Brachyponera chinensis Species Introduction
Treat her as semi-claustral and offer small prey from the start, since an unfed ponerine queen is the more expensive mistake. Colony structure is the unusual part: facultatively polygynous, polydomous, and in one Japanese survey 266 of 400 nests held no queen at all. Workers have no ovaries, so a queenless fragment cannot raise a replacement.
Native to Japan, Korea, China and Taiwan and south into Vietnam and Thailand, and carried to the southeastern United States from Japan in the early 1930s, where it went almost unnoticed for fifty years. It differs from every other invasive ant in walking into undisturbed hardwood forest rather than settling for roadsides, and where it establishes it outnumbers every native species combined. In North Carolina plots it cut Aphaenogaster rudis workers by 96% and seed removal by 70%. Nests sit in rotting wood, leaf litter and soil under stones and logs, stay small, and spread across several sites that are often queenless. It is a termite specialist. It does not establish where Reticulitermes is absent, takes them five times more often than anything else within reach, and has never been recorded feeding on nectar or honeydew. No trail pheromones either. A scout that finds food walks home and carries one nestmate back to it, then returns to the nest empty in 93% of observations. Workers run about 3.5mm, shiny dark brown with lighter orange-brown legs and antennal tips.
Not a beginner ant, and not one to take on casually at all. The sting is the reason. In its native range 2.1% of people stung went into anaphylaxis, which is a different order of risk from anything else in the collection, and this is also a serious invasive that establishes in intact forest. What goes wrong here is rarely the colony. It is a lid left off, or a keeper who reached in. Settle the containment and the sting plan before the ants arrive.
Formicarium
A humid gypsum or substrate nest suits them, since the wild nest is rotting wood or damp soil under a stone. Containment is the whole job. Keep the outworld lidded, run a fluon barrier on every vertical surface, seal each tubing joint, and check the seams before you open anything. Move ants with an aspirator or a cup, never with fingers.
Water & Humidity
Humid. The wild nest is rotting wood or damp soil beneath a stone or a log, on shaded forest floor rather than open ground, and foragers come out more on cloudy days than on sunny ones. Keep most of the nest damp with one drier corner, and give them substrate rather than bare acrylic where the setup allows it.
Recommended to use TrapJaw Labs PVA sponges during founding for improved success rates and more nanitics. Keep the tube damp throughout, as this is a species that never wants a dry nest.
Keep a liquid feeder with water (distilled, purified, or spring) in the foraging area at all times. Ponerines often ignore feeders, so a pebble-filled water tray is a useful backup, and a properly damp nest does most of the work anyway.
Protein
Protein is effectively the whole diet. This is a termite specialist that does not establish where Reticulitermes is absent and takes them five times more often than anything else within reach. Feed heavily, two to three times a week and more while brood is heavy. Recruitment is slow, so leave items down long enough for a scout to find one and go back for help rather than clearing them on a formicine's schedule.
TrapJaw Labs feeds our B. chinensis colonies with pre-killed D. melanogaster and D. hydei fruit flies, cockroach nymphs, and sliced mealworms. Termites are the item this species is built around, and a colony offered them will work them hard, so keep a culture if you can do it legally and safely where you live.
Two to three times per week. Increase amounts to scale with brood development.
Carbohydrates
This is the rare species where sugar may not matter. Brachyponera chinensis has never been recorded taking nectar or hemipteran honeydew in the wild, which is the trait that most separates it from other invasive ants, though wild workers do take the juice of decayed fruit off the ground. Offer sugar-water anyway, as a captive diet is not a wild one and it costs nothing. Judge the colony on how it takes protein.
Occasional small honey drop in the outworld is fine. Do not read an untouched drop as a sick colony, because indifference to sugar is the normal condition here.
Optional, and they will often ignore it. Keep water available regardless, and never use the sugar level as your read on colony health.
Maintenance
Weeks 1-3: Settle her somewhere dark and undisturbed, and offer small prey items from the start rather than sealing her in and waiting. Deliver food without moving or inspecting the tube. Keep the sponge wet throughout.
Weeks 4–6: First workers ('nanitics') appear. Offer small pre-killed items two to three times a week and leave them down, since recruitment here runs on one worker carrying one other worker to the food rather than on a trail. Growth is slow next to a formicine of the same age. That is normal for the subfamily and not a sign anything is wrong.
Months 2+: Steady growth that stays slow, with the colony spreading across whatever nest space it is given. Move them up at about 75% of the nest space in use, and add a second nest rather than one large chamber, as this is a polydomous species that will work both. Do not split a colony to make two, because a queenless nest has no route back.
Diapause may be required for this species. Brachyponera chinensis runs from temperate Japan and Korea down into the tropics, and the United States population came from Japan, so what a colony needs follows where it was collected rather than the species. Southeastern US stock should get 8–10 weeks from late November at 50–60°F. Remove supplemental heat but keep water sources fully-stocked and the nest damp, and keep offering small protein items. This species goes cold later and wakes earlier than most of what we keep.
Care Summary
- The sting is medically significant, do NOT keep this species around anyone with an insect-sting allergy
- Lidded outworld, current fluon, every joint sealed, aspirator not fingers
- Protein is the whole diet, 2–3×/week and more with brood
- Termites are the natural prey and sugar is close to optional
- Humid nest with substrate, shaded rather than brightly lit
- Never split a colony, a queenless nest cannot raise a new queen