Members of the Red Imported Fire Ant Lab work on ecology of fire ants and other ants of ecological or economic importance. Students have examined the effects of fire ants on box-nesting and ground-nesting birds, ground-dwelling mammals, herpetofauna, insects and spiders. Our group also cooperates with Dr. Lane Foil’s and Dr. Seth Johnson’s labs to look at integrated pest management of fire ants using cultural controls, biological controls and environmentally-friendly chemical controls such as baits. We also responded to the ecological disaster in south Louisiana caused by flooding associated with hurricanes Katrina and Rita. We are monitoring ant populations in hurricane-affected areas including rate of reinvasion and species turnover.
We are also interested in ant diversity in Louisiana. Using specimens and data from former and current students and my own explorations, a comprehensive book of “The Ants of Louisiana” is being written. We previously published the book, “The Pest Ants of Louisiana: A guide to their identification, biology, and control.” As we develop new methods of managing pest ants, we provide information to the public.
Other ants are also interesting to members of my laboratory. We study the Texas leafcutting ant or town ant. In the past three summers, we have excavated nests to determine nest structure and how the activities of these ants affect the macro- and microstructure of the soil. We also look at how their activities affect key nutrient levels in the soil. Ground-penetrating radar is being investigated for use in our studies with these interesting ants. Students interested in leafcutting ant basic biology and ecology are encouraged to apply to work in my program.
A small population of Comanche harvester ants has recently been rediscovered in Louisiana. Previously, some thought this species may have been extirpated by fire ants or by the efforts to suppress fire ants. Because harvester ants were eliminated in some areas, we are mapping and monitoring this small population. It is interesting to note that the current harvester ant population appears confined to highly disturbed, sandy habitats including those cleared by timber harvesting operations and trails maintained for off-road vehicles. I am looking for a student to study the effects of soil type and disturbance on the survival of this species.
The Pest Ants of Louisiana: a guide to their identification, biology, and control contains information on fifteen species of ants that occur in our state. A dichotomous key and numerous photographs help readers determine which species of ant is present around their home and garden.
The red imported fire ant, Solenopsis invicta Buren, was introduced into the US from South America in the 1930’s. The species can now be found in disturbed habitats in both rural and urban environments throughout the Southeast. The red imported fire ant is a highly invasive, pest species that causes severe economic and ecological damage and is a serious health concern for people and pets.
Excavation of Texas leafcutting ant, Atta texana (Buckley), nests require a team of researchers to thoroughly investigate colony activity. Pictured here (starting at top left) are Shawn Dash (former MS student), Michael Seymour (research associate), Andy Cline (former PhD student), Caren Carney (former research associate), Dr. Linda Hooper-Bùi (head of RIFA lab), (bottom row) Jennifer Fleming (former student worker), Katie O’Brien (former MS student), and Kristin Prejean (former student worker). A team of graduate students from Dartmouth College (not pictured) graciously provided valuable assistance on this particular dig.
Because Texas leafcutting ant, Atta texana (Buckley), nests may extend to depths of 3 meters or more below ground, heavy machinery is required to rapidly access the nest’s underground chambers.
An alate Texas leafcutting ant, Atta texana (Buckley), such as the male pictured here, may have hitchhikers riding on his body as he leaves the nest for mating flights. These small symbiotic roaches, Attaphila fungicola Wheeler, are phoretic on male and female reproductive leafcutting ants. Except during these ant mating flights, this little roach is only found deep within the fungus gardens of leafcutting ant nests
The large major worker, or soldier, Texas leafcutting ant, Atta texana (Buckley), is a formidable nest defender. Covered in stout, sharp spines and equipped with scissor-like mandibles, leafcutting ants make quick work of exposed (and frequently unexposed!) flesh on the human researchers. When inside a newly exposed nest, literally thousands of ants may come out to “greet” the visiting scientist!
The Texas leafcutting ant, Atta texana (Buckley), which occurs only in Texas and Louisiana, is a fungus-growing ant. Rather than eat the foliage they gather, the ants use the leaves as substrate upon which a fungus grows. The fungus garden, shown here in situ (about 2.5 meters below the surface), serves as the food resource for the colony.
Long thought extirpated from LA, a small population of the Comanche harvester ant, Pogonomyrmex comanche Wheeler, was recently rediscovered in north LA. These large ants have psammophores, a beard-like growth in which the ants pack small soil particles from nest excavation or, perhaps, food particles, as has been shown in laboratory studies.
In addition to the recent rediscovery of several Comanche harvester ant, Pogonomyrmex comanche Wheeler, colonies in north LA, newly-mated queens were found digging new nests. Queen harvester ants are readily distinguished from workers by the larger size of queens and by the robust thorax that allows for wing musculature (wings are shed after mating).
In his M.S. study at LSU, Michael Seymour discovered that with concentrated effort, red imported fire ants, Solenopsis invicta Buren, create large holes in Northern Bobwhite, Colinus virginianus, eggshells allowing for entry and exit of several workers at a time. The arrow points to a third egg that is in the process of being breached; note the missing bits of eggshell but intact membrane of the egg.