So, you’ve caught a queen ant—nice work! The first few weeks (or months) are the most delicate for a founding queen, so a good test tube setup is one of the best gifts you can give her. It’s cheap, low‑stress and, when done right, reliably mimics the humid, dark chamber queens prefer in the wild.
This guide keeps the familiar step‑by‑step format but adds the practical detail many Australian keepers ask for: precise tube sizes and water volumes, cotton types and packing technique, temperature and humidity targets, sterilisation and mould‑prevention steps, timelines for founding, plus a short primer on claustral vs semi‑claustral queens with examples of common Australian genera. There are also photos/diagrams, a printable checklist and a quick reference table to make setup fast and repeatable.
1. Quick primer: claustral vs semi‑claustral queens (and why it matters)
Before you build anything, know whether your queen is claustral or semi‑claustral—this changes what she needs in a test tube.
- Claustral queens seal themselves off and raise their first brood using only their body reserves. They usually won’t accept food while founding and prefer a totally sealed, humid chamber. Common genera that are often claustral in Australia: Monomorium, many Iridomyrmex and some Pheidole.
- Semi‑claustral queens need to forage or be provided with food while the brood is developing. They often prefer an outworld or a loose connection to forage. Typical semi‑claustral examples in Australia (behaviour can vary by species): Myrmecia (bull ants) and some Camponotus. If you have one of these, give her easier access to food and consider an outworld.
Note: behaviour varies between species. When in doubt, assume the queen may need food and be prepared to provide a small, safe outworld. If you’re unsure what species you’ve caught or want a reminder of good beginner options, see our Best Australian Ant Species for Beginners.
2. Equipment checklist (buy or gather before you catch a queen)
- Glass test tubes (150 mm length × 16–20 mm diameter are ideal) — several so you can rotate/replace tubes without disturbing the queen. If using plastic tubes, keep them for short term only.
- Sterile cotton wool or dental cotton rolls (lint‑free). Avoid coloured or perfumed cotton.
- Distilled water (or tap water left uncovered for 24 hours).
- Small pipette or syringe to add/remove water cleanly.
- Parafilm or laboratory film (optional) to slow evaporation at the open end.
- Black paper or aluminium foil (to darken the nest) and sticky tape/labels.
- Thermometer (and hygrometer if you can) for monitoring temperature and humidity.
- Small forceps, magnifier/loupe and a tray for safe handling.
- An outworld (small plastic container with a hole that fits the test tube opening) if you expect a semi‑claustral queen.
Printable quick checklist
Tip: press Ctrl/Cmd+P to print this section only for your field kit.
- Glass tube 150×16–20 mm (x3)
- Sterile cotton (dental rolls)
- Distilled water (small bottle)
- Pipette or 1 mL syringe
- Parafilm or tape, black paper/foil
- Forceps, loupe, labels + pen
- Small spare outworld (if semi‑claustral)
3. Test tube sizes and exact water volumes (quick reference)
Recommended tube: 150 mm length × 16–20 mm inner diameter. That gives enough room for a water reservoir, cotton barrier and a dry chamber for the queen.
Water volume rule of thumb: fill roughly one‑third of the tube by length. For a 150 mm tube that’s ~45–55 mm of water. In practical terms that’s about 8–16 mL depending on diameter (see table).
| Tube inside diameter | Water length (approx) | Water volume (approx) | Wet cotton plug length (mm) | Dry cotton plug length (mm) | Queen chamber length (mm) |
|---|---|---|---|---|---|
| 12 mm (narrow) | 45–50 mm | ~6 mL | 12–20 | 20–25 | 60–75 |
| 16 mm (common) | 45–50 mm | ~8–11 mL | 15–25 | 20–30 | 60–75 |
| 18 mm (common) | 45–50 mm | ~10–13 mL | 18–30 | 20–35 | 55–70 |
| 20 mm (wide) | 45–50 mm | ~13–16 mL | 20–35 | 25–40 | 50–70 |
These are practical approximations so you don’t have to weigh water precisely in the field. The most important things are that the wet plug contacts the water and that the queen chamber remains dry and roomy enough for the queen to turn around.
