Formica subsericeaSpecies Introduction
Claustral. A newly-mated queen seals itself in a chamber and raises the first workers entirely on stored nutrients and metabolized wing muscles, with no food needed until the first workers are running. Founding is typically pleometrotic — several queens will co-found — and mature colonies may retain more than one egg-laying queen.
Native to eastern North America, from southern Canada south through the eastern and midwestern states. Most often found in open woodland, woodland edges and clearings, nesting in soil beneath stones and logs. Colonies may be monogynous or polygynous. Formica subsericea is also one of the most important host species in eastern North America — Formica pergandei, Formica densiventris and Polyergus mexicanus all raid it — so look closely at any field-caught queen before assuming a straightforward subsericea.
High-energy and forgiving of most mistakes, but not of a skipped winter. Give them space, keep the protein coming, and run a real diapause, and they are one of the more straightforward large Formica to keep.
Formicarium
Soil or substrate nests suit this ground-nesting species, and they will readily excavate. Give them ample space, as established colonies build quickly. A secure nest and a fluon barrier on the outworld are recommended.
Water & Humidity
Most of the nest should be relatively humid, with this being a soil-nesting species. They do prefer having access to drier, warmer conditions where the pupae can be kept.
Recommended to use TrapJaw Labs PVA sponges for founding due to improved humidity.
Keep a liquid feeder with water (distilled, purified, or spring) in the foraging area at all times.
Protein
Protein is important for these ants but is a smaller component of their diet than carbohydrates.
TrapJaw Labs feeds our F. subsericea colonies with pre-killed Drosophila melanogaster and D. hydei fruit flies, cockroach nymphs, and sliced mealworms.
Once per week.
Carbohydrates
Sufficient access to carbohydrates is critical for this species.
We recommend providing our Honeydew Honey once a week. It replicates the micronutrient profile of the carbohydrate sources that these ants feed on in the wild (aphid honeydew and extrafloral nectar). Please note that honey-water is not suitable for use in liquid feeders and should only be provided in feeding dishes or on top of sliced, organic apple.
We recommend providing sugar-water (we use our Ant Nectar Mix) and fresh-water liquid feeders in the outworld at all times.
Maintenance
Week 1: Settle the founding queen or queens somewhere dark and undisturbed. Stress from disturbance can cause a queen to consume the brood, so avoid checking on the colony during this process. If founding in a test tube with a TJL sponge, humidity and water will be maintained throughout this process.
Weeks 4–6: First workers ('nanitics') appear. Put out a stocked sugar feeder; offer a small protein item (a few fruit flies or mealworm sections) about once a week. Population climbs slowly, that's normal.
Months 2+: Maintain humidity and liquid feeders 24/7. Protein remains a small item, provided weekly. Consider a larger humid nest upgrade and more outworld space as the colony begins to utilize 75% of the nest space; optional supplemental heating speeds growth (but don't overdo it).
Diapause is required for this species. Do not go by the calendar — watch the colony. Begin when larvae hold at first instar and stop developing, brood production ceases, and foraging drops off. Northern stock should get 12–16 weeks at 40–50°F; southern stock is satisfied with 6–8 weeks or less. Keep liquid food and water sources fully stocked throughout, and do not allow the colony to freeze.
Care Summary
- Obligate diapause — trigger on stalled brood, not a date
- Humid nest environment
- Liquid feeders kept full
- Room temp works; a gradient of 72–82°F with a genuinely cool end