apis mellifera carnica for four generations using pollen traps. HP and LP yields were compared with an unselected control (C) line. Our procedure provided a constant inflow of new genes from the C line to the HP and LP lines that is useful in small apiaries. A significant (p < 0.01), asymmetrical (greater in HP), direct response to selection was observed. Correlated responses were also detected in: the pollen forager ratio (proportion of the pollen forager number to the total forager number) and pollen forager number in the HP line; and single-pollen load weight, honey yield, stored pollen area, and brood area in the LP line. No response was found in the total forager number. Correlated selection pressures were detected in the pollen forager ratio (in HP and LP), the stored pollen area (mostly in LP), and the brood area (slight in LP). Taken together, these observations indicate that pollen yield is determined by a small number of major genes. The selection results and the correlated response patterns suggest that pollen yield, pollen forager ratio, and the stored pollen area were mostly genetically correlated, but correlations between the pollen yield and the other traits examined resulted from the environmental background or from worker interrelations within the colony that function as a network of mutually dependent processes. The correlated response was also asymmetrical; it was greater and involved more of the monitored traits in LP. Consequently, the high pollen-hoarding genetic potential decrease results in the reduction of colony fitness and other traits, but its increase does not impact on the other traits or fitness values, as within-colony inter-trait relationships are involved.

The condition of honey bee colonies (Apis mellifera) treated for Varroa destructor by different methods

The aim of this study was to examine how different methods of varroa treatment affect the condition of honey bee colonies. There were four groups of bee colonies formed, with 25 colonies per group: group I (MT): chemotherapy only; group II (IT): integrated varroa treatment; group III (NT): natural compounds treatment; and group IV (C): control group, without any varroa treatment. After the first year of assay, the autumn measurements revealed that the colonies in the control group had significantly more combs inhabited by bees than the colonies in the groups treated for varroa with chemotherapy. In the following year, the colonies in the control group weakened so much that eventually their average number of combs inhabited by bees for the third assay year was significantly lower than in the remaining groups (from 13.5 in the NT group to 14.8 in the IT group), with only 10.2 inhabited combs in the C group. The varroa treatment applied in the treated colonies did not reduce the winter debris weight in comparison to the non-treated ones. We did not observe any negative effect of the selected varroa treatment methods on the condition of bee colonies. Failing to apply varroa treatment results in the gradual and systematic decrease in the number of combs inhabited by bees and condition of bee colonies and consequently, in their death. Estado de las colonias de abejas melíferas (Apis mellifera) tratadas por Varroa destructor con diferentes métodos El objetivo de este estudio fue examinar cómo los diferentes métodos de tratamiento de la varroa afectan la condición de las colonias de abejas melíferas. Se formaron cuatro grupos de colonias de abejas, con 25 colonias por grupo: grupo I (MT) -sólo quimioterapia, grupo II (IT) -tratamiento integrado de la varroa, grupo III (NT) -tratamiento con compuestos naturales- y grupo IV (C) -grupo control, sin ningún tratamiento de la varroa. Después del primer año de ensayo, las mediciones de otoño han revelado que las colonias del grupo control tenían un número significativamente mayor de panales habitados por abejas que las colonias de los grupos tratados contra la varroa con quimioterapia. Durante el año siguiente, las colonias del grupo de control se debilitaron tanto que, finalmente, su número medio de panales habitados por abejas en el tercer año de ensayo fue significativamente menor que el número de panales habitados por abejas de las colonias del resto de los grupos (de 13,5 en el grupo NT a 14,8 en el grupo IT), con sólo 10,2 panales habitados en el grupo C. El tratamiento de la varroa aplicado en las colonias tratadas no redujo el peso de los escombros invernales en comparación con los no tratados. No se observó ningún efecto negativo de los métodos de tratamiento de la varroa seleccionados sobre el estado de las colonias de abejas. Si no se aplica el tratamiento contra Varroa destructor, se produce una disminución gradual y sistemática del número de panales habitados por abejas y del estado de las colonias de abejas y, en consecuencia, su muerte.

The influence of sublethal doses of imidacloprid on protein content and proteolytic activity in honey bees (Apis mellifera L.)

The effect of sublethal doses of imidacloprid on protein content and activity of proteases on honey bees was analyzed. The study was conducted in three experimental groups: colonies from groups BE-5 and BE-200 were contaminated with 5 and 200 ppb of imidacloprid, respectively, via their food supply (syrup and pollen), while group BE was used as control (untreated). Bee samples were collected 3 and 10 weeks after feeding started. Protein concentration in bee tissue extracts was analyzed with reference: (a) to the dose of imidacloprid; and (b) duration of exposure to the chemical. The average quantity of protein content was significantly higher at the 3-week interval than in the 10-week interval and the bees from control colonies (BE) had significantly higher protein contents than contaminated bees (BE-5 and BE-200), even 3 weeks after feeding with imidacloprid started. Similarly, the activity of proteolytic enzymes (proteases) was found to be dependent on the dose of imidacloprid used, compared to bees from control colonies showing significantly higher activity.