Waterbug are one of the two stronger soldier drones. Although waterbugs aren't nearly as powerful as normal drones, and have weak weapons, they have semi-good melee attack accuracy. They are normally seen protecting patches of marsh and the drones inside that area.
Waterbugs are the strongest in defenses, but have very weak attack power compared to other drones. In the endgame, the waterbug becomes the least threatening drone despite most probably being intended to be the most powerful. Even mosquitos are more threatening because they can fly to areas where fragile flying units are otherwise unprotected and striders can hurt a little with their cannons.