Texas Leafcutter Ant—Part 2

[snaps fingers] We're picking back up with behavior and communication.

Texas leafcutter ants primarily communicate in two ways, pheromones and vibrations.

Pheromones are chemicals produced by animals for others to detect.

Texas leafcutter ant workers will leave trails of pheromones using their poison glands to help other ants follow the foraging trails.

They also produce a different pheromone with glands around their mandibles that are used to send out an alarm to other ants.

Low concentrations attract other ants, presumably, "There's something bad, you should come over here," while high concentrations trigger other ants to flee, presumably, "There's something bad, you should get away." As for communications via vibrations, leafcutter ants use what's called A, stridulation, B, vibration, or C, telecation.

Chicka B. Chicka C.

Can I get a drum roll please, chat? Chicka aye-aye.

[drum roll] The answer is A, stridulation.

[wrong answer sound] Chicka darn.

Chicka I hate this.

Yes, leafcutter ants use stridulation, the act of making a sound by rubbing together one's body parts.

I couldn't find how this is done in Texas leafcutter ants specifically, so all of the info on stridulation is for leafcutter ants more broadly.

The stridulation is done by raising and lowering the gaster, the end part of the abdomen, such that a scraper on the abdomen rubs against a file located on a different part of the abdomen.

The vibrations are sent into the ground or whatever the ant's standing on through their head.

While this does make an audible sound, the real communication is through those signals sent through the ground.

Insects have vibration sensors in all six legs.

Stridulation is primarily used as a stress signal to call for other ants to help, such as if an ant is trapped in a cave-in and needs to be dug out.

Certain species of leafcutter ant have been shown to stridulate when cutting a good leaf to signal other ants to join in.

One species stridulates while excavating parts of the nest to signal to other ants to dig in the same place.

Stridulation also has benefits other than communication.

When cutting leaves, they use the same process to create high frequency vibrations in sync with their chewing, creating complex vibrations of their mandibles of up to 1,000 vibrations per second.

These vibrations actually stiffen the leaf, allowing the ant to make a smoother cut.

The activity level of Texas leafcutter ants depends on the temperature.

They avoid hot days, harvesting leaves primarily in the cool of night during the summer months.