Effect of feeds in developing the hypopharyngeal gland of nosema-free nurse bees for escorting queen honey bees (Apis mellifera) during export
Peng, Yan (2009) Effect of feeds in developing the hypopharyngeal gland of nosema-free nurse bees for escorting queen honey bees (Apis mellifera) during export. Honours thesis, Murdoch University.
In 2006, Japan was one of the markets that contributed to the 4 million dollars live bee sales in Australia. In 2007, the export of queen honey bee from Australia was suspended when Nosema apis was detected in the nurse bees that were escorting the queens during a quarantine inspection off the Japanese ports. Nosemosis or nosema is a worldwide endemic disease caused by N. apis. Infected bees have reduced life span, energy, productivity, and develop deformed glands. As a result of this suspension, many Japanese fruit farmers had to hand pollinate many of their crops while Australian beekeepers suffered financial losses from the loss of trade. Thus, it will be extremely beneficial for both Japanese and Australian farmers if nosema-free nurse bees could be produced and used as escort nurse bees.
Two novel approaches of producing nosema-free bees are proposed: (1) treating infected nurse bees with heat therapy and (2) raising newly hatched nurse bees (HNB) in isolation of infected hives. These approaches may produce nosema-free escort nurse bees. Escort nurse bees feed royal jelly to queen bees in cages during the export journey, thus it is essential that HNB can synthesize and secrete royal jelly. This means that HNB need to develop functional hypopharyngeal glands (HG) in order to secrete royal jelly. Proteins found in pollen are said to be 100 % effective in stimulating full development of the HG. When bees have fully developed and functional HG, they should be able to feed and keep queens alive for the duration of the exporting journey (more than 8 days).
This project investigated whether nosema-free escort nurse bees could be produced by raising them in cages; whether feeding pollen and artificial feed could stimulate full development of the HG; whether there is a relationship between how much bees ate and the extent the HG development; whether the cage-raised escort bees are able to feed and keep 100 % of the queen bees alive during export for at least 8 days; and whether applying heat therapy could cure infection caused by N. apis without killing the bees.
Bees fed nutritionally balanced artificial feeds designated as Sub2, FB, Sub1 had significantly higher head weights (>10 mg) than those fed pollen feeds used in this experiment. Only Sub2 maintained a consistently higher head weight compared to hive-raised mature nurse bees that were fed icing sugar. Bees that consumed PrSub and Sub1 showed a significant (P <0.05) positive correlation between feed consumption and the head weight of individual bees.
Despite carefully isolating combs from hives, newly emerged bees became contaminated with N. apis so nosema-free nurse bees could not be produced. The cage-raised nurse bees fed 16 different pollen and artificial feeds were not able to keep 100 % of the queen bees alive during export for 8 days. Bees that were fed pollen and artificial feed had median survival time of 4 days or less. Queens caged with nurse bees that fed on icing sugar survived much longer than queens caged with nurse bees that fed on pollen and artificial feed. In general, mated queens had significantly longer median survival time than virgin queens.
These findings suggest that protein consumption is not the key factor which regulates the development of the HG. Cage-raised nurse bees suffer abnormal behavioural and physiological developments because of possible lack of appropriate stimulations, hence their inability to properly nurture and feed queen bees. It is clear that cage-raised bees are fundamentally different from hive-raised bees, and so far, the only way to ensure bees develop properly is by raising them in hives. However N. apis spores are in virtually all hives, that means to truly produce nosema-free bees, research should focus on breeding naturally resistant nurse bees or genetically modify bees to become resistant to N. apis.
For decades, beekeepers and researchers have tried to formulate artificial feeds which can substitute pollen. Bees need pollen for protein to build and strengthen hives but pollen is expensive to buy and its availability is unpredictable. To prove that a nutritionally balanced artificial feed such as Sub2 can replace pollen, further research should be conducted in larger cage experiments measuring nutrition composition, longevity and brood rearing.
|Publication Type:||Thesis (Honours)|
|Murdoch Affiliation:||School of Biological Sciences and Biotechnology|
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