Their larvae , called `` leatherjackets '' , `` leatherbacks '' , `` leatherback bugs '' or `` leatherjacket slugs '' , because of the way they move , consume roots -LRB- such as those of turf grass -RRB- and other vegetation , in some cases causing damage to plants .

They will sometimes `` wobble '' when flying . Crane fly larvae are called leatherjackets or ` leatherjacket slugs ' because of the way they move and eat roots -LRB- such as those of grass in lawns -RRB- and other vegetation .
