The Replicators mod allows the Locusts to replicate by alt-firing on the ground nearby. Also: Lowers DPS: 100 -> 50. Lowers HP: 80 -> 50, so 1 shot by Sparks. Reduces speed: 40 -> 34. They're countered quite well by T1 bombers, Dox, and of course any of the Titans Available on PAMM.
It would also be impossible, unless that damage was "upon death", which would be cool, since you could make a weaker version of the replicator that split on death like that.
You can spawn a unit upon the death of another. So it's only possible as in, based on how much damage the locust receives. As long as you have a set of 'different' units that prevent an infinite loop. EDIT: wait, if the unit does AOE damage but to itself as well, then it could in theory sorta seem to work in that fashion...
Updated to v1.1. Locusts now have to "reload" before firing, so you can't infinitely duplicate. Removed HP degeneration. DPS back up to 50 (still half of vanilla).