The giant, ant-like things were absolutely everywhere, either lying on the ground dead or busily digging holes in the newly moistened earth. Some of them had wings while others didn’t, and there were large ones as well as small ones. I took a good look at them, and couldn’t help wondering “what the heck are those things?” I’m willing to bet lots of other folks were thinking the same thing.
A little bit of research soon revealed the answer. Turns out the insects were indeed ants. Specifically, they were specimens of the ant universally hated by gardeners – Atta texana. Or in regular parlance, the notorious Texas leafcutter ant. These ants also go by several other names, including cut ant, parasol ant, night ant, fungus ant and town ant.
Following spring and early summer rains, giant-sized Atta texana queens measuring about 3/4 of an inch in length, launch themselves on maiden flights with the goal of establishing new colonies. Smaller males fly with them and, after mating, the males die. The queens subsequently lose their wings and, once back on the ground, each queen digs a burrow and starts a new colony.
Cut ant colonies are well known for producing large mounding beds that can span many feet across, with the openings of “feeder” tunnels being located as much as 500 feet away from the main colony.
Colonies can house up to two million ants with most of the ants being sterile female workers. Ants can measure anywhere from 1/16th to half an inch in length, depending upon their role in the colony. The largest workers often act as soldier ants, protecting the colony.
The soil that creates the impressively big beds comes from large chambers excavated by the workers, which can be located as much as 15 to 20 feet below the ground surface. The ants stock these chambers with foraged leaves and other vegetation, upon which a particular type of fungus is grown. It is this fungus, not the vegetation, which the ants and their larvae eat.
Interestingly enough, each new cut ant queen carries a small bit of this fungus in her mandibles during her mating flight so that she will have a “start” for her new colony. As far as anyone knows, this fungus is the ant’s only food source, which is why cut ant colonies are so hard for homeowners to get rid of - the ants don’t eat ant bait.
Cut ants are well known for their ability to strip vegetation overnight and, as such, they can be a real problem for homeowners. They can also bite and, given their strong mandibles, it should come as no surprise that these ants can deliver a good pinch if compelled to do so.
One thing homeowners should be aware of - foundations can be potentially damaged by cut ants if they situate their colony underneath a house. In their quest to dig their large underground chambers, these ants have been known to cause cracks in house slabs and cause unstable conditions for pier and beam houses.
To learn more about Texas leafcutter ants, go to http://www.blueboard.com/leafcutters/index.htm, and also to http://citybugs.tamu.edu/factsheets/landscape/ants/ent-1002/.