[bduerst]

Right, but do the ants practice animal husbandry? Do predatory fish eat the lazy skunk shrimp to ween the herd?

I think the point they were trying to make is that there is no other sapient symbiotic relationships, but there are few sapient species so it's kind of moot.

[Nadya]

Animals are far smarter than humans give them credit for [1]. That isn't to say any species comes close to the broad scope of human intellect - but to say that there are not purposeful interactions of survival among other species would be wrong. That is why I said I did not know of one offhand, rather than say they do not exist. Although I could not name one on a level higher than bacteria, I knew it was likely to exist.

Symbiotic relationships are not quite the same - again with my definition arguably being arbitrary. I consider a symbiotic relationship to be when two animals happen to benefit from each other due to their actions and it is not one species using another.

That is the case for most symbiotic relationships I can think of. For example, pilot fish and sharks. Sharks happen to host bacteria that the pilot fish eat. Eating the bacteria is obviously beneficial for the pilot fish and happens to benefit the shark as well. It's not that the pilot fish specifically chose sharks to eat bacteria from. This appears to be happenstance.

Some of the examples of ants and aphids seems to be happenstance. The ants defend an aphid from another creature that eats/destroys the aphids so that the ants can eat it. That's fighting to protect their food source - something I consider "necessary for survival" and not "beneficial for survival".

The case I cited where the ants will harvest the aphid eggs, store them safely for the winter, then bring them back to plants to hatch is along the lines of "beneficial for survival". It's an intentional use of aphids as a food source with what appears to be a methodology of breeding and sustaining their honeydew food source. It's a "step above" a symbiotic relationship in my eyes. [2]

[1] http://www.cell.com/current-biology/abstract/S0960-9822%2814...

[2] Again, I recognize that where I'm drawing my line might be arbitrary to some people. I hope I explained how I see some of the scenarios as different to one another in a way that other people can understand where I stand. If not, please ask questions.