Nor Crystal Tears

Before Man and insect like Thranx had become allies, when the reptilian AAnn were just occasional raiders of Thranx colony worlds, one young Thranx agricultural expert lived a life of quiet desperation.
A dreamer in a world of sensible, stable beings, Ryo buried himself in his work -- reclaiming marshland from a tenacious jungle -- until he came across a letter describing a relative's encounter with horrid, two-legged, soft-skinned space-going beasts . . .