الفهرس 
introduction
Pollen sourcesOnly 14 pages are availabe for public view
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Abstract
Studies on pollen quality and their physiological effects on honey bee (Apis mellifera L.) Honey bee pollen nutrition plays a fundamental role in the health and vigor of bee colony. Annually significant proportions of honey bee colonies are dying and the production of beekeeping is scarce. The nutritional stress among other factors may be responsible for high colonies mortality percentage. The present study aimed to accomplish the following objectives: (1) identify the dominant pollen sources and determine their amino acids content, (2) Study the effect of single or poly floral pollen types on some physiological parameters, 3) Study the rate of protein diets consumption, (4) Assess the effect of poly floral pollen on performance of bee flight and (5) Study the effect of pollen diets on bee immunocompetence and antimicrobial peptides production in honey bee workers. The experiments were conducted at the laboratory and apiary of the Institute of Zoology, University of Graz, Austria during active season of honey bee colonies from April to September 2014 and 2015. The following results were obtained: (1) For identifying the dominant pollen sources and determining their nutritive value, pollen loads were collected during season of 2014 using pollen traps in two regions. Pollen pellets were separated according to their colour then traced back to their plant species source. Four dominant sources of bee forage plant species were recorded: Sunflower (Helianthus sp.), Mustard (Sinapis sp.), Asparagus (Asparagus sp.) and Chestnut (Castania sativa). Regarding to pollen pellets weight, the pollen pellets of Sinapis sp. were recorded as the highest weight (1338 mg/100 pellets), while the pollen pellets of Helianthus sp. were recorded as lowest one (737 mg/100 pellets). In respect to the amino acids content, the analysis of dominant pollen types identified eighteen amino acids in the main four pollen types which collected during active season. Valin, Isoleucine and Lecuine, the amino acids which consider the most required for young bees were the lowest in sunflower pollen pellets comparing to all other tested pollen. The highest essential amino acids concentration was recorded in Asparagus pollen (186.2 mg/g). However, the lowest one was recorded in sunflower (Helianthus sp.) pollen (104.7 mg/g). Bee’s preference of dominant pollen types was also determined. Four free flight honey bee colonies equal in strength were used. Pollen diets were administrated using multi choice test. Results indicated that the highest preferred pollen diet was recorded for Castania sativa pollen followed by mixed pollen dough with significant differences among other diets. (2) Study the physiological effects of different pollen and protein diets on honey bee workers, two experiments were conducted as follows. In the first experiment, preliminary test on food consumption rate, development of hypopharyngeal glands and acid gland was carried out under laboratory conditions. Small groups of newly emerged honey bee workers in cages were used. The results indicated that, the maximum food consumption was recorded at age of 3 days old. The maximum development of hypopharyngeal glands acini was recorded on age of 5 days (3.168 μm³) and the maximum acid gland sac volume were recorded on age of 18 days old (1.022 mm³). In the second experiment, the nutritive effect of different 6 protein diets was tested. The difference in food consumption among the six protein diets were used to feed the caged honey bees was obseved. The highest accumulative food consumption was recorded for mixed pollen diet over 18 days old and the lowest one was recorded for the Asparagus pollen diet. The protein diets had different effect on hypopharyngeal acini volumes at the three investigated ages. The volumes of the hypopharyngeal acini were the largest at the age of 5 days old in all diets except the protein-free diet (sugar solution) and significantly differed in comparison to the ages 12 and 18 days. Hypopharyngeal glands acini were developed best in bees fed with Asparagus, Castanea and mixed pollen diets. The volume of the acid gland sac of bees fed with all diets was significantly larger at day 12 than days 5. No significant difference was recorded between day 12 and 18. Bees aged 12 days old fed on Asparagus, Castania and mixed pollen had significantly better development of acid gland sac than those deprived of protein diet. (3) Effect of feeding poly floral pollen during nursing period of honey bee workers on flight performance Two experiments were carried out to study the effect of adult nutrition on: a- Flight performance An experiment was done using two small groups of newly emerged honey bee workers. The first group was received pollen diet ad libitum during the first 16 days of the experiment and the second group was received only sugar solution as pollen deprived bees. Flight performance of individual honey bee workers aged 16 to 29 days old was tested. Flight characteristics as flight time, distance, speed average maximum speed per minute or per round and mean metabolic powers were calculated. After the flights, the fresh and dry weights of head, thorax and abdomen, for each bee, were determined. The following results were obtained: 1- Majority of bees (88.5%) that received pollen diet for the first 16 days of their life successfully flew in flight mill as compare to 79.3% of pollen deprived bees, with insignificant difference between both two groups. 2- The two groups of bees did not differ significantly in their speed average for the entire period of flight but the group of bees fed pollen were significantly faster in the early period of acceleration, whereas, the group of pollen deprived bees was significantly faster in the final deceleration phase of both flights. 3- The two groups did not differ in the maximum speed either per minute or per round. 4- For both pollen fed and pollen deprived bees, the averages in time, distance and speed were higher in 2 M flight. 5- Pollen fed and pollen deprived did not differ in abdomen fresh weight, but fresh weight of head and thorax were significantly higher in pollen fed bees than those of pollen deprived bees. 6- Dry weights of worker body parts (head, thorax and abdomen) were significantly higher in pollen fed than in pollen deprived bees. b- Compensation feeding of early pollen deprivation An experiment was carried out under laboratory conditions with two small groups of newly emerged honey bees in plastic cages. The first group was received pollen diet from day one until day 16 (full consumption bee) and the second group was prevented to receive pollen in the first 7 days and started to receive pollen at day 8 until day 16 (constraint consumption bees). Daily food consumption was recorded and the mortality percentages were calculated. After the experimental period, fresh and dry weights of bee parts were determined. The following results were obtained: 1- The bees with full pollen supply cumulatively consumed a mean of 86.6 mg protein diet in the first 16 days of their life and 25.5 mg only during the age period from 8 to 16 days. The bees constrained to pollen consumption consumed a mean of 44.3 mg pollen in total at ages 8 to 16. 2- Higher mortality (17.7%) was recorded in bees group with constraint access to pollen diets as compared to bees allowed full pollen supply (7.3%). 3- Constraint pollen consumption during early life of honey bee worker reduced fresh and dry weights of the body parts (head, thorax and abdomen) compared to bees allowed full pollen consumption. The present results demonstrated the importance of protein consumption in young adult bees for developing body parts, flight muscles and improving flight performance. 4) Effect of protein nutrition on the gene expression and production of honey bee antimicrobial peptides (AMP) ”apidaecin”. An experiment was conducted under laboratory conditions. Different 7 diets were administrated to newly emerged honey bee workers in cages for 18 days. All offered diets were consumed by bees. Two body parts of honey bee workers dissected. The thorax was used for quantification of apidaecin I isoform. The abdomen was used for quantification of gene expression of apidaecins. The results indicated that: Honey bee workers without dietary protein showed a lower concentration of antimicrobial peptide (apidaecin I isoform). However, bees fed mixed pollen diet contained an amount of 25.6 ng of the peptide recalculated per thorax unit. Also, the bees fed Asparagus pollen or Castanea pollen showed even higher apidaecin I amounts, although, the differences were not statistically significant. The expression levels of the respective genes were increased by feeding newly emerged honey bee workers with monofloral pollen or the pollen substitute ”Feedbee®”. The present results administrated the importance of bee diet composition for producing antimicrobial peptides ”apidaecin” which contribute the increase of bee immunocompetence and improve colony health.