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Chalkbrood, caused by Ascosphaera apis (Maassen ex Claussen) Olive & Spiltor, is a cosmopolitan fungal disease of honey bee larvae (Apis mellifera L.) for which there is no chemotherapeutic control. Using in vitro larval rearing methods, lysozyme-HCl, a food-grade antimicrobial extracted from hen egg albumen, was found to suppress chalkbrood at levels of 0.75-1.5% (g/mL) of larval diet. In field trials, lysozyme-HCl did not affect adult bee survival or brood production and did effectively suppress the development of chalkbrood disease. Daily chalkbrood mummy production decreased by a factor of 10 in colonies treated with three treatments of 6000 mg of lysozyme-HCl when compared with infected, untreated controls and reduced disease symptoms to levels observed in uninfected colonies. Honey production was also found to be significantly negatively correlated with increased disease severity. Lysozyme-HCl is a promising safe therapeutic agent for the control of chalkbrood in honey bee colonies.

In an earlier project completed in our laboratory a seasonal fluctuation in Phosphoglucomutase (PGM) phenotype frequencies was found, so that the winter bees were almost all heterozygotes and long lived than the summer bees among which homozygotes were significantly at high frequencies at Pgm locus. Same results were obtained in populations of three subspecies, A. m. meda, A. m. caucasica, and A. m. carnica from different climatic regions. In the current study environmental cues related with seasonal change in PGM phenotype frequency was examined along with the correlation between PGM heterozygosity and overwintering success. Cessation of food influx was found to be effective by itself as an environmental cue that causes a sudden and sharp increase in PGM heterozygosity. In addition to that, PGM heterozygosity of the colonies with greater overwintering success was found to be significantly higher than the ones with intermediate or low overwintering success. Benefiting from the previous studies and the results of current study, ethyl oleate was suggested as a chemical signal that functions in the regulation of PGM heterozygosity.

ABSTRACT MORPHOMETRIC, MtDNA AND MICROSATELLITE ANALYSIS IN HONEYBEE POPULATIONS (Apis mellifera L.) OF NORTH AND NORTHWEST IRAN Morphometric measurements, mitochondrial DNA analyses and 5 microsatellite loci were used to investigate variation in the honeybee populations of Iran and comparing it with the Turkish populations. Five honeybee populations were sampled from North and west north of Iran. In morphometric aspect of the study 23 characters were measured from left forewings and hindlegs of honey bee samples. The data were analysed by multivariate statistical analyses. By using mtDNA analyses length polymorphism of the intergenic region COI-COII of mitochondrial DNA was studied. After amplification of this region by the polymerase chain reaction, DraI enzyme was used for restriction of amplified region. Results of mtDNA studies show no diversity between four populations and all of them exhibit the same C1 pattern. Five microsatellite loci (A7, A24, A28, A43 and A113) were used in this studies.A high level of average heterozygosity changing between 0.611 and 0.709 was detected in Iranian honey bee populations, and a significant degree of polymorphism was observed. Although Urmia, Sarein and Viladereg populations are similar, Amol population which has located in northern Iran shows a significant difference from other populations. Result obtained form morphometric studies are supporting microsatellite analyses. By comparing data obtained form Iranian honey bee populations with Turkish population (Hakkari), western populations (Urmia, Sarein and Viladereg) are more similar to Hakkari population. It is found Amol is significantly different form other populations and better represents Iranian honeybee.

Western honey bees (Apis mellifera; hereafter honey bees) provide vital pollination services to global agriculture and biodiversity. However in recent years they have experienced severe population declines in many regions of the northern hemisphere. Although causes of these honey bee declines are not well understood, multiple pressures such as changes in land-use and climate, management issues, and introduced parasites are believed to be responsible. First described in honey bees in 2006 during a period of high colony mortalities, the microsporidian gut parasite Nosema ceranae became of great concern. In this dissertation I investigated the distribution, management, virulence, and inter-specific interactions of this introduced species. First, I described and clarified the multiple pressures believed to influence honey bee health, including N. ceranae, especially in relation to the mysterious phenomenon Colony Collapse Disorder. I then surveyed colonies in Maritime Canada for N. ceranae and the historic honey bee microsporidian Nosema apis. Although both species were present at a regional scale, intensive sampling in Nova Scotia revealed that N. ceranae was highly prevalent compared to the historic congener. Next, I investigated two potential management options for the parasite. Chemotherapy using the fungicide fumagillin reduced N. ceranae spore intensity but had no effect on colony survival, and indoor over-wintering did not reduce spore intensity but was associated with increased colony survivorship in spring. Using a comparative approach, I observed that N. ceranae infection significantly reduced honey bee longevity in the laboratory but did not influence overall colony health or strength in the field. Last, a laboratory study demonstrated reduced spore production during N. ceranae and N. apis co-infection, possibly due to inter-specific competition that has resulted in the displacement of the historic Nosema species by N. ceranae in many global regions. This dissertation provides crucial information on biology and management of N. ceranae that can be used towards the development of an integrated pest management strategy, and for future studies investigating factors that may influence the parasite’s distribution, virulence, and inter-specific interactions.

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The aim of this thesis was to monitor the Varroa destructor parasitic mite in correlation with the microclimatic conditions of the Carniolan honey bee (Apis mellifera carnica). The rate of infestation of selected bee colonies at different locations was assessed in three-day intervals. At the same time, the microclimate in the hives was observed. The monitoring took place from April to mid-October. Also, the effect of the microclimate on the mite fall count was evaluated. During the whole evaluation, the highest average daily fall count was 2.08 mites per day at honeybee colonies at location 1 and 2; 1.97 at location 3. There was no statistically significant difference (P > 0.05) between those locations. The comparison of fall count between the moths of observation revealed, that highest fall count was during September (3.03 mites per day) and the lowest fall count was in April (0.41 mites per day; P 0.001). The rates of dependence (assessed by correlation analysis) between the fall count and microclimatic conditions in individual colonies varied. The strongest correlation between hive temperature and fall count (r = -0.45, P 0.05) was found at location 2. A low correlation was found at location 1 (r = -0.17, P 0.05). On the other hand, location 3 showed an insignificant and inconclusive correlation between hive temperature and fall count (r = 0.003, P > 0.05). The aggregate data (without distinction of location or month) showed significant (P 0.05) correlation between fall count and hive temperature (r = -0.14). The correlation between relative air humidity in hive and the fall count was statistically insignificant and low (r = -0.02, P > 0.05). The results revealed that the degree of correlation between the hive microclimate and the development (fall count respectively) of the Varroa destructor population is different for each colony. The monitoring of the dead Varroa destructor females is an appropriate complementary tool to diagnose a colony's infestation. The statistical analysis confirmed that with the decreasing summer and end-of-summer temperatures the Varroa destructor population grows and it is necessary to take measures to suppress its growth due to the development of the honey bee long-term winter generation.