The nation
of locusts is described as "powerful". The description notes their teeth as lion-like and their fangs as those of a lioness. The meaning is that the locusts, despite their small size, are as great destroyers and exterminators as the king of the animal kingdom.1
6 For a nation has come up against my land, powerful and beyond number; its teeth are lions’ teeth, and it has the fangs of a lioness.