The mechanical properties of bettong and potoroo foods

Abstract

Potoroid marsupials (bettongs and potoroos of the family Potoroidae) are considered ecosystem engineers because of the roles they play in maintaining biodiversity. However, severe declines since European arrival have necessitated intense conservation efforts. Vital to these efforts is an understanding of the physical challenges that define their niches. The mechanical properties of their foods, such as toughness and stiffness, represent a physical interface with the environment that can contribute to quantitatively defining their niches. Here, we provide mechanical property data from wild bettong and potoroo foods, such as roots and tubers, fruit, fungi, invertebrates, seeds, and leaves. Toughness ranged from approximately 56.58 J/m2 (fungal sporocarp of Descolea sp.) to 2568.15 J/m2 (tubers of the blue yam, Brunoniella australis). Similarly, stiffness of the wild foods ranged from 1.15 MPa for Descolea sp. to 30.4 MPa for B. australis. However, the mechanical demands of accessing the kernels from within the shells (testae) of sandalwood and quandong (Santalum spp.) seeds far exceed measurements of any foods tested. We also tested some farmed foods, alongside inclusion of data from previous studies. Taken together, these data can also improve selection of comparable foods in designing diets for potoroids, and other species, in captivity.