Western Harvester Ants (Pogonomyrmex occidentalis) Care Guide (Care Sheet)
My name is Anthony Prothero, and I'm the founder of Stateside Ants. I've been an antkeeper for over a decade, and throughout that time, I've kept plenty of Pogonomyrmex occidentalis colonies!
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Pogonomyrmex occidentalis is the only ant species that has been federally deregulated in the lower 48 of the United States by the USDA. Western Harvester Ants are some of the easiest ants to keep, and some of the most entertaining! The only main drawback is that this ant can sting, but as long as you don't plan on handling them, that shouldn't be an issue. They're poor climbers and therefore escapes are extremely rare. In this sheet, we'll detail all the care info you need to keep Pogonomyrmex occidentalis healthy and growing!
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Short Sheet
Queen size: 7-9mm.
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Worker size: ~4-7mm.
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Founding method: Fully-claustral, but benefits strongly from seeds in founding. Needs heat in founding.
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Egg-worker times: Around 25-35 days, if fed and heated sufficiently.
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Polygynous?: No, typically monogynous.
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Ideal temperature: 90-95°F
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Humidity: 85-90%+ in part of the nest. Lower in much of it.
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Hibernation temperature: 40°F, but hibernation is completely optional. Heat and continue feeding, and the colony will continue to grow.
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Protein preference: Very generalist. This species loves fish flakes but will also eat insect protein, and should for the health of the queen.
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Carbohydrate preference: Seeds. They can take liquid sugars, but it's unnecessary and can cause issues. The best seeds tend to be Kentucky Bluegrass, Dandelion, and many more. Our seed mix has a huge variety!
About the Queen
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The average Pogonomyrmex occidentalis queen is a beautiful orange queen anywhere from 7-9mm in length. They're fully-claustral, but ideally they should have some seeds in their tube during founding!
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This species must be heated in founding. Without heat, this species will not grow.
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This species is typically monogynous. This means that only one queen is found per colony. Queens can found a colony together, but typically fight after workers hatch. For this reason, do not combine queens!
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About Growth
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Pogonomyrmex occidentalis can grow extremely fast when heated and fed sufficiently. Accustomed to high heat, the brood can be incubated and grown to maturity in just a few weeks after the egg is laid. Most colonies can reach thousands of workers in the first year on the high end! On average, a colony would have 200-500 workers within the first year if heated and fed regularly. The colonies can reach more than 10,000 workers within the first few years of colony growth.
Temperature and Setup
Pogonomyrmex occidentalis benefits highly from heat and cannot grow normally without it. During founding, the temperature (at least in the front of the tube) should be 85-90°F. Once the colony continues to grow and they're moved into a nest, part of the nest should be above 95F. This hot part of the nest can incubate the brood. Allow a part of the nest to be cooler and somewhere in the 80s. If you're heating a test tube, only heat the front, not near the water reservoir, as this can cause floods.
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While keeping their nest warm, it's equally (or more) important to maintain humidity in the nest. In a test tube, humidity is generally stable as long as the water reservoir hasn't completely dried. In a nest, there should always be evaporating water to create humidity, and preferably a direct source of drinking water too. If you aren't sure, keep a test tube setup attached to the nest as a failsafe. If the ants run out of water without you noticing, they'll pile in the test tube, and that will be your sign.
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Remember not to move ants into a nest that's too large! You should be able to imagine your current colony filling at least half of the nest before you move them in. If they aren't big enough, grow them out in their current nest until they fit. If it's becoming difficult to feed them in the tube, use a Tubs and Tubes setup!
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Keep your colony's foraging area clean. Seed casings and insect exoskeletons in P. occidentalis colonies can be ripe breeding grounds for mold and mites, especially if there's moisture! Clear out trash piles often.
Feeding
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Pogonomyrmex occidentalis aren't hard to feed! They're primarily harvester ants, meaning they can live almost entirely off of seeds. It's a good idea to feed them protein every now and then for the larvae and the health of the queen, but technically, they can live without it!
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It's not recommended to feed large seeds that the ants have difficulty handling, especially with a younger colony. Feed the ants seeds that they can carry. You'll notice them harvesting the seeds if they like them!
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Seeds like Kentucky Bluegrass, Dandelion, Sand Lovegrass, and many more in our Seed Mix are all great for this species!
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Hibernation
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Not necessary! They don't need to hibernate if you don't want them to, but are still able if it's your wish. If you keep them heated and fed, they'll simply keep growing. If, however, you wish to slow them down for hibernation (diapause), then simply slowly cool the colony until they're at 40°F. Leave them at this temperature for at least 8 weeks. During this time, make sure the nest is still hydrated and that they have seeds available to crack still. Once the 8 weeks has ended, warm them up over a few days. Once you return them to regular temperatures, growth will resume soon. Don't hibernate the colony when they still have eggs or pupae!
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Extreme Growth
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If you want to grow your Pogonomyrmex occidentalis extremely fast, follow these directions:
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1. Keep the colony at more than 90-95°F in much of the nest. The coldest parts should be in the low 80s.
2. Feed the colony lots of seeds so they have a huge storage.
3. Supplement the constant seed supply with insect protein daily or almost daily. Feed to mimic the size of the larvae pile!
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Feed them as much protein as they'll take when you do, and then a bit more!
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If you're looking for a place to find Pogonomyrmex occidentalis colonies, click here!
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