What do ants want? population growth, possibly: curiosity, much less signalling (in the way we know). Individual ants would work towards their queen's best interest? Would they try to defect to other queens?
Digging (foundations of new houses and such) would be a bad idea.
Ants would naturally have a slow communication rate.
Ants could communicate faster than walking by flying, putting their pheramones in the air somehow, using human internet, using human intermediaries.
Ants can increase their population quickly. I would rough guess doubling every month at least for the first month
Ant main-line cognition speed would be slower than humans, but multitasking greater. Therefore they would likely execute multiple plans at once instead of making one big plan.
Ants would look for technologies to enhance their cognition even further. Could be dense, 3d habitats that allow the colony to live closer to eachother to reduce transmission time.
Increasing speed of individual ants. I don't think ants tend to travel at even half of their max speed, so they could think faster by just burning more energy in a way humans can't.
Ants are everywhere. Some humans would try to escape ants by fleeing to cold places with permanently frozen soil, like northern Canada. Because of their small size, ants have extreme difficulty in those conditions. Ants couldn't go there without vehicles.
Given that ants primarily sense touch and smell, they may still lack good eyesignt and hearing, even with better communication. This means they may be hard for them to read computer screens and eavesdrop on humans. For example, I doubt a single ant could spy on a computer screen. Perhaps 100 or more ants would be required for that. Same with hearing, although it would be easy for 1000 ants to hide within earshot of human conversations.
Therefore humans may communicate more by text to hide from ant spies.
How would ants fight against poison? My guess is by just attacking until poison is used up.
Humans need to prepare for war with ants before they show signs of aggression. They could be too powerful for humans to stop.
Ant colonies would begin communicating with each other. An ant can travel at perhaps 3km/hour. Assuming this is their mode of communication, somewhere like the Amazon would take like a year to send a message across. I don't think it's reasonable for ants to first-contact "native" ants through a faster means, just because they wouldn't be able to decode it.
Would ants resent humans for often carelessly killing their kind? They may not consider worker deaths very important, but human activities would definately "anger" (anthropomorphizing) the ants before most humans knew ants were smart.
Creating supersmart supercolonies. I think this is reasonable, but linear processing speed would again be slower the more space the colony took up. Because of the speed limitation, it would take a long time before we have to worry about a global coordinated attack.
How would ants and humans communicate? By sound. Human microphones and software would detect ant vibrations, and ants would either learn to understand human speach, or hear ant noises produced by translation software. Probably the latter, because humans have vastly more expertise than ants.
Individual ants live around 2 years, queens up to 30. Intelligent ants would merge colonies whose queen dies, or produce extra queens to keep colonies alive. "individual" ant colonies could outlive humans.
Would ants war with other ant species (more than they already do). I think it's likely the first thing that'll happen. Bigger colonies, with more intelligence, would quickly kill off smaller ant colonies.
Which ants would win the ant-wars? Depending on how ant intelligence works, either smaller ants that can get closer together, or larger ants with more complex behavior, would come out ahead. Large ants could have advantages like better eyesight, wings, that become vastly more useful with intelligence.
Ants would destroy their predators and overeat their food. Much like humans, who killed off large mammals, ants would kill off all their predators and risk over-harvasting their food. They would start both farming and stealing from humans as well.
Ant predators include spiders, other insects, reptiles, and amphibians. This would cause some sort of ecosystem collapse.
Eventual ant technologies: ant computer interface, may be like a braile display that pokes different individual ants, or ant sould based. Because ant colonies would be good at multitasking, they could absorb material faster than human, given that it's not all highly connected.
Human would publish this, be highly questioned. Would produce simple tests individuals could make at home and give to ants to get idea through to people.
Govts would probably put up a far worse performance than COVID. Politicians & beaurocrats are too old, too social to deal with this kind of stuff.
Immediately some young right-ists would call for the eradication of ants. It would take a few weeks for right politicians to follow suit, at least pushing for "safety against ants"
People would buy tons of bogus "ant communication devices" or "ant protection devices"
There must already be ant colonies in secure scientific experiments. They would be studied. New colonies would be taken into labs.
How much do ant colonies work with each other? Given that there are already ant-mega-colonies (their main trait is they "smell like friends" of each other), those ants would work together. They would likely work together with "smells like enemies" ants as well. I don't expect average ant colonies to sacrifice for each other immediately, but maybe later?
Can ant colonies "mind meld" with each other? Given that the colonies themselves started working together intellectually a week ago, I think it's likely they could.
Ant cognition speed is the #1 variable to measure.
Humans might engineer ant-to-ant comms devices to prevent ant wars, make ants more predictable, and spy. All ants using bugged (get it) comms would be awesome.
Food left out in human homes would be quickly taken by ants. Ants would quickly bite through fridge seals and eat there too. Ants could use leverage to open alumanum cans and plastic boxes.
People would find ways to make ant poison at home
Humans would disrupt ant hearing and smell with ant-verbalization noise generators or some homemade chemical that confuses or dulls ants' senses.
Mosquitos developed resistance to DDT in "about 7 years". Ants different reproduction. Because of investment in queens, they can't experement genetically with them. Would need to test ant males. Could test males for pesticide resistance before mating, accelerating that evolution. ant males never go outside normally, so that would improve a lot.
There are roughly as many ant colonies as humans, so some EAs would immediately help ants. For short-termists, ants would likely be #1 priority by far. First would give comms and teach.
Evangelical Christians would attempt to convert ants. I would ROFL soooo hard if that actually worked.
Once ants learn the basics of human infrastructure and society but before they invent their own technology, what's their best bet to defeat humanity? There are on the order of a million ants per person. I'm guessing that they wouldn't be able to overpower humans just by swarming and biting except in very rural locations. If they did, they would strike at night. They can be silent, so you may 100,000 ants in your room without waking you up. They could suffocate you with their bodies, or with some tools. I think suffocating people at night with cloth/bodies would work. Even better, they could cut wires in cars / short circuit them, and swarm power plants / relay centers. Perhaps gnaw down trees to fall on power lines. Given the time taken to get power back after storms, and especially the Puerto Rico disaster, I'm not optimistic we could ever regain the grid. Again, I think they would take a while to coordinate that well, but we would need to secure the grid FAST.
Ants would hop onto cars, trains, boats, and eventually planes to explore & communicate with each other. Ants communicating this way may be able to jump off cars in large enough numbers to communicate, especially at lights & stop signs. Otherwise get off at the destination, talk to local ants, then all move out on new cars. This would be the fastest means of ant communication. Travel times from london to any inhabited place in the world are around 1/2 to 1 day. Ants would require maybe 4 extra hours to crawl between people & vehicles in airports and such. Some areas don't have enough car traffic to easily hitch a ride to, so that might cost an extra day if they aren't able to call taxis or manipulate humans into driving places or whatever. It would be reasonable for them to get 1-2 day global communication by physical transport.