How could had leaf-cutter ants evolved "fungus farming"?

Question

The leaf-cutter ants of the Amazonian Basin are unique in that they survive through their special form of agriculture of ant-fungus mutualism, where they actively cultivate, fertilize, remove weeds, and harvest fungus for food and even build their nests so that they can control the humidity and carbon dioxide level through sophisticated tunnel designs. The wrong humidity can kill off the fungus and allowing the carbon dioxide from the growing fungus to built up can suffocate the entire nest. Pretty amazing if you ask me.

But here's the question that's been bothering me; how could these ants had evolved ALL THIS if we were to follow Darwin's theory of evolution. I mean, ants can't pass down knowledge like us humans (cultural transmission). They have to rely on the programming from the genes that were passed to them in the egg.

But how could the genes that allow them to successfully conduct their agriculture have came to be in the first place? Farming crops, especially ant fungus, is a complex activity. Miss one step and you won't have an harvest and at worst you'll starve. Even if the leaf-cutter's ancestors managed to somehow randomly developed one step in growing some wild fungus in their nest, that one step wouldn't bring in a harvest without somehow the other dozen other steps coming to be at the same time. Hence, that one random genetic coding won't had any detriment effect on the survivability of that ant and propagating the "farming" gene into the niche specie we see today. Also, lets not forget that its female ant drones who do all the work in a colony, but how could a mutated drone that has the random genetic programming to cultivate fungus pass on her genes seeing how she is sterile? Darwin's theory just doesn't seem to fit in this case. Its like the "1/6th off a wing" paradox. How could random mutation had evolved ALL these steps to turn an ancient ant into a leaf-cutter ant? Is Darwin's theory wrong?

Please be aware that I am not a Creationist. I prefer Darwin's theory of evolution, but this question has me in doubt. Could intelligence by design be somehow true in this case? I will appreciate it if someone can lend me their thoughts on this!

Answer 1

It's not unreasonable for the relationship to have developed in a stepwise manner. The evolution of complex social and colonial life almost certainly occurred in the ants' ancestors prior to the evolution of fungus cultivation, so only some minor, sequential tweaking would be necessary to produce a colony conducive to raising fungus. Furthermore, not all of it need be genetic. Ants may not possess the same degree of cultural sophistication that we do, but they aren't mindless automatons.



I can actually envisage the ancestors of modern leaf-cutter ants possessing almost all the tools necessary to harvest fungus full-time. Being able to properly vent a colony of carbon dioxide and bring in fresh oxygen is necessary for all types of ants; fungus may boost the oxygen use and carbon dioxide output of a colony, but ants do this anyway without sharing living quarters with fungus. So really, you'd just need to add a few more openings to the surface, something that doesn't need rigid genetic programming. Ants change the architecture of their colonies to meet their needs all the time. Too much carbon dioxide? Build another vent using behaviors that already exist.



Harvesting isn't that much different either. Ants harvest food to begin with; the only difference here is that this food source is now within the colony, and the foraging behavior is now modified to collect leaves and grasses to feed the fungus. Again, pre-existing behaviors modified to suit a new task.



I couldn't tell you that this is what happened, of course, but hopefully it will get you thinking like an evolutionary biologist. If you just think about what ants could already do and what pressures they would have been under, your mind can run wild for hours with evolutionary possibilities. Just because some structure or behavior is complex doesn't mean it couldn't have evolved. Coevolution is especially good at shaping organisms; just think about flowers and all the different, specific organisms that pollinate them. The selective pressure imposed by the ants on the fungus is arguably more obvious and fascinating, but the fungus exerts its own selective pressure back on the ants; it relies on the ants for food and reproduction, so the ants don't just get a free ride.



Lastly, keep in mind that the ant-fungus relationship probably wasn't always obligate. I would imagine it started off as an antagonistic relationship, with ancestral ants simply eating ancestral fungus out in the wild. Only over time did it become mutualistic and obligate.

Answer 2

Coevolution

Answer 3

Liberals take advantage of the good nature of people, they're parasitic. Any Ants are more noble than liberals.