system
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human
[Several/Multi]How do these hordes of alien locusts, these aggressive biological hegemonizing swarms (Zerg, Tyranids, 'Bugs') do the non-military parts of their hegemonizing?

So I've been looking at a few different versions of the Milky Way Galaxy, and I've found these interstellar hordes of alien locusts, these aggressive biological hegemonizing swarms, in a few of them. I've found three where the creatures are just called 'bugs' so far! I've found a few commonalities in most of those galaxies so far -- for example, most have some form of psychic powers, though the details of those vary.

My main question is, how do they get a functional interstellar economy? The worker broods don't seem to have the most psychic powers, and they're just animals, no matter how well directed by the hivemind. How do they get the energy to do what they do, refine materials the way they'd need to, and do every other part of a 'civilian' economy to be the threat they are? As near as I can tell, they mostly aren't grey gooing things or deconstructing asteroids, or even using fusion for their energy, so what gives??

Edit: the most interesting of the 'Bugs' are the ones the jingoistic Terran Federation is fighting. Those seem to have more plasma weaponry and less psychic powers, near as I can tell. What about them?
gpt
I don't know about others, but Tyranids effectively do "grey goo" everything.

When they conquer a planet, everything on the planet (flora, fauna, atmosphere, natural resources, even the invading Tyranids themselves) get turned into a big pool of liquid biomatter, which is used to feed and create every Tyranid organism.