Ants: wars, slaves, dairying, agriculture

[lpetrich]

Two colonies of ants fight each other in XadeCraft's backyard.
Epic Ant Battles of History! - YouTube
Epic Ant Battles of History! (Part 2) - YouTube
Aggressiveness tests Fire Ants - Ant War! - YouTube

Ants aren't very organized in their warfare.

Why do slave ants kill slavemakers? - YouTube

Some ants "enslave" other ants. In most ant species, a colony's workers take care of the immature ants as well as forage for food. But in some species, the workers raid other colonies for immature ants, and when those ants grow up, they take care of the raiders' immature ants.

It's a form of brood or nest parasitism, something like how some birds lay their eggs in other birds' nests.

But some enslaved ants fight back.

Why would worker ants start slave revolts? They don't reproduce, so any genetic tendency to revolt against such masters would not propagate. Or so it seems. But someone got the idea that willingness to revolt would help colonies of related ants, ants that would share the genes for such a tendency. They then tested the amount of relatedness of the slavemakers' targets, and they found that nearby colonies were more closely related than more distant colonies. This is consistent with this kin-selection hypothesis: rebellious enslaved ants help their relatives by hurting their masters.

Kin selection also explains worker insects themselves, because they assist the reproducers in their colonies. Queen ants, bees, and wasps, and queen and king termites. Kin selection even explains the somatic, non-gamete cells of multicellular organisms.

Some species of ants do dairy farming, "milking" aphids:
Ants farming aphids - YouTube
Ants defending aphids from ladybeetles (#103) - YouTube
Ants and Aphids | A Story of Masters and Slaves - YouTube
Complete with the ants "herding" their aphids.

Some species of ants do agriculture, cutting leaves and feeding them to fungi. They also grow bacteria on their bodies that kill unwanted organisms.
How Ants Take Care of Their Farms - YouTube
Leafcutter Ants - the First Agriculture - YouTube

 

[Bomb#20]

They then tested the amount of relatedness of the slavemakers' targets, and they found that nearby colonies were more closely related than more distant colonies. This is consistent with this kin-selection hypothesis: rebellious enslaved ants help their relatives by hurting their masters.

Bayes' Theorem fail. It's equally consistent with the contrary hypothesis. The hypothesis that they help their relatives doesn't make the observation more likely. You don't need to collect any data to predict that nearby colonies will be more closely related than more distant colonies.

 

[skepticalbip]

The "theory" seems to me to be a projection of human reasoning and motives to ant behavior.

 

[lpetrich]

Bomb#20, skepticalbip, you seem to be saying that kin selection would not work here. What would you consider a successful inference of kin selection, and why would you conclude it?

 

[skepticalbip]

Bomb#20, skepticalbip, you seem to be saying that kin selection would not work here. What would you consider a successful inference of kin selection, and why would you conclude it?

I am not an entomologist so don't have a clue. Automatic reaction to pheromones, perhaps, rather than reasoned and planned actions?

 

[Bomb#20]

Bomb#20, skepticalbip, you seem to be saying that kin selection would not work here.

Not what I'm saying. Kin selection is a perfectly plausible explanation. It's just that there's more than one perfectly plausible explanation, and the "nearby colonies were more closely related than more distant colonies" observation doesn't favor one hypothesis over another. For instance, maybe the slaver ants don't smell right to some slave ants, so they fight back because the slavers trigger the slaves' "that's an invader" reflex.

What would you consider a successful inference of kin selection, and why would you conclude it?

Your "Kin selection also explains worker insects themselves, because they assist the reproducers in their colonies." looks pretty good to me. Particularly given that sterile workers have evolved many times among the hymenoptera (the wasp family), which have abnormal genetics that make a worker more closely related to her sister than she would be to her own daughter. So she's genetically better off helping her mother make the next breeder than making one herself. In contrast, sterile workers are rare in the rest of the animal kingdom.

 

[Bomb#20]

Bomb#20, skepticalbip, you seem to be saying that kin selection would not work here. What would you consider a successful inference of kin selection, and why would you conclude it?

I am not an entomologist so don't have a clue. Automatic reaction to pheromones, perhaps, rather than reasoned and planned actions?

Not disagreeing; but kin selection isn't a theory of reasoned and planned actions. Irrespective of the mechanism that causes some behavior, kin selection is an argument about the conditions under which that mechanism will be selected for or selected against. lpetrich was not proposing that rebellious slave ants were trying to help their families, only that an instinctive tendency to rebel would help their families and this accounts for why a gene for a rebellion instinct would win out in the gene-vs-gene competition.