Pogonomyrmex barbatus Care Guide: Keeping the Red Harvester Ant

Pogonomyrmex barbatus, the red harvester ant, is one of the most iconic ant species kept in the hobby. Native to the deserts and grasslands of the southwestern United States and northern Mexico, these bold, reddish-brown ants are famous for their seed-based diet, their impressive trail networks, and their famously potent sting. Keeping them successfully comes down to one critical principle: keep it dry.

Live in the United States? Pogonomyrmex barbatus is a native American species, and our US store has a red harvester ant care guide written for US keepers, with equipment that ships from within the US.

Species Overview

Pogonomyrmex barbatus is found in Texas, New Mexico, Arizona, Oklahoma and into northern Mexico. In the wild, colonies nest in open, sunny ground, usually under a low mound that the workers keep clear of plants. A mature colony in the wild has around ten thousand workers. They are active during the day and easy to spot, sending out long foraging columns to harvest seeds from the surrounding area. As seed dispersers and soil engineers, they play an important role in desert and grassland ecosystems.

Queen and Worker Characteristics

Queens are around 15 to 17 mm and an even, warm reddish brown. Workers are around 6 to 10 mm with the same color. Worker size varies a little, but there is no separate soldier caste like in Camponotus or Pheidole. Workers have a robust, compact build and a psammophore: a basket of long hairs under the head that they use to carry sand and soil when digging.

Nuptial Flights

Pogonomyrmex barbatus is known for its large, synchronised mating flights after the summer rains. Large numbers of queens and males fly at the same time, which gives them the best chance of mating. If you buy a queen from another keeper, make sure she has mated and is already founding.

Founding Phase

Queens are fully claustral. Place a newly mated queen in a test tube setup and leave her completely undisturbed. How fast the first workers arrive depends mostly on warmth. Do not feed the queen during the founding phase: she does not need it, and opening the setup too often stresses her. The first workers are smaller than later ones, which is completely normal for harvester ants.

Temperature

This is a desert species and it needs warmth. Room temperature in northern Europe is usually too cool for good growth. Heat part of the nest or outworld with a heat mat or heat lamp, so the colony can choose a warm spot, roughly in the range of 25 to 30°C. Keep in mind that the setting of a heat mat is not the temperature inside the nest, so watch where the workers put their brood. A cooler colony will not die, but its brood will develop much more slowly.

Humidity: The Critical Factor

If there is one rule for Pogonomyrmex barbatus, it is this: keep the nest dry. This species comes from arid habitats and copes badly with too much moisture. Mold in the nest can kill a colony quickly. A small water source in the outworld, such as a test tube with a cotton plug or a damp cotton swab, kept well away from the nest entrance, is enough. Never moisten the nest itself.

Seeds must always stay dry as well. Wet seeds mold quickly, and the workers cannot remove them fast enough to stop it spreading. If you see workers carrying seeds out of the nest, those seeds have almost always become wet. Keep the outworld dry and offer seeds in small amounts that the colony uses up quickly.

Diet: Seeds and More

Seeds are the staple food. Offer a varied mix of small, hard seeds such as grass seed, millet, small sunflower seeds, sesame and hemp seed. Variety matters because each kind of seed offers different nutrients. Avoid seeds treated with pesticides or fungicides. Bird seed mixes from the pet store can work, but check the ingredients carefully.

Next to seeds, offer some protein now and then, such as fruit flies, mealworms or other small insects, and occasionally a small piece of fruit. Remove leftover protein quickly. Read more about ant nutrition in what do ants eat.

Housing

Give these ants an outworld with a generous layer of dry sand, so they can dig and forage naturally. Choose a nest that stays dry, such as a sand or red clay setup, or an acrylic nest with sand. Nests that hold a lot of moisture are less suitable for this species. Make the outworld spacious, because harvester ants are active foragers that like room.

Safety: The Sting

Pogonomyrmex barbatus workers have a powerful sting. Harvester ant venom is protein based and among the most potent insect venoms known. A sting can cause intense, lasting pain and, in rare cases, a serious allergic reaction. Workers defend their nest fiercely and sting readily when disturbed. Always work carefully, keep your hands away from the nest entrance and use tools rather than fingers. This species is not suitable for keepers with a known insect venom allergy.

Hibernation

Pogonomyrmex barbatus needs a winter rest. In the wild, colonies slow down a lot in winter. In captivity, give the colony a cooler period of a few months, for example in an unheated room. Reduce feeding gradually before winter and keep everything dry. In spring, let the temperature rise slowly and the colony will pick up again by itself.

Colony Growth and Size

Pogonomyrmex barbatus grows slowly in captivity. The colony stays small at first and only speeds up once there is a solid group of workers. How fast exactly differs per colony and depends a lot on warmth and food. A mature colony at home can grow to hundreds or even a few thousand workers, although colonies in the wild get much bigger.

Is This Species Right for You?

Pogonomyrmex barbatus is an intermediate to advanced species because of its need for warmth, a dry nest and a seed-based diet, and because of its defensive sting. Keepers with some experience who understand how important a dry setup is will find it manageable, but it is not recommended as a first species. Looking for an easier harvester ant to start with? Have a look at Messor barbarus. Ready for the challenge? Have a look at our Pogonomyrmex barbatus page.

Sources

• Gordon, D.M., 1999. Ants at Work: How an Insect Society Is Organized. Free Press.

• Taber, S.W., 1998. The World of the Harvester Ants. Texas A&M University Press.

• AntWiki. Pogonomyrmex barbatus.