Progress 11/01/99 to 05/31/05

Outputs
Red imported fire ant larvae were examined to investigate symbiotic bacteria that could be involved in nutrient distributions. The composition of the bacterial community in the fire ant larvae was described with culture-independent methods utilizing 16S rDNA sequencing. Sequenced bacteria clones from guts were predominantly from phylum Proteobacteria and family Enterobacteriacae. Of the 88 sequenced clones, 68% matched uncultured bacteria from environmental deposits, vertebrate and invertebrate guts. In contrast to bacteria found in the guts, 85% of the 88 clones sequenced from the whole larvae were of the phylum Firmicutes. The study suggests that the number of bacterial strains in larval guts may be far fewer than those present outside the guts since whole-larva samples did not yield many Proteobacteria. When using PCR amplifications, templates present in higher abundance may obscure those of lower abundance. Additional research addresses three questions: (1) which liquid feeding method does S. invicta dominantly employ, (2) does liquid viscosity and/or sugar concentration separately affect final crop load and intake rate of S. invicta, and (3) is this effect different when boric acid is added to the solution? Although no significant differences were found between total crop load (F(5,24) = 0.79, P = 0.5692), preliminary experiments performed on control (no Tylose) and constant viscosity solutions [10, 30, and 50% (w/w) sucrose solutions in which viscosity was normalized using Tylose to mirror a 50% sucrose solution] resulted in differences between intake rates (F(5,24) = 6.4, P = 0.0007). When ants were presented with a 10% sucrose control solution, the mean intake rate was 0.769 + 0.092 ul/s (Mean + SEM), whereas ants feeding on 10% sucrose/constant viscosity solution had a significantly lower intake rate (0.304 + 0.069 ul/s, Mean + SEM). Similar results were found when 30% sucrose solutions from both series were compared. The intake rate decreases as the sugar concentration increases to 50% sucrose (0.496 + 0.098 ul/s, Mean + SEM) in the control series; however, in the constant viscosity series, the trend is not as obvious. Observations of liquid feeding behavior suggest S. invicta will extent its mouthparts into a large droplet of solution and hold them relatively still while drinking; however, when the solution is presented as a thin film, the feeding behavior changes as the ant dips its glossa in and out of the solution. The Pest Ants of Louisiana: a Guide to Their Identification, Biology, and Control was written for all interested in the Formicidae of Louisiana. Fifteen common pest ants known to occur in Louisiana are included in this reference. A taxonomic key to genus and species is included, and each genus or species has its own account. Species accounts include identifying characteristics, a quick diagnosis for identification, separation from similar species, notes on biology and behavior, methods of control or management, and a color photograph of the species.

Impacts
Our projects are important to stakeholders, citizens, and scientists who are interested in biodiversity and preservation of natural resources. The new book makes it easy for readers to identify common pest ants. This book has been purchased by many people in Louisiana including pest management professionals, scientists, and teachers, and outside Louisiana this book has been distributed to Germany, Austria, Japan, Taiwan, Malaysia, and in California, Texas, South Carolina, Alabama, Florida, Mississippi, and Georgia within the US. Our knowledge of impact of fire ants on ant and invertebrate diversity is important to ecosystem managers. Particularly important is our landscape-level approach to fire ant impact on mammal populations. Land managers and foresters will use this information to make important habitat and forest management decisions, and they can have pre-emptive information to reduce secondary pest outbreaks as a result of control measures. Pest management professionals, scientists, and citizens that are involved in chemical or biological control of fire ants and other invasive ants will find our research interesting. Our research has helped pest management professionals identify and manage invasive ants. The knowledge of ecological factors affecting ant presence can be used by citizens and land managers to make landscape decisions to minimize fire ant presence in areas that have heavy human traffic. Our basic work on feeding dynamics and symbionts will be helpful in the future for further development of control measures for ants in areas where they are a pest.

Publications

• B. Lafleur, L.M. Hooper-Bui, E.P. Mumma, and J.P. Gaeghan. 2005. Soil fertility and plant growth in soils from pine forests and pine plantations: possible effect of red imported fire ants Solenopsis invicta (Buren). Pediobiologia. 49: 415-423.
• K.S. O Brien and L.M. Hooper-Bui. 2005. Hunger in Solenopsis invicta and their behavioral response to two liquid bait products. Journal of Economic Entomology. 98: 2153-2159.

