Original: Their larvae , called '' leatherjackets '' , '' leatherbacks '' , '' leatherback bugs '' or '' leatherjacket slugs '' , because of the way they move , consume roots ( such as those of turf grass ) and other vegetation , in some cases causing damage to plants .
Simplified: Crane fly larvae are called leatherjackets or ` leatherjacket slugs ' because of the way they move and eat roots ( such as those of grass in lawns ) and other vegetation .