Macro- and trace elements content in honeybee pollen loads in relation to the harvest season

The content of macro-and trace elements in honeybee pollen loads collected from the Al-Ahsa oasis, Saudi Arabia during spring, summer, autumn, and winter in 2018/2019 were determined. After critical screening and observation, we found that the major pollen floral resources were rapeseed, sunflower, summer squash, and date palm. The highest values of sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P) and manganese (Mn) were found in pollen loads trapped during spring and winter. The highest levels of copper (Cu) and iron (Fe) were found from pollen loads harvested during autumn, while the highest content of zinc (Zn) was found in pollen loads collected during the summer. Higher concentrations of the essential elements (Na, K, Ca, Mg and P) for human nutrition found in pollen loads collected during the spring and winter seasons, make them valuable food supplements. Finally, the elements contained in pollen loads can be related to the season of pollen load collection.

Protein content and amino acids composition of bee-pollens from major floral sources in Al-Ahsa, eastern Saudi Arabia

Protein content and amino acids composition of bee-pollens from major pollen floral sources in Al-Ahsa, Saudi Arabia were determined to investigate the nutritive value of pollen protein relative to requirements of honeybees and adult humans. The major pollen sources were alfalfa, date palm, rape, summer squash, and sunflower. Bee-pollens from alfalfa and date palm showed high content of crude protein and amino acid concentrations. Bee-pollen from sunflower had low content of those components. Eighteen amino acids were found in bee-pollens from the five major floral sources. The highest concentrations of individual amino acids valine, leucine, isoleucine, phenylalanine and proline were obtained from alfalfa bee-pollen; lysine, arginine, cysteine, tryptophan and tyrosine from date palm; methionine, histidine, glycine and alanine from summer squash; threonine, serine and glutamic acid from sunflower; and aspartic acid from rape bee-pollen. The amino acid composition obtained from sunflower bee-pollen showed the lowest concentrations of the essential amino acids: isoleucine, leucine, methionine, phenylalanine and valine. Apart from methionine, arginine and isoleucine, the essential amino acids of bee-pollen from alfalfa, date palm, summer squash and rape exceeded the honeybees' requirements. Methionine was the limiting amino acid in bee-pollens from the five selected sources. Concentrations of essential amino acids in the tested bee-pollens were variable and significantly correlated to their botanical origin of pollen. Bee-pollens from alfalfa, date palm and summer squash was found to be rich source of protein and amino acids for bees and for humans.

Effect of gut bacterial isolates from Apis mellifera jemenitica on Paenibacillus larvae infected bee larvae

The probiotic effects of seven newly isolated gut bacteria, from the indegenous honey bees of Saudi Arabia were investigated. In vivo bioassays were used to investigate the effects of each gut bacterium namely, Fructobacillus fructosus (T1), Proteus mirabilis (T2), Bacillus licheniformis (T3), Lactobacillus kunkeei (T4), Bacillus subtilis (T5), Enterobacter kobei (T6), and Morganella morganii (T7) on mortality percentage of honey bee larvae infected with P. larvae spores along with negative control (normal diet) and positive control (normal diet spiked with P. larvae spores). Addition of gut bacteria to the normal diet significantly reduced the mortality percentage of the treated groups. Mortality percentage in all treated groups ranged from 56.67% up to 86.67%. T6 treated group exhibited the highest mortality (86.67%), whereas T4 group showed the lowest mortality (56.67%). Among the seven gut bacterial treatments, T4 and T3 decreased the mortality 56.67% and 66.67%, respectively, whereas, for T2, T6, and T7 the mortality percentage was equal to that of the positive control (86.67%). Mortality percentages in infected larval groups treated with T1, and T5 were 78.33% and 73.33% respectively. Most of the mortality occurred in the treated larvae during days 2 and 3. Treatments T3 and T4 treatments showed positive effects and reduced mortality.

Impact of insect pollinators on yield and fruit quality of strawberry

Investigations were conducted to determine the insect pollinators visiting strawberry blossoms and their impact on fruit production. Various pollinators observed during the blooming period of strawberry were viz. Apis mellifera, Apis cerana, Apis florea. Apis dorsata, soil nesting solitary bees such as Andrena leana and A. ilerda, butterflies, houseflies, syrphid flies and some beetles. The percentage of fruit set was much higher in open pollinated plants than control. There was 11.20 per cent malformed fruit in open pollinated plots as compared to 17.44 per cent in controlled one. Further the fruits obtained from the open pollinated plants were of good quality and large as compared to the controlled plants. Growers are recommended to take advantage of the several pollinators, either the honey bee or the native pollinators (Syrphidae and native bees). The importance of diversifying pollination sources, avoiding the dependence on a single specific group is stressed. This study also suggests measures which envisage the conservation, establishment and increase of native pollinators’ populations in the typical agro-ecosystem of region.