Theres already an alge called Flyfruit, wich channels the Fruitflies DNA as a virus and infects whatever is near (It also has some random viruses and is capable of icorporating new viruses in it's arsenal, should it get infected by someone). This way it can spread as an alge, but the infected bots won't have a population cap from being veggies.
I should also mention that Quickdraw won't perform too well as an alge... not unless the alge pop cap is fairly high.
Anyway Flyfruit 0.92 was the last version where the alge and the infected bots worked together (Meaning the alge would feed the infected bots if they had the same dna length as the original virus)
But it was mainly made because EricL issued the 9000 bots on IM challenge (Only reached 7000 before EricL disabled viruses from alge in his sims)
However the thing isn't very interesting... it just freezes the sim once a bot is infected by the Fruitfly virus (Dynamic costs can have other outcomes, but eventualy the sims gets booring fast). Also promissed not to release it again and was personaly plagued by it reapearing from old sims via the intra sim teleporter (Keep me off IM till now, so not about to run it again)
This is also the reason why it's hard to spread normal Fruitflies on IM, because your own sim will freeze fast, and even if you keep the pop down the flies that get teleported only have a small chance of making it on their own. (An everage fruitfly is size 1 and holds no more than 100 nrg... hard to invade a sim with that)
I'm actualy trying to mess around with the original fruitflies atm, just set the artifitial pop cap to 150 (Instead of 1000 from the F1 league, just change the value of maxpop in the bots code) and gave it some lower mutation rates... But so far I've had to restart the sim 4-5 times, since the only evolutionary step it seems to be interested in is the mutation breaking the population cap (Which freezes the sim).
Currently running the sim with very low mutation rates, and so far the pop cap still hasn't been broken, but I fear it's only a matter of time, it takes only one mutation and is very benefitial so sooner or later it'll happen again. But so far it seems to be coexisting with Webfungus... it's funny how dorcile fruitflies are when the pop cap is very low (Using 150 as maxpop in a size 2 sim).
The only reason Fruitflies seem to be agressive is because the F1 version has a high pop cap, so they're everywhere, feeding on everything. Without the high numbers they barely seem to be doing anything, I think theres 300 fruitflies in the sim (Pop cap is loose but get's hard once you reach twice the pop cap) and Webfungus is doing just fine (I even have a pig in there, although I doubt it'll last much longer).