4. Cotton type and packing technique (the small details that matter)
Use sterile, lint‑free cotton or dental cotton rolls (available from chemists or hobby suppliers). Avoid fluffy craft cotton that leaves fibres everywhere.
Step by step:
- Add your water (8–12 mL for a 150 mm × 16–18 mm tube). Use a pipette or small syringe to be neat.
- Take a compact plug of cotton and push it firmly into the tube so it contacts the water. This is the wet plug that wicks moisture up but keeps the water contained. It should be tight enough to stop free water movement, but not so tight that the cotton is rock solid—capillary action needs to work.
- Leave about 20–35 mm of clear space for the queen’s chamber (this is where she’ll sit and lay eggs). That’s roughly 2–3 cm of empty space between the wet plug and the open end.
- Seal the open end with a second, dry cotton plug. This should be firm enough to stop escapes but not completely block airflow; or use a small plug plus a wrap of parafilm for controlled ventilation.
Do not pack the cotton so tight that the queen can’t turn around—she needs a little room. If you can, keep the queen’s chamber dim by wrapping black paper or foil around the tube (leave a small window to check on her without disturbing).
5. Where to store the tube: temperature & humidity targets
General target conditions for most Australian species:
- Temperature: 22–28°C for temperate species. Tropical species may prefer 25–30°C. Avoid sudden temperature swings or direct sunlight.
- Relative humidity: aim for ~60–80% in the storage area. The test tube creates its own local humidity, but keeping the surrounding air too dry speeds evaporation and increases failure risk.
Practical storage: a dark drawer, cupboard, shoe box or specialised humidity box. If you need heat, use a low‑output heat mat with a thermostat set to the target temperature rather than plugging a mat straight into the wall. For larger projects or to stabilise multiple tubes, see our guide on upgrading and building humidity boxes for long‑term stability.
6. Sterilisation, cleaning and tube rotation
Prevention is better than rescue. Mould and bacteria are the most common causes of founding failure.
- Glass tubes: boil for 10 minutes or place in an oven at 120°C for 20–30 minutes. Let cool and handle with clean hands.
- Plastic tubes: avoid high heat. Wipe with 70% isopropyl alcohol and rinse thoroughly with boiled (then cooled) or distilled water. Replace plastic tubes frequently — they’re harder to sterilise completely.
- Cotton: use new sterile cotton every time. Don’t reuse cotton that’s touched the ground, roof dust or your fingers.
- Tools & bench: wipe forceps and trays with 70% isopropyl alcohol between uses. Wash hands or wear gloves.
Tube change intervals: don’t disturb the queen unnecessarily. Move her to a fresh tube if:
- Water has nearly disappeared or is leaking.
- Mould is visible and spreading towards the queen.
- There’s visible contamination (mites, fungal spores) or the cotton has been tainted by food.
When you do move her, do it with minimal light and disturbance: place the old tube next to the new one inside a dark container and let the queen relocate herself if she’s willing. For a full, step‑by‑step transfer method, read Moving Your Queen Ant from the Founding Stage to a Formicarium and our shorter Move a Queen Ant to a New Test Tube guide.
7. Troubleshooting: mould, evaporation and rejections
Mould growth
Signs: white, grey or green fuzzy patches on cotton or glass.
Prevention & fixes:
- Use distilled water and sterile cotton.
- Avoid adding food in the tube. Food is a mould buffet.
- If mould appears away from the queen, prepare a fresh tube and transfer the queen as quickly and gently as possible. If the mould is limited to the far end, you can sometimes remove and replace the outer dry cotton and wrap in parafilm to slow humidity spikes.
- Keep ambient RH moderate—too high and mould thrives, too low and water evaporates too quickly.
Rapid evaporation
Signs: cotton plug dries out, water level drops significantly in one or two weeks.
Fixes:
- Pack the wet cotton a little tighter next time but keep capillary action working.
- Wrap the open end with parafilm or connect the open end to a small sealed humidity chamber (e.g. a sealed box with a damp paper towel) to slow evaporation.
- Store the tube in a more humid spot (not in the sun or near heaters).
Queen rejects the setup
Some queens (often semi‑claustral) won’t settle in a fully closed tube. Try these options:
- Darken the tube (black paper or foil) so it looks more like a natural chamber.
