Macro–micro synergistic mechanisms of Curculio rostrum against buckling

Slender biological structures, which are widely observed in nature, exhibit exceptional properties and biological functions. A notable example is the Curculio rostrum that can drill into fruits for feeding and egg-laying without buckling. However, it remains unknown how the slender and curved Curculio rostrum resists buckling. In this article, we propose an elastic rod model for the rostrum that has multi-layered microstructures reinforced by helical chitin fibres. Its buckling behaviour is inve