This guide was compiled and written by Daniel Cantin of the 'Ants and Antkeeping' discord server, which can be found here. https://discord.gg/YbZGvtR3
This guide has been posted with the permission of the authors. The original article may be found here. I have also made some edits based on my own observations
caresheets/solenopsis_molesta - antkeeping (reddit.com)
Caresheet - Solenopsis molesta
Solenopsis molesta, also called as Northern Thief ants are known for ruining picnics. Their very small size makes them hard to locate but once you feel their unpleasant sting you’ll have no problem seeing them. Orginiating from the Southern States, they’ve made their way all the way up to Canada.
Taxonomy
Family: Formicidae
Subfamily: Myrmicinae
Tribus: Solenopsidini
Genus: Solenopsis
Species: Solenopsis molesta
Basic info
Origin: United States
Habitat: Enjoys warm temperatures and does sometimes require a heat pad for proper development.
Colony form: Mildly polygynous.
Colony size: 10.000+ workers
Colony age: 10-15 years
Founding: Fully claustral
Workers: Monomorphic
Nesting: They nest under rocks nests and dirt.
Hibernation: These ants require at least 1 month and a half of hibernation in 4-6 degrees celsius.
Reproduction: Nuptial flights throughout August.
Appearance
Workers: Workers are absolutely tiny. They are a very vibrant orange
Queen: They are small, have a orange body and have fluorescent yellow stripes on their gaster.
Drone: Black body and orange legs.
Size
Workers: 0.5-1.5mm
Queens: 2-3mm
Drones: around 1-2mm
Development time
at 75°F (24°C)
Egg to larvae: around 8 days
Larvae to pupa: around 10 days
Pupae to worker: Around 9 days
Egg to worker: 27 days
Ant keeping information
Recommendation: Intermediate level. Very small, they sting and it’s easy to lose track of them.
Temperature: 14-29° Celcius
Humidity: Outworld: room humidity, Nest: moist
Nest types: Nests in dirt and under stones. Also does great in test tubes and in acrylics (if kept moist).
Formicarium size: Should fit the current colony size. Grows fast and will need expansion after a while.
Formicaruim accessories: Heat source (optional).
Substrate type: ?
Behaviour
These ants are quite shy. They don’t leave the nest unless they want food and they’re absolutely tiny so they have a challenge foraging. They’re not very aggressive but if you do annoy them they’ll let their stringers take over. They are active during the day but I have also noticed them active at night as well.
Additional information
Solenopsis molesta are absolutely tiny which makes them very difficult to photograph. Their bright orange color makes them look amazing in acrylic nests.
They don't seem to be big foragers so I was able to keep them in a test tube until about 300 workers.
Solenopsis molesta love to borrow into the cotton which can result in them drowning themselves by breaching the water chamber and flooding the test tube. So make sure to keep an eye on that.
If you’re putting them into a natural set up, put your lighting outlet near the glass to produce heat and they will nest beside it. Also add a lots of rocks for them to nest under.
Diet
From what I’ve experienced Solenopsis molesta don’t seem to injust a lot of food. Possibly due to their small stature they don’t eat a lot of honey.
They seem to snack on protein once in awhile and possibly a sip of honey. I did notice however that they love pieces of chicken and bread.