Augmentation p154-155, talks about using literal swarms of bio insects and even gives one as an example. I think there's an error in the text, though. It says:
QUOTE
A swarm can split up into two smaller swarms with a Body rating one lower than the parent swarm, or four swarms with a Body rating 2 lower than the parent swarm, and so on. Similarly, two swarms of the same Body can merge to form a swarm one Body point larger. For simplicity’s sake, swarms that don’t possess the same Body merge into a swarm with the lesser of the two Body values.
Just before that, it says:
QUOTE
A swarm can split up into two smaller swarms with a Body rating one lower than the parent swarm, or four swarms with a Body rating 2 lower than the parent swarm, and so on.
So there's a direct correlation between size and Body. Now, a ginormous Body 9 swarm comes along and merges with a titchy small Body 2 swarm and the resulting swarm should have Body 2? No, it should have Body 9.