Microstructure and microtexture characterization of avian eggshells

M. AVALOS; V. TARTALINI; P. RISSO; A. V. LOPEZ; M. E. HAUBER; J.C. REBOREDA; R.E. BOLMARO

Saint George

Conferencia; 18th International Conference on Textures of Materials; 2017

Brigham Young University, Utah.

The avian eggshell is the final product of a calcium carbonate biomineralization process. As a result, it mainly consists of calcite crystals of different sizes and orientations. Texture and microstructure are structural traits that influence the mechanical properties of the eggshell. These structural characteristics are of particular interest for evolutionary interactions in avian brood parasitism behavior because thicker parasitic eggshells are more resistant to punctures by hosts or conspecifics. In this work eggshell samples of three species of avian brood parasites (Icteridae: Molothrus) and seven hosts (Icteridae, Tyrannidae, Cardinalidae, Mimidae, Troglodytidae) were analyzed to characterize the microtexture and microstructure of the eggshell in order to document variation between species. Low vacuum Electron Backscatter Diffraction (EBSD) scans were performed in the eggshells of the selected avian species in the Radial-Tangential planes. We complemented these scans with X ray pole figures from the same species? samples. The results show that together with crystal size/thickness relationship, the networks of grain boundaries seem to be a microstructural characteristic to take into account for understanding the resistance to puncturing. The analysis of EBSD results indicated that the model of grain occupation was not sufficient to explain the microstructure variation across different species? eggshells.