As eucalypt pollens contain low concentrations of lipid, enhancing pollen diets with fatty acids was hypothesised to improve honey bee longevity. Different concentrations of linoleic and oleic acid added to eucalypt pollen were trialled in small cages containing approximately 1400 bees each. Bees fed diets of redgum (Corymbia calophylla (Lindl.) Hill & Johnson, formerly Eucalyptus calophylla) pollen had the lowest mortality of 22 diets tested for 6 weeks and had life spans (50%) greater than 42 days. Linoleic acid mixed with a redgum diet in concentrations >6% corresponded to life spans of 24-25 days. Bee longevity appeared to be more sensitive to oleic acid as life spans decreased to 15-21 days when diets had concentrations >2%. The life spans of bees fed soya bean flour were 26 days on low (0.6% lipid) fat, 19 days on defatted and 20 days on full-fat diets. Bees fed lupin flour had a life span of 23 days. Adding redgum pollen to lupin flour caused increased mortality, but addition of pollen to soya bean flour was beneficial. Thus, beekeepers who choose to utilise soya bean or lupin flours as protein substitutes to pollen will have bees with reduced longevity. Bees fed redgum pollen that had been dried, crushed, irradiated and hermetically stored in a cool room for several years had similar longevity to bees fed fresh-collected and frozen redgum pollen.
The parasite, Nosema apis, was found to be widespread among feral populations of honey bees (Apis mellifera) in the south-west of Western Australia. The location, month of collection and whether the feral colony was enclosed in an object or exposed to the environment, all affected the presence and severity of infection. There was no significant difference in the probability of infection between managed and feral bees. However, when infected by N. apis, managed bees appeared to have a greater severity of the infection.
Langstroth hives fitted with a modified lid with an entrance lined with soft felt or steel or plastic pollen traps or hives fitted with plastic pollen traps and sugar-fed significantly increased the pollen count on the bodies of exiting honey bees. In terms of utilising the research findings in contract pollination service where costs can determine profitability, the recommendation is for a trial in a commercial orchard (e.g. almond, apple, avocado, plum) of sugar-fed single hives fitted with plastic pollen traps. Despite the bees' destruction of the felts lining the modified lid entrances, the soft felt liner might be a worthwhile inclusion into any field trial.
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