Progress 01/01/04 to 12/31/04

Outputs
This study illustrates the effect of red imported fire ant, Solenopsis invicta Buren, activities on soil properties and the possible effects of these modifications on plant growth. In our greenhouse study, ant activity decreased soil pH, and increased phosphorus (P+) and potassium (K+) in the soil. After physical and chemical properties were obtained from the soil samples, Gardenia japonicus seedlings were planted to determine growth rate. In comparison to adjacent soil, ant nest soils from both habitats were lower in moisture content and bulk density and higher in NH4+. Ant nest soils were also higher in Ca2+, Mg2+, K+ and Na+ than in adjacent soils in longleaf-pine forests. Gardenia japonicus seedlings grown in nest soil from pine forests were an average of three times taller than those grown in adjacent soil, and those from pine plantations were twice as tall as those grown in adjacent soils. These results suggest that fire ants alter the physical and chemical properties of the soil. These soil modifications may favor plant growth since NH4+, a nutrient that limits growth, has been increased. We also examined the effect of the invasive fire ants on another invasive ants species, Argentine ants, in their shared expansion habitat. Fire ants foraging in Vienna sausage and honey vials were impacted by cloud cover, vegetation type, relative humidity (RH), and distance to nearest water. Fire ant mound presence was most affected by % clay in soil. Argentine ant presence was affected by temperature, RH, and soil bulk density. Laboratory studies were conducted to determine aggression demonstrated by fire ants and Argentine ants during interactions. When Argentine ants and fire ants interact, Argentine ants face a higher mortality risk, even though Argentine ants were often the initiators. Lab-reared fire ants were less aggressive toward each other than toward field-collected fire ants or Argentine ants. These bioassays may determine what occurs at the interface of two competing species. Previously Argentine ants were the major ant pests in Louisiana, and presently fire ants are the major ant pests in the area. No environmental factors were discovered which would explain this shift, however the aggression bioassays offer an explanation for this shift. When equal numbers of fire ants and Argentine ants interact, Argentine ants face a higher risk of mortality. The loss of intraspecific aggression and the ability Argentine ants have to build supercolonies does not appear to be enough of a competitive advantage to displace large fire ant populations. We report the first-ever comprehensive assessment of the Louisiana formicidae fauna. One hundred twenty-seven species from 38 genera and eight subfamilies are covered. This faunistic treatment gives valuable data on biodiversity and habitat selection of varied ant species, including keys to all subfamilies, genera, and species with illustrations, photographs, as well as a regional map for each species. Interesting results include the ten most common and abundant species throughout, exotic and pestiferous species, missing species, species lost, and previously unreported species.

Impacts
Our projects are important to stakeholders, citizens, and scientists who are interested in biodiversity and preservation of natural resources. Our knowledge of impact of fire ants on ant and invertebrate diversity is important to ecosystem managers. Particularly important is our landscape-level approach to fire ant impact on mammal populations. Land managers and foresters will use this information to make important habitat and forest management decisions. The information on interaction between fire ant and other species of ants will help scientists determine the whole impact of new biological control efforts, and they can have pre-emptive information to reduce secondary pest outbreaks as a result of control measures. Pest management professionals, scientists, and citizens that are involved in chemical or biological control of fire ants and other invasive ants will find our research interesting. Our research has helped pest management professionals identify and manage unknown invasive ants. The knowledge of ecological factors affecting ant presence can be used by citizens and land managers to make landscape decisions to minimize fire ant presence in areas that have heavy human traffic. The ant diversity study has been parlayed into "Ant Academy," a very popular course for ant identification attended by state workers, mosquito and termite abatement professionals, University professors and other workers, and pest management professionals.

Publications

• L.M. Hooper-Bui, M.K. Rust, and D.A. Reierson. 2004. Predation of the Endangered California Least Tern, Sterna antillarum browni (Mearns) by the southern fire ant, Solenopsis xyloni (McCook). Sociobiology. 43 (3): 401-418.
• K. O Brien and L.M. Hooper-Bui. 2004. Hunger in Solenopsis invicta and their behavioral response to two boric acid liquid baits. Proceedings of the National Conference on Urban Entomology. Phoenix, Az. May 2004.
• L.M. Hooper-Bui. 2004. Service Learning in Entomology. Proceedings of the National Conference on Urban Entomology. Phoenix, Az. May 2004.
• L.M. Hooper-Bui. 2004. Precision Treatments for Successful Management of Ants: Integrating What We Know about Baits, Barriers, and Behavior. Proceedings of the University of California 13th Annual Urban Pest Management Conference. March 2004.
• K. Landry, L.M. Hooper-Bui, and M. Chamberlain. 2004. Assessment of Landscape-level Impacts of Red Imported Fire Ants on Native Invertebrate Communities in Pine Dominated Forests. Proceedings of the National Red Imported Fire Ant Conference, Baton Rouge, La. March 2004.
• L.M. Hooper-Bui, M. Chamberlain, and J. Constible. 2004. Effect of Fire Ant Presence in Mammal Traps on Bait Theft and Trap Success in Two Ecosystems in Louisiana. Proceedings of the National Red Imported Fire Ant Conference, Baton Rouge, La. March 2004.

