Special organ on abdomen (gaster) produces vibrations (e.g., Markl 1965; Tautz et al. 1995; Roces and Hölldobler 1996; Wirth et al. 2003; Hölldobler and Wilson 2009; Hölldobler and Wilson 2011, and as noted)
Scraping structure rubs against a file-like structure
Increases leaf-cutting efficiency (Tautz et al. 1995)
Vibrations transferred to the leaf reduce force and energy needed to cut plant material
Vibrations summon help from nestmates, in tandem with pheromones (Roces and Hölldobler 1995; Hölldobler and Wilson 2009; Hölldobler and Wilson 2011, and as noted)
Recruit nestmates to food resources and possibly for nest building
Recruit small minim workers to hitchhike on leaves to defend larger foragers against parasitic flies