A Biomechanical Perspective on Beeswax

Abstract

American Entomologist • Volume 51, Number 1 We are interested in how structural materials used by bees relate to the evolution of complex social communication. In particular, we explored how fatty acids affect the mechanical function of beeswax (Fig. 1). This interest led us to compare the mechanical properties of the waxes of a wide variety of social bees. These fatty acids are major components in beeswax (Aichholz and Lorbeer 1999) and are also used by bees in social recognition (Breed 1998, Breed et al. 2004). Although the nature of beeswax has been explored in detail in the Western honey bee, Apis mellifera (Hepburn 1986), little is known of the waxes of other apid bees. Bees in the family Apidae exhibit different levels of sociality, ranging from solitary to primitively eusocial to highly eusocial. In addition to differences in social organization, apids also display differences in nest construction. The three most highly derived subfamilies in the family Apidae are the Bombinae (bumble bees), Meliponinae (stingless bees), and Apinae (honey bees). Aside from parasitic species, the bumblebees are primitively eusocial. The queens and workers are only slightly different morphologically, and reproductive dominance is maintained via aggressive behavior of the queen. The relatively small colonies dwell in annual nests (Michener 1974). These nests are constructed by the foundress, usually in an abandoned rodent’s nest, and consist of several ovular wax cells roughly stacked on one another. All stingless bees and honey bees are highly eusocial. The queens and workers are morphologically very different; and at least in Apis, reproductive dominance is maintained through pheromones. The relatively large perennial nests of these bees are most often found in cavities such as hollow trees. Stingless bees construct their nests with highly organized, horizontal combs where brood are raised; ovular storage pots are roughly stacked separately from the brood comb. In addition to endogenously produced wax, stingless bees incorporate large amounts of plant material in their nests. Conversely, honey bee nests comprise one or many vertically hanging combs. In honey bees, the combs are constructed almost exclusively from endogenously produced wax containing primarily esters, straight-chained hydrocarbons, and fatty acids (Tulloch 1980). These beeswax structures gain their mechanical properties from two distinct sources. For a structure to function properly, it must possess the right combination of material and geometry. The mechanical properties of the building materials have a great influence on the properties such as A Biomechanical Perspective on Beeswax