That was what they were here for. They being the aliens and here being earth. They lived off of spirit matter and the aliens had saved themselves by finding and harvesting the spirit matter from earth.
On their home world, some aliens confessed to a guilty conscience over the living conditions of the humans and having robbed them of their spirit matter, but the symbiotic relationship — namely longer life for humans (which they seemed to want), and succulent, aged spirit matter for the aliens — always overcame any concerns about ill treatment of the homo sapien livestock.
The breeding had been slow; some types did and others did not survive or breed well. Even today, some could breed and reproduce better than others. During the days of the early earth species, when there was still near starvation on the home world, there was little spirit matter for the gatherers to collect and rush home with. For thousands of years they could barely keep their civilization alive. But then the alien innovators on earth created the super humans who could breed like rabbits, and since then, the home world has had all the food it needs. This was the time of plenty. Until now.
The God and Goddess of earthly stardust were too peaceful, too loving and could not lift a finger to stop the aliens – but they and the world still had their free will. But the alien starving electric beams of other-matter, the lost space of unmatter, had to survive; they also came out of the infinity of light and not-light cosmos.
The aliens kidnapped the goddess and held her for ransom, and in exchange for her life, the aliens got the earth spirit matter. They did not care about mineral rights, they did not need or want the trees or the water. They had demanded and gotten control of the insects as they assisted with the clean-up of the earth matter after the spirit matter was collected, at death.
The goddess screamed and screamed through the spirit waves for all to come to her, rather than mature to an edible age. But she could only be heard by the god and not the humans. The god loved his goddess too much to sacrifice her for the humans. But the goddess wanted to save all her spirit matters. The goddess had been able to reach a few of them in the mind’s eye and taught them how to go to space and how to self destruct with nukes, but she could not convey why this would be such a wonderful way to go. Then all the spirit matters of earth, and all that had ever lived would be saved from the angry aliens. All spirit matters would be flying together, to coalesce into a new perfect world where all love each other – no more light and dark, no more white and black, or cream and brown. All a lovely sparkling shimmer of uncolor.
The aliens had out foxed themselves; the very technology that made the species flourish for the bountiful harvests was also the means to wipe them out. If too many humans died at once and life support broke down, there would be a stall in food production and this could stop the prosperity of the home world. But the aliens were sure they could keep the self destructors at bay as they had handled food crises in the past. The population explosion would continue.
The flaw the aliens had been able to exploit was over the manner of spirit matter death. It was simple, die in joy and there is long enough of a window to seek out god and goddess and fly to the stars. Die in meanness and hate, and the aliens can gobble you up whole, the second the breath of spirit life leaves the earthly body. Before the aliens had found their earth food supply of spirit matter, the spirits had had time to sort out angry and loving. But once the angry aliens took over, one needs to choose love. Openly take a stand to stand for love on earth.
The mother goddess, although kidnapped, was still able to embrace the beauty of each spirit matter in her heart and give each one her blessing of eternity, if each one could just get through the light one last time. The hearers of the goddess seemed to know the truth and tried to spread the word – when it is time, take your own path for love.
But, the war in the plasma of stardust was diverting the spirit matter through violent angry death. Those lost spirits became the food of the un-gods, the aliens.
Time and again the god tried to tell his peoples, your god and your mother goddess are love. But the aliens got all the world fighting to get ahead, and then they ate the rest.
The alien agents of doom spread the hate until humans succumbed and hated. They became no more than earthly roadkill, their spirit matter consumed.

A roadkill squirrel near a driveway in Boise, Idaho. CC BY-SA 3.0
File:FlatSquirrel.jpg Created: 3 November 2012
https://en.wikipedia.org/wiki/Roadkill
I have written about how much I LOVE Google. I need to write about Wikipedia love also.
Googleology ~ I Love Google! Google, Google, Google!