Red Imported Fire Ant
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II. a. Imported Fire Ant Introduction and Biology Teaching Module for Advanced Master Gardener Training
Where are imported fire ants from? Where are they found in the US?
Need new map
History of Imported Fire Ants
1918: estimated introductions occurred of black imported fire ant (Solenopsis richteri) First introduced in Mobile, Alabama Red imported fire ant (S. invicta) followed in the early 1930’s The two species have hybridized Imported fire ants currently infest 330 million acres in the U.S. No natural enemies native to U.S.
IFA are the most destructive and costly ants in the U.S. IFA thrive in disturbed habitats, natural or man-made disturbances IFA continue to expand in the U.S. and their final range has yet to be reached
Habitat – found in open, sunny areas Mounds – large, no activity on surface Ants – very aggressive when disturbed Stings – painful, leave white pustule, sting more than once
Bite and Sting
Sting and Poison Gland
Types of Adult Fire Ants Winged female
Winged male Workers
UC Statewide IPM Program
Polymorphism in Worker Ants major
Adult fire ant workers have different morphs (polymorphic), i.e. major, media and minor, which greatly vary in body size. Majors are often used in identification because of their large size. Not all ant species exhibit polymorphism.
Fire Ant Anatomy – Major Body Parts AL= AN= CE= G= H= M= MT= P= PP= PR= PT= S= T=
alitrunk antenna H compound eye gaster head mandible AN mesothorax petiole post-petiole propodeum prothorax sting teeth (mandibular)
PR PT MT
CE M T
Solenopsis invicta Buren
Imported Fire Ant Anatomy USDA
Reddish to brown in color Large eyes Workers are polymorphic (1/6 – 1/5 in. long) Waist with 2 nodes No spine on propodeum 10 antennal segments 2-segmented antennal club Brown gaster with stinger Extremely aggressive
Photos by AntWeb
Comparing RIFA to a Carpenter Ant Red Imported Fire Ant
April Noble, Antweb.org
Common Black Carpenter Ant
Alex Wild 2003
Relative Size of Ant Workers of Various Species
Texas Imported Fire Ant Research & Management Plan
Mating and Dispersal
Mating flights occur on sunny days within 24 hours of rain, when temperatures are above 75ºF. Flights usually occur in spring and fall, but may occur after any rainfall.
Mating and Dispersal
Mating takes place 300 to 800 feet above the ground. After mating, females seek moist or reflective surfaces on which to land; male dies. Female is vulnerable to predators during and just after mating flight, especially to other fire ants.
New colonies are founded by newly mated females (queens) Once a queen lands, she removes her wings, burrows into the soil, and begins to lay eggs.
The first batch of eggs grow up to be worker ants Takes 20 – 45 days for adult maturity Worker ants are all sterile females capable of stinging Workers begin foraging and constructing the mound
A Queen’s Life EGG
After the first batch of workers is grown, the queen will always be tended by her workers. The queen can live 5-7 years and can lay eggs equal to her own body weight each day.
Mounds often not visible the first few months
Within six months a small mound becomes visible May have 100,000 ants present
Mature mounds may be quite large - Distinctive trait Mature colonies may contain 200,000 to 400,000 worker ants - Polymorphic colony population
Mound Structure Lateral foraging tunnel Exit / Entrance
Lateral foraging tunnel
Deep tunnels to water source
If the mound is disturbed…
Workers rush to save the queen and the immature ants
Workers move the young fire ants and the queen around the nest
Often move more than once per day Maintains near constant temperature and humidity
Fire Ant Life Stages
Complete metamorphosis 4 life stages Adult
Eggs found in brood chamber of a mound Eggs usually take 7-10 days to hatch
Larvae molt four times over 12-15 day period First three instars fed regurgitated liquid food
Black arrows point to a piece of solid food in the food basket below the mouth
Fourth instars are the only stage that can feed on solid food
Fire Ant Diet Fire ants eat a variety of foods
Pollet, LSU AgCenter
and are excellent foragers
What do fire ants eat?
Mostly other insects (predators) Tend aphids and scale insects for honeydew Plants and seeds that produce oils Fire ant workers DO NOT eat solid food Feed by trophallaxis
Foraging ants bring food back to the nest. Ants pass the food one to the other by regurgitating it from their crops. Adults pass liquid food around. Adults cannot digest solid food. Food is distributed to all members of the colony, including the queen.
Fire Ant Development
Worker immature and mature stages
Large workers live about 90-180+ days as adults Medium workers live about 60-90 days as adults Small workers live about 30-60 days as adults Regardless of size, they change jobs as they age - nurse - guard/excavator - forager
Development of Castes Worker immature and mature stages
Reproductive immature and mature stages
Pattern of development similar for worker and reproductive stages Males develop from unfertilized eggs Female reproductives get special food and hormones
Two Types of Colonies
Single queen (monogyne) - territorial and aggressive - limited life span of the colony Multiple queens (polygyne) - not territorial or aggressive toward each other - will adopt new queens - long-lived colonies
Monogyne Queen Colony
15-80 mounds per acre
Up to 7 million ants/acre
One queen per colony
Worker ants are territorial
Found in all southeastern states in the U.S.
Polygyne Queen Colony 200-800 mounds per acre Up to 14 million ants per acre More than one queen in each colony Colonies reproduce by budding
Worker ants are not territorial Predominant form in Texas
For More Information: http://www.extension.org/fire+ants
Publications, slide sets, streaming video, posters, and more…
Acknowledgments Thanks to the Texas Imported Fire Ant Research & Management Plan, Texas A&M University System, for the use of many of the images seen in this presentation. Portions of this presentation were made possible by a grant from the Southern Region Sustainable Agriculture Research and Education Professional Development Program. Authors: - Kerry Smith – Alabama Cooperative Extension System - Molly Keck – Texas AgriLife Extension Service - Bart Drees – Texas AgriLife Extension Service - David Williams – University of Florida - Ken and Rufina Ward, Alabama A&M University
Acknowledgments Reviewers: - Dale Pollet – Louisiana State University AgCenter - Karen Vail, University of Tennessee - Chazz Hesselein, Alabama Cooperative Extension System - Kathy Flanders, Alabama Cooperative Extension System Editor, Technical Facilitator: - Neal Lee