- Offer a tiny outworld: pop the test tube into a small container with a secure lid and a tiny entrance so she can leave to forage for small insects or honey solution.
- If she’s clearly agitated and won’t settle after 24–48 hours, she may have been recently stressed. Give her a quiet, stable environment and try again with a fresh tube.
8. Timelines for the founding stages (rough ranges)
Every species is different and temperature accelerates or slows development. These are typical ranges at ~22–26°C:
- Egg → larva: 1–3 weeks.
- Larva → pupa: 2–5 weeks.
- Pupa → first workers (nanitics): typically 4–12 weeks total from egg, often 6–10 weeks for many temperate species.
Notes: higher temperatures speed development (but not too high—don’t exceed species preferences). Tropical species may develop faster; cold‑adapted species slower. Keep records (date of capture, egg dates) so you know when to expect workers. When nanitics arrive, our guide on moving to a formicarium has step‑by‑step photos.
9. When and how to move the queen to a new setup or outworld
Move the colony when:
- The first workers (nanitics) are present and active: they’ll need foraging space.
- The tube is mouldy, leaking, or the water has run out and a quick transfer is necessary.
- The colony is physically filling the tube—ants touching both ends, or the queen/workers bumping the cotton frequently.
Gentle transfer method:
- Prepare the fresh tube/formicarium and darken it.
- Place the old tube and the new tube close together inside a dark box or drawer, with the openings near each other. If you’re moving to an outworld, make a small tunnel between them using a short length of tubing.
- Leave them for a day or two—the ants will often move on their own when they’re ready.
- If they don’t move, you can gently coax them with light tapping or by easing the cotton back slightly so they can explore the new connection, but keep disturbance minimal.
10. Useful extras and clever tricks
- Label tubes with date of capture and species (or location) so you can track development.
- Keep a spare ready: it’s faster and less stressful to move a queen to a prepared tube than to rebuild one under pressure.
- Use a loupe or phone macro lens for quiet checks—bright lights upset queens.
- For long term founding (several months), consider a humidity box or a sealed tub with damp substrate to stabilise ambient humidity.
11. Legal and ethical collecting reminder (Australia)
Quick note: collecting queens during nuptial flights is common, but be aware of local regulations. Some reserves, parks or private land require permission. Don’t remove queens from protected species or from areas where collecting is prohibited. If you’re unsure, ask local authorities or join a regional myrmecology group for guidance.
Where to next?
Read these next for species‑specific tips and the next stages:
- Best Australian Ant Species for Beginners — to pick an easier species if you’re new.
- What to Do with a Queen Ant After Capture — handling and immediate steps after capture.
- Moving Your Queen Ant from the Founding Stage to a Formicarium — step‑by‑step transfer methods for when nanitics arrive.
- Preventing Mites: How to Keep Your Ants Safe from Infestations — prevention and treatment basics.
- Upgrading Your Ant Colony’s Formicarium — when and how to move beyond test tubes.
FAQ (quick answers)
How often should I check the tube?
Keep checks to a minimum: once every 5–7 days is fine while the queen is claustral. Use a loupe or phone macro to peek through a small window rather than unwrapping the whole tube.
Can I reuse cotton or tubes?
Glass tubes are reusable if thoroughly sterilised. Cotton should be replaced each time — it’s cheap and reusing cotton increases mould risk.
What if the queen drowns?
Drowning usually happens when water sloshes into the queen chamber or cotton packing fails. Prepare spare tubes and keep movements gentle; if you must add water, do it slowly with a pipette and check the wet plug seating.
When should I offer food?
Claustral queens won’t usually eat while founding. Semi‑claustral queens need small amounts of protein and sugar; offer food in a secure outworld, not inside the tube. If unsure, check species notes or our handling guide linked above.
Conclusion
A well‑built test tube setup is one of the simplest, highest‑impact things you can do for a founding queen. Get the tube size and water volume roughly right, use sterile cotton, keep temperatures steady and humidity moderate, and don’t poke the queen unless you must. With patience and a couple of backup tubes, you’ll give her the best possible start.
Get the small details right and soon you’ll be watching those tiny first workers — one of the best moments in ant‑keeping. Happy founding! 🐜
