Prenolepis imparis (Winter Ant) Care Sheet

What is Prenolepis imparis?

​

Prenolepis imparis is the winter ant, also called the false honey ant or false honeypot ant. It's a small, shiny dark brown to black ant found across almost the entire continental United States, from southern Canada down into Mexico, from sea level up to around 8,000 feet (Cash et al. 2025). Queens tend to be brighter (often orangish) with darker workers.

​

What makes it remarkable is the calendar. This ant is active when nothing else is. In north Florida, foraging begins in November and ends in March or early April, at which point the workers seal the nest until the following November (Tschinkel 1987). Further north the pattern shifts, with colonies active through most of the year except the hottest summer months (Talbot 1943). Either way, the principle holds: while every other ant in the neighborhood is underground, these are out working, specifically when it's too cold for most other ants.

​

They forage at temperatures near freezing, which almost no other ant tolerates. It's a short list. Alongside imparis, the only well-documented cold-active ants are its European sister species Prenolepis nitens, and perhaps a few others.

​

Prenolepis imparis is also often the first ant in temperate North America to hold mating flights each year, which is why keepers who want one have to be watching in late winter/early spring while everyone else is waiting for June.

​

It should be noted that although the peak of activity tends to be in spring and fall, this species can still be active during warmer summer months, especially during night or colder weather. In general, though, they mostly stay underground during the summer, sitting at a deep enough depth underground to slow their metabolism.

​

How to identify Prenolepis imparis

​

Small, shiny, ranging from yellow to blackish, with a distinctly constricted waist between the mesosoma and gaster that gives them an hourglass look from above. Workers are 3mm and queens ~7mm. Pacific Coast populations tend to have darker queens, while eastern populations are still variable but mostly have lighter, orangish yellow queens.

​

This species used to have many 'variants', but these have not been in use for quite a while. Put simply, it can vary across its range in coloration, but as far as we know now, is considered one species. 

​

The thing everybody gets wrong about them

​

The common names are false honey ant and false honeypot ant, and both point at the same feature: colonies contain workers with hugely swollen gasters, which look exactly like the repletes in a honeypot ant colony.

​

For most of the twentieth century, that's what people thought they were. Wheeler (1930) and Talbot (1943) both described them as true repletes storing liquid food.

​

They aren't. Tschinkel (1987) worked out that the swelling isn't a distended crop full of liquid at all, but rather a  hypertrophied fat body. These workers are storing fat in their own tissue, not carrying a shared liquid larder. Over a winter of foraging, a worker's gaster becomes enormously corpulent and the ant doubles or triples its lean weight.

​

That distinction matters more than it sounds. A honeypot replete is a container the colony can draw from. A corpulent winter ant is a fat reserve, for the most part. It's the strategy that lets a colony sit sealed underground for an entire summer with minimal foraging.

​

Where is Prenolepis imparis found?

​

Almost everywhere in the continental US, plus southern Canada and parts of Mexico. Woodlands, suburbs, parks, and yards. They're one of the most common and widespread ants in North America (Cash et al. 2025) and most people have them in their yard without realizing it.

​

The nests are the remarkable part. Tschinkel (1987) excavated and cast imparis nests and found no chambers shallower than 60 centimeters, with tunnels reaching as far as 3.6 meters down. The colony is chasing cool, stable ground, and nests in Florida go deeper than nests in the north for exactly that reason.

​

Keep that in mind when you think about housing them. A species whose entire architecture is built around escaping heat is a species you probably shouldn't warm in captivity.

​

Their chemical weapon

​

Winter ants produce a defensive secretion from the Dufour's gland, an opaque white fluid containing a mixture of alkanes and alkenes. It's potent. In northern California, Prenolepis imparis is one of the few native ants that persists in areas invaded by the Argentine ant, and experimental work showed that the secretion often kills Argentine ant workers outright (Sorrells et al. 2011). Workers are more likely to deploy it near their own nest entrance than while foraging.

