I wonder if there is experimental evidence on this (either from computer simulations or perhaps cases of isolated species like on the Galapagos Islands).
Imagine the hypothetical situation of a group of individuals of the same species that becomes isolated from all others. I know it's not a very realistic scenario because life is pretty much everywhere on Earth, but maybe experiments could be done in the laboratory.
So we have, for example, 100 or 1,000 or so individuals of the same species (any species, from any domain and kingdom of life) that is isolated from all other life. I know this group would undergo several speciation events (I think I've read about experiments like this and I think it's not really debatable, but is likely to be universally agreed upon by evolutionary biologists), but would this group eventually evolve natural enemies (e.g. a predator-prey or host-parasite or similar relationship)?
I think limited resources would certainly result in different competitors evolving, with some competitors fitter than others, but I'm not sure about enemies. I'm thinking that given adequate time, full-blown enemies would be almost certain to evolve, but that's just a guess.
A more specific example might be to take a single ant colony or honeybee colony and isolate it in a laboratory and study it over hundreds of generations or more.
I did some searching on this, but didn't find anything closely related to this question.
For more context, I started thinking about this question while reading this article.
Thanks in advance for any thoughts on this.
Edit: assume in a lab experiment that non-living nutritional sources (e.g. sugar water) were supplied in a measured way.