Biomechanical components of the plant-insect herbivore arms race: A model test in leaf-cutter ants

Insects and plants have been locked in an evolutionary arms race spanning 350 million years and whilst much work focuses on the chemical components of this ancient contest, mechanical aspects remain largely understudied. We test a simple biomechanical model that relates the force required to cut thin leaf-like tissues to their mechanical properties, and the geometry of the cutting tool. To remove confounding effects of tool shape across size, we utilise leaf-cutter ant mandibles as a model system, who are also both an economically and ecologically relevant pest species. We measured the force required to cut both natural and pseudoleaves across mandible sizes (mass) and wear states (using pristine vs worn mandibles) using a custom built setup based on a fibre optic force sensor. To quantify the geometry of the cutting edge we measured the mandible cutting edge radius and wedge angle using focused ion-beam milling (FIB) and scanning electron microscopy (SEM). The results substantially sup..., , # Biomechanical components of the plant-insect herbivore arms race: A model test in leaf-cutter ants

Dataset DOI: [10.5061/dryad.r2280gbqh](10.5061/dryad.r2280gbqh)

## Description of the data and file structure

We have submitted all data presented within the manuscript, including the average steady-state cutting, fracture, and spacing forces for the pseudoleaf force dataset (Pseudoleaf_forces.csv). The thickness corrected average steady state cutting, fracture, and spacing forces for the natural leaf force dataset (Leaves_forces.csv). The mandible cutting edge radius measurements were taken at varying percentages of total tooth height, measured in ImageJ (FIB_SEM_Radius.csv), and the mandible cutting edge wedge angle was also taken at each tooth height obtained in ImageJ (FIB_SEM_Angle.csv).

### Files and variables

#### File: FIB\_SEM\_Radius.csv

**Description:** 

Cutting-edge radius and wedge angle were obtained using focused ion-beam milling (FIB) and scanning electron microsco...,