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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #229436
Title: The Role of Fatty Acids in the Mechanical Properties of Beeswax

Author
item BUCHWALD, ROBERT - UNIVERSITY OF CALIFORNIA
item BREED, MICHAEL - UNIVERSITY OF COLORADO
item BJOSTAD, LOUIS - COLORADO STATE UNIVERSITY
item Hibbard, Bruce
item GREENBERG, ALAN - UNIVERSITY OF COLORADO

Submitted to: Apidologie
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2009
Publication Date: 10/1/2009
Citation: Buchwald, R., Breed, M.D., Bjostad, L.B., Hibbard, B.E., Greenberg, A.R. 2009. The Role of Fatty Acids in the Mechanical Properties of Beeswax. Apidologie. 40:585-594.

Interpretive Summary: Beeswax is a mixture of many organic compounds, including hydrocarbons, wax esters, and fatty acids. While the composition of beeswax is well known, how each of the components contribute to the overall functions of wax is less well understood. Because fatty acids in beeswax also serve as social signals, we explored the functional significance of the fatty acids, using standard engineering techniques for measuring the mechanical properties of materials. The removal of the fatty acids from beeswax results diminished yield stress, resilience, stiffness, and proportional limit stress of beeswax samples. Addition of specific fatty acid, stearic acid, to beeswax enhanced all of these properties except resilience. Artificial wax mixtures showed a positive correlation between the amount of stearic acid in the wax mixture and yield stress. Further experiments with artificial mixtures showed that the unsaturated fatty acids found in beeswax behave similarly, with respect to their effects on the mechanical properties of artificial wax mixtures. Gas chromatography revealed significant intercolonial variation in fatty acid concentration, particularly among the unsaturated fatty acids. These findings support the hypothesis that fatty acids are important in conferring appropriate mechanical properties to beeswax.

Technical Abstract: Beeswax is a mixture of many organic compounds, including hydrocarbons, wax esters, and fatty acids. While the composition of beeswax is well known, how each of the components contribute to the overall functions of wax is less well understood. Because fatty acids in beeswax also serve as social signals, we explored the functional significance of the fatty acids, using standard engineering techniques for measuring the mechanical properties of materials. The removal of the fatty acids from beeswax results diminished yield stress, resilience, stiffness, and proportional limit stress of beeswax samples. Addition of stearic acid to beeswax enhances all of these properties except resilience. Artificial wax mixtures show a positive correlation between the amount of stearic acid in the wax mixture and yield stress. Further experiments with artificial mixtures showed that the unsaturated fatty acids found in beeswax behave similarly, with respect to their effects on the mechanical properties of artificial wax mixtures. Gas chromatography revealed significant intercolonial variation in fatty acid concentration, particularly among the unsaturated fatty acids. We interpret these findings with respect to the mechanical properties of beeswax and the role of fatty acids in communication among bees.