Pheidole morrisii
(Morris' Big-Headed Ant) Care Sheet
My name is Anthony Prothero, founder at Stateside Ants. I've kept a few large colonies of Pheidole morrisii in my 10+ years of antkeeping, and it is my opinion that this species is the best Pheidole in the eastern United States! The workers and queen are both yellow or orange, and this species has major workers with larger heads, used to reinforce colony power (defense and food processing).
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Pheidole morrisii is present in much of the eastern United States, where it's largely considered the best local Pheidole species one can acquire. They're showy, active, can grow extremely fast, and have a rather generalist diet! Pheidole morrisii colonies can be found for sale here!
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Short Sheet
Queen size: 8-10mm.
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Worker size: ~3-3.5mm.
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Major size: 4-5mm
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Founding method: Fully-claustral.
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Egg-worker times: Around 28-35 days, when heated.
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Polygynous?: No, usually monogyne.
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Ideal temperature: Around 83°F for most of the nest.
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Humidity: 80-90%+ in part of the nest. Lower in a different section.
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Hibernation temperature: 45F, but hibernation is completely optional. If you continue to heat and feed them, they won't want to hibernate!
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Protein preference: Extremely generalist. Roaches, fruit flies, mealworms, fish flakes, chicken, other table scraps, etc, are all accepted.
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Carbohydrate preference: Liquid sugars completely. This species rarely accepts seeds and should not be offered them.
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About the Queen
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Typically, a Pheidole morrisii queen will come in at just under a centimeter in length and have an orangish yellow tone to their exoskeleton. Their color can range, with some populations appearing more yellow or orange than others. They're fully claustral and tend to grow their first batch of workers pretty quickly, wasting no time! You don't need to feed them before workers. Their queens are the biggest native Pheidole in eastern North America.
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This species is typically monogynous. This means that only one queen is found per colony, and that queens who are put together will fight sooner or later.
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About Growth
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Pheidole morrisii can grow extremely fast! Within a year, a healthy colony should have at least hundreds of workers. If you fed them fervently and kept them warm, it could be much, much more. Major workers tend to appear in the 2nd or 3rd generation, and are not used for seed-cracking, but rather for processing proteins and colony defense.
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The colonies rarely achieve more than 5000-10000 workers at their full size.
Temperature & Setup
This species prefers to be kept warm throughout most of the setup (80ish), with a portion of their setup at a warmer temperature than that (closer to 85-90ish) for incubating brood on the extreme end. Make sure that this species always has moisture in their nest and access to water (note that a water FEEDER is not sufficient, their nest needs to have evaporating water sources or air moisture). A test tube setup provides this when the colony is young, but I recommend keeping a test tube attached as the colony grows and expands into a larger setup too. It's a good failsafe and if the ants are piling in the tube instead of the nest, you'll know there's something wrong with it.
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Try to keep this colony in the test tube for as long as possible! They do best there, and when it gets difficult to feed them in the tube (which is often quickly), try to give them a snug outworld.
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Pheidole morrisii isn't always the best (especially when the colony is young) at navigating overdecorated or complicated outworlds. Keep the outworld super simple when the colony is smaller: plaster or textured floor, entrance level entrance (not an entrance that they need to climb up to get back into), and absolutely no chemicals at all.​
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Make sure the outworld for this species is kept clean, as mold and mites can be pretty rampant if the humidity is high and you leave too much trash in their outworld. Their diet calls for lots of cleaning!
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You can heat the colony with a heating cable or a heat mat! If you do, make sure you heat them responsibly. Only heat part of the colony. If they're in a test tube, only heat the front of the test tube and allow the ants to choose where they want to be. If the ants are trying to get as far as possible, move the heat further. If they are trying to get closer, move it a tiny bit closer. Allow the ants to choose where they want to be; don't force a temperature on them!
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This species does not like wide-open nests with poor hydration. They don't seem to enjoy 3D printed or plastic-floored nests. When choosing a nest for this species, make sure it has good hydration and is not so huge that they won't fill at least half of it upon moving in. One of the biggest mistakes someone can make is moving a colony into a nest that is too large and doesn't work for their species.
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Feeding
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Pheidole morrisii are generalist ants with one Pheidole-specific caveat: they do not eat seeds. Although in some cases you can force them to eat seeds occasionally, it's not what they want to do and is extremely uncommon for them, especially in the wild. These ants are scavengers. They live off of liquid sugars for carbohydrates, and dead insects for protein.
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In captivity, their diet should reflect that. Make sure they're fed sugars often (or that a freshly filled liquid feeder is present at all times) like sugarwater, honeywater, or Sunburst Ant Nectar. As for protein, which is what grows the colony, this species is very generalist. Roaches, fruit flies, mealworms, anything works. When the colony is younger, they definitely prefer to be able to carry protein, so fruit flies is a good idea.
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Make sure to remove any uneaten food in the outworld after 16-24 hours. If you leave food in there, it could cause mold and such to appear.
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If you want your colony to grow quickly, feed them as much protein as they will consume, and then a bit more.
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Hibernation
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Pheidole morrisii can almost always skip hibernation. Hibernation (diapause in insects) can happen in the wild for some of them, but in captivity, you can keep them completely warm and fed through the winter, and they will continue strongly! It doesn't seem to have any bad effects on the ants. It's recommended not to hibernate most of them, as some queens could be from southern locations which aren't used to it. If you do, then hibernate them at around 45F for no more than around 4-6 weeks. Make sure there's still moisture in their setup during this time.
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Extreme Growth
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If you want your colony to grow incredibly fast, you should be overfeeding them. Keep offering as much protein as they’ll take, and then add some more and remove extras later. Make sure they’re well supplied with carbohydrates to keep the workers fueled. Heavy protein feeding signals the queen that resources are abundant, triggering her to lay more eggs—starting a cycle of rapid growth and increased demand for food, which you should then be ready to fulfill.
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When you stick to a strict feeding schedule, colonies don't reach their full potential. Instead, feed this species as much protein as they’ll accept, then add a little extra each day. A mix of roaches and fruit flies for protein daily, as well as constant or near-constant sugars should get this species growing! Keep in mind that they won't grow quickly without heat, though! Keep them warm, well-fed and frequently fed, and this species can explode in numbers!
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If you're looking for a place to get a Pheidole morrisii colony, click here!
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