How to Diapause (Hibernate) an Ant Colony

Diapause is one of the most misunderstood parts of antkeeping in the U.S., and it’s also one of the biggest reasons colonies fail long-term. When done correctly, diapause extends queen lifespan, keeps your colony healthy, and establishes brood cycles. When done poorly (or skipped when it’s required), colonies often stall, crash, or slowly decline for reasons that aren’t obvious until it’s too late. For some species, especially in the north, diapause is extremely important. 

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This guide is meant to give you a general idea about diapause, not a one-size-fits-all program. Ants are diverse, and every species is different. If diapause is necessary for your species, the specifics of their diapause will be noted on their product page on Stateside Ants!

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Diapause vs. Hibernation (what the words actually mean)

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These terms get used interchangeably, but biologically they are not the same thing.

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Hibernation

• A state of deep metabolic shutdown

• Common in mammals (bears, squirrels)

• Body systems dramatically slow, sometimes near dormancy

• Ants do not truly hibernate

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Diapause​​

• Metabolism slows, but does not stop completely!

• Common in insects

• Development (especially brood development) pauses

• Triggered by seasonal (but also internal) cues, like temperature and an internal clock.

• Ants remain alive, responsive, and capable of basic activity

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So when we talk about “ant hibernation,” what we actually mean is diapause — a process similar to hibernation that ants use to survive the winter. 

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Which ants need diapause?

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It's important to understand that there is no one-size-fits-all for diapause in ants. Each genus and, indeed, species, can be very different. We'll provide general advice below, but check into your individual species for specifics.

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Quick Notes:

• Many temperate North American ant species require diapause

• Ants that experience cold winters in the wild evolved expecting a winter rest

• Skipping diapause when it’s required can lead to:

  • queens stopping egg-laying

  • brood not growing (or being eaten)

  • shortened queen lifespan

  • colonies that fail a year or two later for unclear reasons (just overall collapse)

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However, it's also important to keep in mind that there are some species perfectly able to skip diapause (and that might even thrive from it). Examples include Tetramorium immigrans, Pheidole bicarinata, Pogonomyrmex occidentalis, and many more. Those are species that, in most of their range, would have a diapause naturally, but in captivity can skip it altogether with little to no bad effects in the medium-term.

 

Although large extended studies about skipping diapause (in these species) have not been done, there have been very old, healthy colonies that never underwent diapause.

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For some species, especially species in southern areas (like Florida) diapause could be very detrimental, especially if done wrong. Most southern ants can withstand short cold periods, but if done incorrectly (too long, too cold, too dry, etc.), it could harm your colony. It's always necessary to check for your species in specific.

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How to Diapause (Temperature)

For most temperate U.S. ants, a cold diapause works well.

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General recommended diapause range: 36–42°F (2–5.5°C)

This range is safe for the majority of temperate North American species.

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​It's important to remember, though, that some species prefer a warmer diapause (in the 40s), especially if they're from the south. ​Never freeze your ants! If they get below 32°F, they could freeze to death.

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However, if the ants get too warm, their metabolism may inevitably become active and starvation could come sooner. This is why it's recommended to not diapause most ants above the 40s. 

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Cooldown And Warmup Periods (Strongly Recommended)

In nature, ants don’t go from summer to winter overnight. Abrupt temperature changes can stress colonies.

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Ideally:

Pre-diapause:

Cool down (place in a cooler-than-room temperature area) for 1-2 weeks at least. Slow feeding.

After diapause:

Warmup (place in a warmer-than-fridge temperature area) for 1-2 weeks at least. Don't feed right away unless they're starving, but after a day or a couple days, start feeding in tiny amounts. 

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This strategy helps to mimic the natural weather patterns ants experience. Throwing a colony into the fridge without warning could cause them harm, which makes it very important to do a small cooldown period. The warmup period is less crucial, but still undoubtedly beneficial (your ants won't start growing again right away, so you might as well let them ease into it). 

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The cool thing is that you don't need to have an area that goes down by 2.5F every day. You can use steps like this:

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Room temperature → cool room/basement → fridge

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Fridge → cool room → room temperature

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Even if you can’t change the temperature by a few degrees each day, having an in-between stage is usually enough to tell the ants "Hey, diapause is coming!". They'll perform the needed hormonal and chemical changes in their body.

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How Long Should Diapause Last?

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Diapause should ideally last for 3-4 months, but this also varies depending on species. Most Camponotus and Lasius species do best with 3-4 months. Some ants, like some Formica or Crematogaster, can do less, often 2-3 months instead. 

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Where do I Diapause my Ants?

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Your best option is usually a wine cooler or a fridge. It's recommended not to rely on the appliance thermometer, and instead have your own right by where the ants are diapausing. Put them in a place they won't be bumped as much, especially in a tube, as flooding can be common with cold temperature and shaking/rolling!

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Keeping Ants Hydrated During Diapause 

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It's extremely important that your ants are well-hydrated during diapause. Although they don't need feeding during diapause, they do need moisture, or the ants will desiccate. 

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Many water-tower or acrylic hydration nests won't completely cut it during diapause. It's a good idea to hook up a test tube setup in the weeks before diapausing your ants, allowing them to move in and use it as last resort during diapause. There have been many occasions when a colony is diapaused with a nest and a test tube setup, and the ants in the nest have high death rates, while the test tube ants suffer many less casualties.

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The only issue with test tubes in diapause is that they could flood when bumped or, more commonly, when taken out of diapause. When you take your ants out of diapause, make sure to keep an eye on them for the next 4-8 hours or so. Water may creep out from the hydration blocker, just barely flooding. When this happens, using a pipette/syringe to suck the water out. Do this until it stops leaking, which is usually pretty quickly. 

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If you cannot use a pipette or syringe to do this, you could pour sand onto the blocker. Try to avoid covering ants or their brood in sand, but in general, having some sand on the ants is better than having the ants underwater. If necessary, remove the ants manually. 

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Still have questions about diapause in ants?

 

We encourage you to join our Discord (linked here)! There, you can interact with both experienced and new antkeepers, getting advice, ideas, and encouragement!

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