Pheidole tepicana (Big Headed Harvester Ants) Invade the Border Fort in Cochise County, Arizona


The invasion caught us by surprise. I was sitting on the toilet, looked up, and saw the thousands of big headed harvester ants, Pheidole tepicana, lining the seams where the ceiling meets the walls in my bedroom.

The Border Fort was under attack.

Only later did I realize they were equally abundant along the ceiling seams in one end of the bathroom. I’d been taking care of paperwork on the john with hundreds of the little buggers clinging to the painted woodwork right over my head.

This would need to be dealt with immediately.

Thankfully, they invaded my corner of the house first. Only a few clusters had made it through the intervening wall and into Pam’s bathroom, with just a lone stray here and there having gone the other way, into the utility room. Had it been my wife’s quarters that had been invaded in force, the screaming might have deafened me all over again, even worse than the .357 Magnum I dinged my eardrums with in 2010.

Naturally, we didn’t know the exact species at first.

There was no doubt about it, though; we needed a pro. Time to call Zach, Pam’s son. Zach spent some months as a professional pest exterminator in western Texas a few years ago.

He went to school for it before he started, and he knows his stuff.

“They look like harvester ants,” I told him on the phone, “but there are definitely different sizes. I’m taking pictures and will have them blown up on the computer by the time you get here.”

Perusing the pics made it obvious there were three sizes of these ants, not just two. Alex Wild’s great photography (found him on Google) made the identification easy. The look was right, and Pheidole tepicana’s production of three worker cast sizes is unusual.

The three Pheidole tepicana worker castes are shown clearly in this grouping.

The three Pheidole tepicana worker castes are shown clearly in this grouping.

These clusters of Pheidole tepicana ants were strung all along the ceiling-to-walls seam on three sides of my bedroom as well as the west end of my bathroom.

These clusters of Pheidole tepicana ants were strung all along the ceiling-to-walls seam on three sides of my bedroom as well as the west end of my bathroom.

Super major (supersoldier) Pheidole tepicana, big headed harvester ant, Cochise County, Arizona.

Super major (supersoldier) Pheidole tepicana, big headed harvester ant, Cochise County, Arizona.

This one's a little blurry but does show the Pheidole tepicana supersoldier's awesome mandibles.

This one’s a little blurry but does show the Pheidole tepicana supersoldier’s awesome mandibles.

The thing is, we don’t have one thing against these big headed ants…except that we would really prefer not to sleep with them. So, lacking any other viable option we could think of, Zach hit the entire house, inside and outside, with his handy dandy bug killer spray. The outside was important; besides adding a barrier, there were the clusters we found under some of the eaves on the south side to consider.

That man is fast. I blinked a couple of times, and he was done. I was hanging out inside, tackling the computer to order a second type of insecticide which he’ll apply at a later date. Pam was in the car with the cats, keeping them calm except when Zach or I hove into view–at which point Gato cat would scream in outrage.

Gato doesn’t much like that car. The last time he was in it was the only time he ever had to go see the vet. Kitty’s got a long memory.

Zach explained that the stuff he used this time kills on contact. It dries clear in a matter of minutes, at which time it’s no longer particularly dangerous to humans or furry pets.

It remains dangerous to bugs for many weeks, though. The product dries with a layer of thousands of micro-crystals on its top surface. When Ms. Bug (like one of those female Pheidole tepicana big headed harvester ant girls) walks across said surface, the micro-crystals adhere to the body, penetrate the exoskeleton, break down in the process…and kill, just as before.

“For a while,” Zach informed us, “any bug you see will be a dead bug.”

After an hour or two, we left the cats in the house (the insecticide was thoroughly dry) and made a quick grocery run to the Safeway in Bisbee. When we got back, I decided it was time to see how clean the bug spray had gotten the ceiling-to-wall seam in my bedroom.

The photographic evidence was conclusive: Zach’s choice of insecticide definitely works.

I’ll sleep ant free tonight.

Aha!  The wall is ant free.  It could use a fresh coat of paint, but that's another story.

Aha! The wall is ant free. It could use a fresh coat of paint, but that’s another story.

Addendum: After publishing this post last night and later getting my eight hours of beauty rest, having “slept on it”, I got up knowing something else about our big headed Pheidole tepicana ant invasion.

We had caused the whole thing.

We’d known all year long that we had countless harvester ant colonies spotted around the area, at least half a dozen of them within 30 yards of the house. None of the oversized supersoldier individuals were noted, but foragers from every such colony gleaned an ongoing and bountiful harvest from our bird feeder gazebo.

Pam’s son and his wife had given my beloved a bird feeder for Mother’s Day. She was thrilled to get it, and even more thrilled when I built a bird feeder gazebo in which to hang the feeder. The gazebo sits right outside the front kitchen window, just a few feet from the glass for easy enjoyment of our feathered friends.

Now, fast forward to one of the scientific articles on Pheidole tepicana I found online while researching material for this post.

It stated, among other things, that the giant big head individuals, the super majors or supersoldiers, do not always manifest in a colony. In fact, it’s rather rare, except under one of two conditions:

    1. A scientist adds a specific juvenile hormone, methoprene, to the ant larva at exactly the right stage in its development. Methoprene acts as a growth regulator and is rather a double edged sword–it is used as an insecticide in some cases, but can also be used in any Pheidole species to produce big headed ants.

