Supplementary data for "Reducing the risk of rostral bending failure" Author summary: Weevils are among the most diverse and evolutionarily successful animal lineages on Earth. Their success is driven in part by a structure called the rostrum, which gives weevil heads a characteristic "snout-like" appearance. Nut weevils in the genus Curculio use the rostrum to drill holes into developing fruits and nuts, into which they deposit their eggs. During oviposition this exceedingly slender structure is bent into a straightened configuration - in some species up to 90° - but does not suffer any damage during this process. Using finite element models of the rostra of three morphologically distinct species, we show that the Curculio rostrum is only able to withstand repeated, extreme bending because of modifications to the composite structure of the cuticle in the rostral apex. This is the first time that the laminate profile, orthotropic behavior, and functional gradation of the cuticle have been incorporated into a three-dimensional finite element model of an insect cuticular structure. Our models highlight the significance of biomechanical constraint - i.e., avoidance of catastrophic structural failure - on the evolution of insect morphology. Finite element models of Curculio rostra. FE model databases, job files, and output databases containing imported part geometries, meshes, and fully-specified material models of the head and rostrum for each species; full dataset available here. File names indicate species, mesh size (s02 is the finest model scale), load condition (either in mg for validation models or bending for prescribed displacement models), and which modifications have been removed from the layup (i.e., layer thicknesses or orientation angles - or both - are set equal to those of the head capsule). Files for a single species should all be placed into a single folder after unzipping. The abaqus plugins folder (with material definitions) and the .cae/.jnl files (.cae is used to open all the models in Abaqus CAE) should be in the same folder with the rest of the model files. The sulcatulus folder shows this organization, the models for other species had to be separated due to file size constraints. X-ray tomography data. JPEG image stack and 3D reconstruction from µ-CT scan of female Curculio caryae; full dataset available here.