​

A native ant chemically holding the line against one of the world's worst invasive species is a good story, and it's true.

​

Is Prenolepis imparis good for beginners?

​

No, and not for the reasons people expect. They're not aggressive, they're not fragile in handling, and they don't need special equipment. They're difficult because they're slow, because the queens often suffer from SQDS (Sudden Queen Death Syndrome), and because colonies sometimes decline for no reason you can identify. More on that below.

​

Founding and the queen

​

Prenolepis imparis queens are fully-claustral.

​

Prenolepis imparis is polygynous, and colonies can hold multiple queens (Wheeler and Wheeler 1986; Tschinkel 1987). In most populations, you can keep queens together long term, and in some cases, they do much better in groups than on their own.

​

Mating flights are typically the earliest of any ant in temperate North America, usually late winter into early spring on the first warm days. In most of the eastern US, this is February or March, sometimes as late as April. It's the first warm spring day(s) that gets above 66-68F (ideally more than 70F). 

​

Growth rate and colony size

​

Slow, and they don't get huge. Mature wild colonies typically hold a few thousand workers (Wheeler and Wheeler 1986; Tschinkel 1987), which is small by comparison with most of what people keep.

​

Set your expectations accordingly. A keeper who is used to watching a Tetramorium or a Pheidole colony explode over one summer will find this species agonizing, so if you want to get them, keep in mind they're really a long-haul species not meant to be kept for a short time.

​

Some antkeepers do really well with growing the species out quickly. This seems to depend a lot on the queen, where she's from, and the keeper themselves. Some colonies are able to get many dozens of workers in the first year, but this is typically uncommon for most keepers.

​

Temperature: don't heat them

​

This is where the standard antkeeping advice does active harm.

​

Almost every care sheet you'll read, including the ones on this site, tells you to give a colony a warm end and a gradient. For Prenolepis imparis, forget that. This is a cold-adapted ant whose nests descend three meters into the ground specifically to stay cool. Heating them may stress them out.

​

For most of the time, it's perfectly fine to keep them at low room temperature (upper 60s or ~70F). This is what their near-surface chambers would be at much of the year. Unfortunately, there isn't a good way to replicate their chambers further underground, which may be much cooler than that most of the year.

​

Do Prenolepis imparis need to estivate?

​

In the wild, yes. Estivation is the summer equivalent of hibernation, and it's this species' defining seasonal behavior. In north Florida the workers seal the nest around April and don't reopen it until November (Tschinkel 1987). In the north, colonies stay active most of the year and shut down only for the summer (Talbot 1943). Personally, I've seen them active in the summer, just not nearly as much as spring and fall. In the fall, one of the most common sightings of this species is them enjoying a fallen, crushed or otherwise partly maimed apple. 

​

In captivity, in my experience, they typically don't need it. Keeping them at a stable temperature for most of the year aside from diapause is the right thing to do, considering they'd regulate this themselves in the wild. Keeping them at 80F in the summer, to estivate them, would be like forcing them to live only in the top few inches of the soil in the wild. They'd rather retreat to their deepest chambers, which hold a cool temperature. 

​

Feeding Prenolepis imparis

​

Generalist omnivores. In the wild they take insect prey, tend scale insects and other honeydew producers (Williams and Lucky 2017).

​

In captivity, I tend to feed them often, keeping as many of the workers fat as I possibly can. I don't overfeed sugars, so that workers are filling up on proteins and fats as well as sugars. Fruit flies, roaches, mealworms, all fair game. Sometimes, I offer a waxworm, since the fatty waxworm is loved by this species. Typical sugars work for them, sugarwater, Sunburst, etc.

​

Given their love for apple, small pieces could be offered. Make sure it wasn't treated and is washed thoroughly, as it can be risky.

​

Remove uneaten protein within 16 to 24 hours to avoid mold and mites.

​

Never feed wild-caught or house-caught insects. Pesticide residue kills colonies and you won't know why.

​

Why we don't sell Prenolepis imparis

​

Two reasons, and I'd rather tell you than have you find out after buying one.