    2. The food supply for the colony (or colonies) is truly abundant for an extended period of time.

Well, we’re no scientists here at the Border Fort, but we surely did provide the local harvester ants with an astoundingly abundant food supply this year. The monsoon rains were heavier than usual, resulting in an amazing overgrowth of vegetation, so there were plenty of grass seeds to go around. Added to that, thousands of seeds from the bird feeder fell onto and over the side of the concrete pad every time the wind blew or a house finch flew in to have breakfast, lunch, or dinner.

Essentially, we might as well have been force feeding the harvester ants to produce super majors on purpose; the result was the same as if we had.

One colony kept trying to reestablish itself right under the concrete pad, just three feet from the front porch step. We hit those critters with a lot of Raid spray over the summer months, most likely never killing all the queens, just slowing things down completely.

But even without the gazebo colony, there were plenty of others…and at least one of those colonies, perhaps several of them, grew fat, big headed, and crazy.

Pheidole tepicana ants are not known for actually nesting inside houses. They usually nest outside, though they may well send foragers inside. But these weren’t just foragers. They included all three castes of workers, and Zach, prior to applying the insecticide spray, advised us (after inspecting closely with his flashlight) that the minor workers on the move were “all carrying eggs”.

This was a major migration, entirely out of route (not typical) for the species…and the Border Fort Granary Abundance caused it, sure as can be.

My wife is sleeping at the moment. Later today, when she’s up, I’ll have to tell her about this insight. She’ll get it; demyelinated brain and MS notwithstanding, her mind still makes connections like that in a hurry.

She just won’t like it.

We’ll need to stop feeding the birds, at least close in. The gazebo can never again be used for its original intended purpose.

At least one house finch pair won’t like it, either. When the 20 or so birds disappeared, no longer making lengthy flights to the feeder because they had eggs and/or baby birds at home to tend, our local resident finches kept coming. They have gotten unbelievably fat; it’s almost a wonder they can still fly…and now they’re going to be put on a Weight Watchers diet, just as winter is coming on.

Those two live here year around. They should be leaner and healthier come spring, eh?

As for us, we’re already lean enough, so we’ll have to settle to being a bit wiser for the experience.

The bird feeder gazebo in its early heyday, before the porch was finished and long before we were overfeeding the local harvester ants.

The bird feeder gazebo in its early heyday, before the porch was finished and long before we realized we were overfeeding the local harvester ants to the point of producing big headed supersoldiers and invading the Border Fort.

Update: October 28, 2013. Not wanting to give up the gazebo, we decided to put the bird feeder to use as a decorative object. I went to Hobby Lobby today and purchased 20 pounds worth of colored glass gems and marbles, poured most of them into the feeder (after cleaning it a bit), and hung the feeder back up in the gazebo.

Here’s the result.

Black Widow and Tank 012




8 thoughts on “Pheidole tepicana (Big Headed Harvester Ants) Invade the Border Fort in Cochise County, Arizona

  1. I hate ants in the house. Those things bite and it itches and hurts for several days. Glad you got rid of them. I ended up with a little trail of sugar ants in my house this last summer and got a couple of ant baits to put in the kitchen, where they were. The ants disappeared in just a few days.

  2. We’re not fond of ants in the house, either. As for sugar ants, we had them bugging us for most of the year, off and on, especially around the utility room sink. Used up a lot of ant bait, too; they kept coming back every time we bait-killed a bunch of them. Haven’t seen any since the monsoons hit hard in July, though, and we’re thinking maybe they got drowned when the house was flooded or something.

    Today’s bunch included a lot bigger breed of ant, obviously. Those oversized supersoldier versions made a big -CRUNCH!- when smashed, which no tiny sugar ant would do.

  3. I think I would have freaked out if I looked up and saw those fat ants looming above my head. Thank goodness Zach was able to get rid of them.

    I feel bad for Pam. I know how much she wanted that bird gazebo. Maybe you can use it for a plant hanger. Do orchids grow in Arizona?

  4. Pam’s with you on the freakout trail. She states unequivocally that if the major infestation had been in her bedroom, she would NOT have gone to sleep in the house that night, but would have insisted on taking a blanket and pillow out to the Subaru.

    I don’t know about orchids, but it turns out she had figured out the bird feeder angle before I did…and we have a replacement solution. I have to get going, hit town on errands–one of which will be to visit Hobby Lobby to pick up a bunch of colored glass beads with which to fill the bird feeder. We’re both excited about that. I’ll have to take a picture when it’s done and post it here, eh?

  5. I’ll bet the new feeder looks awesome when the sun hits it. Very colorful. Too bad it has to be bye, bye birdie! Damn ants!

  6. Definitely. As it stands, the sun only hits it (since I placed in the most protected place I could) early in the a.m., when the sun first comes up. Which mean I won’t often notice it, but since Pam’s the early riser….:)

    I don’t really see it as being the fault of the aunts, though. The local house finch pair that kept eating seed as long as we kept the feeder up…well, they’d gotten way too fat for their own health. Heart attack, stroke, or too slow to evade a predator. This is easy feeding country for birds, plenty of wild grass seeds, and we were in fact doing them no favors with the additional feeder.

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