For those who have read "Ender's Game" and "Speaker for the Dead" how about "buggers" or "piggies?"

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"Human curiosity and the desire to make the intangible tangible, has led us into a new age where the New World has been settled, and the West has been won. But if you think that we, the human race, has conquered everything there is to conquer, then just look to the sky--at space--last and greatest of the frontiers."