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Title: The application of chromatographic techniques and behavioural bioassays towards isolating and characterising honey bee phagostimulants
Author: Bridgett , Richard James
ISNI:       0000 0004 6350 8389
Awarding Body: Keele University
Current Institution: Keele University
Date of Award: 2016
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Numbers of honey bees (Apis mellifera) have fallen over recent years, potentially (in part) due to weaker colonies being more susceptible to disease, and consequently collapse. To boost colony strength and population, high-protein artificial or supplemental diets can be provided for bee consumption. This thesis investigated whether an integrated use of chromatographic techniques, including GC-MS, HPLC, LC-MS, and countercurrent chromatography (CCC), with bioassays conducted using bee colonies (in a process of bio-guided fractionation), can aid the isolation and characterisation of naturally occurring feeding stimulants (phagostimulants) within pollens. Adding these phagostimulants to such diets could increase diet consumption. A novel method for effectively conducting multiple-choice (more than two choices) bioassays, which assess diet palatability using a reduced number of colonies, has been developed. This method, is thought to be the first direct comparison of the increased feeding stimulation provided by added solvent extracts (that vary in polarity) of pollen to artificial diets. Using this method, experimental data obtained suggests that more polar extracts may provide increased stimulation over less polar extracts. An original application of CCC then facilitated some large-scale fractionation of the pollen extract material contained in methanol extracts of pollen. Collected fractions had their stimulatory activity tested, and obtained results suggest that the majority of the extractable material (c.a. 75% by mass and including the sugars) from foraged pollens provide little feeding stimulation to bees. However, increased stimulation was delivered by a complex (> 100 compounds) fraction believed to contain fatty acids and sterols, as well as other unknowns. Finally, a preliminary chemometrics study was carried out to reveal compounds that are present in either distinct or equivalent abundances in the chemical profiles of multiple pollen species, and the obtained active fraction. Through this, the potential future use of chemometics to aid phagostimulant characterisation has been evaluated.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available