Peters suggestion is a good one. High light and thick fluids along with higher costs in the prey sim I would say. And very low light and low costs in the predator sim (Maybe have some basic alge which repopulates in the predator sim). And well, something in between in the sim in between.
This should prevent either specie from being wiped out and keep an ongoing battle for the ground in the middle.
Or at least it'll increase the chances.
You should be aware that any specie can evolve using chloroplast though. So the predator could start using chloroplast and invade the prey sim eventually.
On a side note. Made 2 bots and tested them a bit. They seem to be able to coexist. But like peter mentions, the bigger the sim the better and the more bots the better. Also you can't actually cap the amount of bots really, so you need to tweak things like light and costs, which could just end up wiping out one specie.
One important thing, if you plan to try out Peters idea (And I think you should), then be aware that the predator of these 2 bots I'm posting is using chloroplast, but a small amount. (You could simply adjust light settings so the small amount the predator uses isn't enough, or you could just remode that from the code.)
Anyway here are the bots. I added some constant values at the top of each you can use to tweak. But things like maxpop tend to break very easily I'm afraid. Never took long before the population just exploded and sim speed went down to 0.1 cylce per sec.
(You should expect it'll take 1-2K cycles before sim starts to get going)
Prey:
def maxpop 1500
def maxchlryoung 300
def maxchlrold 1000
def childpct 20
def reprosize 3000
cond
*.robage 30 <=
start
.deltie inc
.mkchlr inc
*.nrg 50 >
100 .sx store
stop
cond
*.robage 30 >
*.nrg 100 <= or
*.totalmyspecies 150 <= or
*.nrg 10 > and
start
*.chlr .maxchlryoung <
dupbool
*.nrg 100 > and
100 .mkchlr store
dropbool
.mkchlr inc
*.chlr .maxchlrold <
*.nrg 100 > and
*.robage 1000 > and
100 .mkchlr store
*.nrg 500 >
*.body 1000 < and
*.nrg 5 div 100 floor .strbody store
*.shflav 0 !=
*.body .reprosize > or
*.numties 1 >
*.nrg 100 >
*.body 300 > or and or
*.totalmyspecies 150 < or
300 rnd .aimsx store
100 .dx store
0 .shflav store
.deltie inc
dupbool
*.timer 50 mod 0 != and
*.totalmyspecies .maxpop < and
.childpct .repro store
dropbool
*.timer 50 mod 0 = and
*.totalmyspecies .maxpop < and
.childpct .mrepro store
stop
Predator:
(Consider removing chloroplast from it, basically take out any part with .mkchlr)
def maxpop 1000
def childpct 30
cond
*.nrg 50 >
*.robage 100 < or
start
60 .sharenrg store
*.robage 0 =
450 .eye5width store
.eye5width .memloc store
.robage .tmemloc store
*.body 400 >
*.eye5 0 <=
*.body 700 > or and
*.totalmyspecies .maxpop < and
500 rnd .aimsx store
dupbool
*.timer 50 mod 0 != and
.childpct .repro store
dropbool
*.timer 50 mod 0 = and
.childpct .mrepro store
*.nrg 500 >
*.body 1000 < and
100 .strbody store
*.nrg 300 <
*.body 100 > and
100 .fdbody store
*.chlr 100 <
.mkchlr inc
*.eye5 0 >
*.memval 450 != and
*.refvelup 50 *.eye5 sub 0 floor add .up store
*.refveldx .dx store
*.refxpos *.refypos angle .setaim store
.tie inc
dupbool
*.refbody *.refnrg > and
*.tmemval 500 > and
-6 .shoot store
dropbool
dupbool
*.refbody *.refnrg <= and
*.tmemval 500 > and
.shoot dec
dropbool
not
30 60 rnd sub .aimsx store
30 .up store
.deltie inc
stop
The sim I ran was rather large (Over half way on the slider), with 1/8 mutation, started spawning 200 prey and 50 predators. Light settings are tricky, seems to work with either just 80 light, or 300 light per kilo veggy.
Biggest issue here is that there's a manually added maxpop in the code and this will break fast and end up freezing your sim eventually.
You may want to remove it or set it higher and then try to control population through environment settings instead, tweaking light and costs slightly.
Remember that when tweaking settings you should change them slightly and then give it lots of time to take effect before tweaking again, or you 'll suddenly have wiped the sim.
In any case good luck, and I second Peters idea. I think it's your best option.
I should also mention that when I made these 2 I simply had one large sim in mind. I think Peters idea is better, so if you want I can try to set that up myself and make some modifications to made the bots more suited for that purpose. (Unless you want to adjust them yourself)