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SMALL BUT
FIERCE
Texas leaf cutting ants are an amazing force to be reckoned with
Sept. 3, 2022
By Victoria County Master Gardener Virginia Ruschhaupt
Watch for next week's Gardeners' Dirt with more information on treatment of Texas leaf cutting ants.
PHOTO CONTRIBUTED BY JOSEPH CONNORS IV/SOUTH TEXAS BORDER CHAPTER TEXAS MASTER NATURALIST
Texas leaf cutting ant
PHOTO CONTRIBUTED BY SHUTTERSTOCK
Texas leaf cutting ants at work
How do leaf cutting ants cut off leaves off of trees? SEE ON YOUTUBE
REFERENCES
Texas Leaf Cutting Ant, Atta texana - https://urbanentomology.tamu.edu/urban-pests/ants/leaf_cutting/
Master Gardener - Entomology Advanced Training - Dr. Pluckett, Urban Entomology
F@stSheet Ent-1029 Texas Leaf Cutting Ant - AgriLife Extension -
IN THIS FACT SHEET - DESCRIPTION, LIFE HISTORY AND HABITS, DAMAGE SYMPTOMS, CONTROL SAFETY FIRST
Leaf Cutter Ants - https://aggie-horticulture.tamu.edu/archives/parsons/misc/leafcut.html
Texas Leaf Cutting Ant - https://citybugs.tamu.edu/factsheets/landscape/ants/ent-1002/
Forest Health - Texas Leaf Cutting Ant - Texas A&M Forest Service - https://tfsweb.tamu.edu/LeafCuttingAnt/
Texas Leafcutting Ant - https://texasinsects.tamu.edu/texas-leafcutting-ant/
Homeowners Left Vulnerable to Leafcutter Ant Excavations - https://agrilifetoday.tamu.edu/2005/03/29/homeowners-left-vulnerable-to-leafcutter-ant-excavations/
Texas Leaf cutter pdf - http://counties.agrilife.org/williamson/files/2011/07/Texas_Leaf_Cutting_Ants_10.pdf
Biology and Management of Texas Leaf Cutter Ant - https://academic.oup.com/jipm/article/8/1/16/3869833
Complete Excavation and Mapping of a Texas Leafcutting Ant Nest - https://academic.oup.com/aesa/article/99/5/891/12176 -
Species Atta texana - Texas Leaf-cutting Ant - https://bugguide.net/node/view/50478
Atta texana, Texas Leaf Cutter Ant (Hymenoptera: Formicidae) - https://lsuagcenter.com/articles/page1649168993168
Leaf Cutter Ants – Surprising Facts and Adaptations; with Pictures and Videos Written by George Srankoin - https://biogeoplanet.com/leaf-cutter-ants-facts-and-adaptations/
Atta texana - https://animaldiversity.org/accounts/Atta_texana/
Leafcutter ants use prehensile legs to help chop up leaves Flexible leg tips allow ants to hold and cut leaves with precision - https://www.science.org/content/article/leafcutter-ants-use-prehensile-legs-help-chop-leaves
Nothing is worse than the dreaded fire ant, unless you have met the Texas leaf cutting ant in full force on your own property. It’s a force to be reckoned with.
Damage
Texas leaf cutting ants, officially Atta texana, aka town ant, parasol ant or cut ant, are seen in great numbers following trails while carrying leaf fragments high over their bodies. If they only took a few leaves, we could live with them; but that’s not their mode of operation. Their quick demolition of my beloved daylilies prompted diligent research and a fierce battle.
These ants harvest leaves from over 200 plant species and are a major pest of agricultural and ornamental plants. A small to medium sized tree can be defoliated in less than 24 hours.
Since ideal harvesting air temperature is between 45 and 80 degrees, they prefer the night shift during the summer. Texas weather allows them to work almost full-time in other seasons.
According to Texas A&M Forest Service, this ant kills pine seedlings on nearly 12,000 acres in an average year, at a cost of $2.3 million for control and seedling replacement. Pines are not even their favorite, usually only chosen in the bare winter.
Identification
Texans don’t need to think twice about insect identification when we see the active parade of leaf fragments. Texas leaf cutting ants are rust brown to dull dark brown. Workers are about 1/2 inch long, with soldiers, reproductives with wings and queens being much larger. Measurements are dependent on the ant’s caste or role in the colony and even the age of the colony.
Atta texana is differentiated from other ants by three pairs of prominent spines on their thorax, the middle division of the ant’s body, and one pair of spines on the back of the head and an 11-segmented antennae.
The colony
Sandy or loamy soil is preferred for the colony, which looks like a real village. According to Michael Merchant and Bastiaan Drees, entomologists with Texas A&M AgriLife Extension Service, a colony above ground consists of numerous crater-shaped mounds, each 5-inches to 14-inches high and up to 1 1/2 feet in diameter, with a central entrance hole. There may be hundreds of entrance or feeder holes throughout the colony. No other ant in Texas achieves the enormity of these mounds.
A colony can be 50 to 80 feet across and up to 20 feet deep, with complex interconnected vertical and lateral tunnels and chambers serving specialized purposes. Lateral foraging tunnels can extend 500 feet underground. External foraging trails may extend another 500 feet in various directions. The colony or nest can occupy up to 4,500 square feet.
The population of a colony can reach 2 million ants, with up to five fertile queens, each continually producing eggs.
Foraging and farming
Upon finding a preferred tree, shrub, or other plant, ant workers cut circular-shaped pieces from the leaves with their razor-sharp mandibles, usually dropping the leaves to the ground. Other workers pick up the pieces and carry the fragments along a foraging trail to a feeder hole. Pheromones assist in marking the trails.
Leaf fragments are further decimated at the feeder entrance site and taken further underground to the appropriate chamber to grow a specialized fungus. This fungus is the sole source of food eaten by Atta texana and their larvae.
Specialized ants perform many complicated tasks to process and pulverize the leaves, incorporate them into the fungal mixture, and keep it all free from contamination to achieve the fungal end product. Each species of leafcutter ant makes its own unique fungus. Like humans at work, the ants troubleshoot throughout the process and make corrections as needed.
Control
Usual methods of ant control are a challenge with cut ants due to complexity of the colony and their exclusive diet of fungus. Are there solutions? See the next issue of Gardeners’ Dirt.
The Gardeners’ Dirt is written by members of the Victoria County Master Gardener Association, an educational outreach of Texas A&M AgriLife Extension – Victoria County. Mail your questions in care of the Advocate, P.O. Box 1518, Victoria, TX 77901; or vcmga@vicad.com, or comment on this column at VictoriaAdvocate.com.
ph: 361-935-1556
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