Hooray! I can write again!
I've been working on a new sort of Eco sim. It uses a couple of different bots set in a pond like enviroment. So far the two bots I have living uncivily [you]together[/you] are a ground body feeder, and an energy feeding semi-fixed tier.
The plant I made doesn't use buoyancy to float, instead it orients itself sunward by turning then accelerates upward. It is can also instead randomly sink to the ground at birth. This forms a sort of loop with veggies rising and falling. (The upward acceleration required also cause the veggies to exhaust their nrg supplies and subsequently become corpses which feed the lower bots.)
The tier can then attach to the veggies and rise up to the top left hand side(why I don't know, maybe they like it there :) ). Once there they fix themselves and reproduce babies that promptly unfix allowing them to fall until they get their own veggies.
The body eater below eats bots, corpses and occasional falling plant. Even though it's is stronger than the tier, the lack of a tieing ability keeps them relativly seperated.
I'll post the settings and bots when I get back to Hawaii. I still have some work to do on the tiers, since I'm still having to direct them somewhat at the start. I'd also like to figure out a third niche for a species, but so far I'm only seeing the two.