Insect of the Week - Army Ants

If you hear the term "army ant" you probably think of ants that live in the rainforest or tropical environments.  But I think you would be surprised to learn that army ants are all around - or should I say under - us.  They are subterranean ants that can have massive numbers and every so often decide to come above ground to make themselves known.

While these ants are usually rarely seen above ground, this week alone, I have identified army ants from two different locations!  I have to say, it was quite exciting for me to come into the office on a Monday morning and get to identify two samples of something I rarely ever see!  After polling a few of my entomologist colleagues, I found that the San Antonio area is not alone in seeing this phenomenon.  

Army ants.  Notice the lack of large eyes on the head.

Army ants are not considered a pest species because we so seldom actually encounter them.  But when we do, you usually see huge numbers - such great numbers that they are alarming.  Usually the numbers of army ants you see would indicate a heavy infestation, but not in the case of army ants.

They are predatory under the ground, feeding on other insects and invertebrates.  Most species have huge mandibles that are noticeable without a microscope or magnifier.  Their bodies are a reddish/orange in color and pretty uniform in that color.  The workers have various sizes, but they are all on the small size - similar to a sugar ant or small fire ant.  The coolest thing about their morphology is that they have no eyes!  Well, they may have eyes, but they are teeny dots on their head and nothing like other ant eyes.  We can assuming they lack well developed compound eyes because they have no need, living in the dark their entire lives.

Army ant workers and alates found on the bathroom floor, coming from
under the toilet. Photo credit - Jeff Schneider.

My best guess is that the reason we are seeing so many army ants is because it's dry and hot.  They are moving above ground to find food and other resources.  If you happen to find army ants above ground, savor the unique situation you are in!  Likely, they'll disappear as quickly as they arrived and you'll never see them again.