​

They're slow. Growth is unhurried even under good conditions, and colonies stay small. For most keepers that means a year of watching very little happen, which is a bad first experience and a bad tenth experience.

​

They die for no clear reason. This is the bigger issue. In my experience, imparis colonies suffer random losses that don't trace to any husbandry mistake I can identify. A colony that looks healthy has their queen drop dead randomly, especially within the first few weeks, and even within the first year.

​

I sell ants I'm confident will do well for the person receiving them. This species doesn't clear that bar for me, and I'd rather lose the sale than send someone a colony I expect to fail in the short or long run.

​

Notably, some queens from certain areas seem to do better than others. 

​

If you catch one yourself, everything above applies, and I hope it goes better for you than it usually goes for some of us!

​

Common questions

​

Why are there ants outside in the winter? Almost certainly Prenolepis imparis, the winter ant, in temperate North America. It's active at temperatures where other ants can't function, foraging through the more mild cold months and sealing itself underground for much of the summer instead (Tschinkel 1987).

​

Are winter ants the same as honeypot ants? No. They're called false honey ants because they have workers with hugely swollen gasters that look like honeypot repletes. Tschinkel (1987) showed the swelling is stored fat in the worker's own tissue, not liquid food held in the crop. They're in a different genus than honeypot ants.

​

Do Prenolepis imparis need heat? No, and heating them is a mistake. They're cold-adapted, and their nests go up to 3.6 meters deep specifically to stay cool (Tschinkel 1987).

​

Do winter ants hibernate? Yes, in the coldest months, they're pretty much inactive. They estivate, too, in the summer, but this is not necessary to make in captivity. Diapause (hibernation) is necessary. For at least 2-3 months each winter, cool them to about 40F when repletes are well-fed. 

​

How big do Prenolepis imparis colonies get? Decently sized. A few thousand workers at maturity (Wheeler and Wheeler 1986; Tschinkel 1987).

​

Can Prenolepis imparis have multiple queens? Yes. Colonies are polygynous.

​

When do winter ants fly? Earlier than any other ant in temperate North America, on the first warm days of late winter or early spring.

​

Do winter ants sting? No. They have no sting, but they do produce a defensive chemical secretion that's effective enough to kill Argentine ant workers (Sorrells et al. 2011).

​

References

Cash, E.I., Ward, P.S., Escalona, M., Sahasrabudhe, R., Miller, C., Toffelmier, E., Fairbairn, C., Seligmann, W., Shaffer, H.B., and Tsutsui, N.D. (2025). Genome assembly of the winter ant, Prenolepis imparis. Journal of Heredity 116: 354-362.

​

Sorrells, T.R., Kuritzky, L.Y., Kauhanen, P.G., Fitzgerald, K., Sturgis, S.J., Chen, J., Dijamco, C.A., Basurto, K.N., and Gordon, D.M. (2011). Chemical defense by the native winter ant (Prenolepis imparis) against the invasive Argentine ant (Linepithema humile). PLoS ONE 6: e18717.

​

Talbot, M. (1943). Population studies of the ant Prenolepis imparis Say. Ecology 24: 31-44.

​

Tschinkel, W.R. (1987). Seasonal life history and nest architecture of a winter-active ant, Prenolepis imparis. Insectes Sociaux 34: 143-164.

​

Wheeler, G.C. and Wheeler, J. (1986). The Ants of Nevada. Natural History Museum of Los Angeles County.

​

Wheeler, W.M. (1930). The ant Prenolepis imparis Say. Annals of the Entomological Society of America 23: 1-26.

​

Williams, J.L. and Lucky, A. (2017). Winter ant, false honey ant, Prenolepis imparis (Say). University of Florida IFAS Featured Creatures EENY-675.

​

Related: All care sheets

​

If you want help identifying a winter queen you've caught, bring a photo to the Stateside Ants Discord.

​

If you're after a species that'll do better for a first colony, see what we have available.