Board Thread:Warhammer 40k General Discussion/@comment-7186329-20130329201743/@comment-6078851-20130502142636

if tyranids are lured by volume of bio-mass then dead worlds in their path could be seeded with ork spores. by dead world i mean no life but a breathable (to orks at least) atmosphere. as the orkoid species are a completely self contained ecosystem, and rapidly reproductive, then it wouldn't be long before a world gained the attention of a hive fleet.

as for what to do once said attention is gained, while the imperium (and most races actually) are loathe to destroy viable worlds, to cause significant damage to the tyranid race will need never before used measures - i still favour the celestial orrery as the single best weapon against tyranids (distance and the shadow in the warp would not a factor), and while it's use (even in the most favourable conditions) will require millenia of micromanagment to prevent a galactic collapse - those would be millenia in which the tyranids, if they survived, would be a fraction of the threat they are now. the hive mind might even be diminished to the point where the shadow in the warp has no influence, which is one of the biggest advantages of tyranids.