Medflies

The members of the Terran agricultural colony Olympus, on a planet distant from Earth, have found themselves at odds with the native race of the planet, huge beings that look like nothing so much as piles of rock. After fifty years the Terrans had assumed the Natives were friendly or at least neutral. Now, all of a sudden, they have become hostile. To the surprise of the Terrans, the Natives have an advanced technology that they are using to eliminate the colony. Their actions remind the Terrans of the reaction of Terran scientists to the Medflies of Earth many centuries ago, only on this planet the Terrans are the Medflies. They must find a way to overcome the Natives' hostility and the results of their technology, which have effectively sterilized all the Terran women. They must also try to do this without hurting the Natives too badly--and especially without destroying them--because only they can undo the sterilization. The task of the colonists is prohibitively difficult. Is it even possible?