Children of Ruin by Adrian Tchaikovsky (Children of Time #2)

 It has waited through the ages now it's time.

Thousands of years ago, Earth's terraforming program took to the stars. On the world they called Nod, scientists discovered alien life - but it was their mission to overwrite it with the memory of Earth. Then humanity's greatest empire fell, and the program's decisions were lost to time. 

Aeons later, humanity and its new spider allies detected fragmentary radio signals between the stars. They dispatched an exploration vessel, hoping to find cousins from Old Earth. However, those ancient terraformers woke something on Nod that was better left undisturbed. And it's been waiting for them.

A book by author Adrian Tchaikovsky.