Wars waged across the Galaxy as the great powers used their authority to purge all insectoid lifeforms, or at least those who were intelligent enough to travel between the stars. Of course, during this time, the great powers, aside from the Germanic Star-Empire, realized the folly of their ways.
The giant starships they had constructed to display their majesty, and to invoke a sense of intimidation, were all but useless against the Naraku Hive Fleets, whose small drones capable of flying through space, tore them to pieces, killing everyone inside them.
The losses which the four great powers who once went unchallenged across the Galaxy were substantial, losing most of their naval power during these conflicts. As for the Germanic Military, they focused their empire's might on the small fries.