No solitary ants have been described by scientific journals. If they had, they would be a famous exception, their ecology and survival strategy would be very interesting, to know how they rear their broods. It is mostly nectar and parasitism that makes Hymenoptera broods easy to manage alone.
velvet ants are solitary and resemble ants but they are actually wingless wasps.
Meranoplus primitive old world ants are the most likely to have solitary species, and have simpler clades, i.e. no queen, all workers may lay eggs.
Carpenter ants are solitary you will see one queen in a house full of termites and other ants that live in colonies
I have spent 35 years remodeling homes infested with termites and ants the carpenter ants which are huge are never seen tohether
The queen finds termites and other smaller types of ants
She will stuff these other ants and termits into a tunnel made by the wood chewers and lay an egg and seal the tunnel
The larva hatches and eats the food left
Pupates and digs its way out of the tunnel it then either gets pregnant or looks for a mate if male
Eating the infesting ants and termites
In 35 years of remodeling and construction with many many homes torn apart i have never seen more then 1 carpenter ants at a time
There are smaller black ants people mistake for the larger cousins but ants that actually tunnel in wood are not carpenter ants
Carpenter ants invade their food's tunnels and feed them to the eggs which they abandon after sealing them into thier egg tunnels which were made by the termites or other ants
Ants are canibals by nature and eat other type of ants
Carpenter are no exception to this rule