Alright, had some time to take a look at these guys again. Had to re-run the sim with the parents and their offspring all together. It seems the parasites will only begin to tie when they're already tied to other bots. I think it's controled by nrg amounts, so when the bots receive nrg from other sharefeeding bots, they will begin to fire ties themselves. At first the Parents lead, but over time their decendents take over, eventually wiping out the parent species that got them started.
I think it's being done to keep the bots from wasting nrg by tieing to low nrg siblings. Not a problem I would have thought of, that's for sure.