Hi there. I'm planning to make a small nid army based around
FMC's and Spore mines (Biovores, Harpies etc.).
I believe hive Fleet Jormungandr would suit my theme: a Hive fleet that disdains headlong charges and wars of attrition. I also like the colour scheme which is a plus.
The thing is, Jormungandr seems to mainly use burrowing creatures to strike behind the lines.
Therefore my request for help is for any ideas as to why a Jormungandr splinter would switch, from the burrowing tactics, to striking from the skies and using long range bombardment.
My own potential ideas so far (I'm not quite happy with these) -
1. They encountered Imperial Worlds that used a lot of artillery, and the subsequent barrages killed any organisms below the surface with the concussive forces. Leading the Fleet to adapt by mostly leaving the ground or hiding units out of sight and returning fire.
2. They came across a group of worlds unsuitable for burrowing (massive plateaus of solid granite etc.) and adapted to circumvent defences through other means; flying and bombardment to remove
AA.
3. They came across worlds with high numbers of flyers and their burrowing units were unable to harm said flyers. That way they adapted to engage the flyers on their own terms and brought biovores etc. to harass fliers on the ground and to make airfields unusable.
Any ideas that could make this work? I've been wracking my brain trying to come up with something I really like

Thanks in advance.