Progress 01/01/03 to 12/31/03

Outputs
Four projects are described here. The first investigated the diversity of ants of Louisiana through systematically documenting all the species of ants that live in Louisiana. In 1960, a report listed 128 species of ants that might occur in Louisiana but only 40 of them were collected in the state. We have collected and identified 52 species and have 20 morphospecies that are not yet identified. However, these do not include complex groups such as Pheidole, Camponotus, Solenopsis (Diplorhopturum), Formica, and small Pyramica and other cryptic ant species. The second is a project in which we examined the impact of fire ants on ground-dwelling mammals and invertebrates in two ecosystems at Alexander State Forest (pine mixed hardwood) and Sandy Hollow Wildlife Management Area(longleaf pine). Six 5-acre plots were established in each ecosystem and half of the plots were treated with Amdro to suppress fire ants. We trapped mammals biannually and invertebrates semimonthly. The Amdro suppressed the fire ants on treated plots, and we saw significant increases in spiders, mites & ticks, and leafhoppers in treated plots at Alexander State Forest. Also, Hispid Cotton Rat, Cotton Mouse, and White-footed Mouse were more numerous after treatment. At Sandy Hollow, spiders and grasshoppers increased when fire ants were suppressed, and Cotton Mouse numbers increased on plots that were treated. Two projects addressed different ecological factors that effect fire ant mounds density and presence in urban and natural ecosystems. One of the projects addresses ecological questions that will help determine whether mound counts or food traps are the best methods for determining fire ant population density, especially for areas with low population numbers such as areas where chemical and biological control have been implemented. We determined that in areas where researchers find low numbers of mounds, food traps are a more accurate estimation of the impact of fire ants in an ecosystem and where mound counts are higher, both mound counts and food traps are equally accurate. The second project identified factors such as soil type, canopy cover, and vegetation type as significant factors for fire ant presence. Ants were more commonly found in silt or loam/silt loam type soils and in areas where there were trees that provide some shade.

Impacts
Our projects are important to stakeholders, citizens, and scientists who are interested in biodiversity and preservation of natural resources. Our knowledge of impact of fire ants on ant and invertebrate diversity is important to ecosystem managers. Particularly important is our landscape-level approach to fire ant impact on mammal populations. Land managers and foresters will use this information to make important habitat and forest management decisions. The information on interaction between fire ant and other species of ants will help scientists determine the whole impact of new biological control efforts, and they can have pre-emptive information to reduce secondary pest outbreaks as a result of control measures. Pest management professionals, scientists, and citizens that are involved in chemical or biological control of fire ants and other invasive ants will find our research interesting. Our research has helped pest management professionals identify and manage unknown invasive ants. The knowledge of ecological factors affecting ant presence can be used by citizens and land managers to make landscape decisions to minimize fire ant presence in areas that have heavy human traffic.

Publications

• A.M. Pranschke, L.M. Hooper-Bui, and B. Moser. 2003. Efficacy of Bifenthrin Treatment Zones against Red Imported Fire Ant. Journal of Economic Entomology. 96:98-105.
• A.M. Pranschke and L.M. Hooper-Bui. 2003. Influence of Abiotic Factors on Red Imported Fire Ant Mound Population Ratings in Louisiana. Environmental Entomology. 32:204-207.
• M.A. Seymour and L.M. Hooper-Bui. 2003. Fire on the Mound: A Study of the Life and Times of Louisianas Red Imported Fire Ant. The Louisiana Conservationist. May/June 2003. 3 Pages with 6 color photos.

Progress 01/01/02 to 12/31/02

Outputs
We performed repellency and behavior bioassays to determine whether red imported fire ants (RIFA) detect and respond to bifenthrin treated substrates. Although RIFA do not initially detect bifenthrin and are not initially repelled, there appears to be a learned perceived mortality risk. This is indicated by avoidance of bifenthrin treated areas after 90 minutes of exposure to granular or liquid treatments at the label rate. We also used high performance liquid chromatography to measure the degradation rates of bifenthrin and deltamethrin in the environment. We used substrates commonly found on homeowners' property in the south such as pea gravel, soil, and pine straw. Deltamethrin and bifenthrin began breaking down on pea gravel after 48 hours of exposure to the environment. Another experiment at the Baton Rouge Metropolitan Airport demonstrated that a treatment of deltamethrin inside runway lights was the most effective way to control RIFA which readily colonize these warm, sheltered areas. We are studying the landscape-level effects of RIFA on wildlife such as small mammals, herpetofauna, and other insect species before and after treatment with Amdro. Louisiana is home to 8 ecoregions or unique habitat types. We are surveying these ecoregions for fire ants to determine their density and also to elucidate the number of other species, their relative abundance throughout the state, and their interactions with fire ants. This research will continue next year. We also investigated the chemistry and texture associated with soils in and adjacent to fire ant mounds in pine forests and pine plantations. Calcium, sodium, phosphorus, magnesium, and potassium were significantly higher in nest soils than in adjacent soils, and this resulted in significantly greater growth of plants tested. We also tested fire ant preference to different soil textures and found that fire ants prefer nest soil to nursery media with bark and sand.

Impacts
The repellency and behavior bioassays and the study on the degradation rates of bifenthrin and deltamethrin will improve our understanding of RIFA interactions with these chemicals and the environment explaining why the success of treatments is inconsistent. Because of RIFA presence in every ecoregion, they impact the welfare and survival of wildlife across the state. By identifying and establishing the importance of these biotic interactions and abiotic factors such as soil properties, the necessity and effectiveness of RIFA control can be determined.

Publications

• R. Boulay and L.M. Hooper-Bui. 2002. The effect of chlordimeform on the foraging activity of the red imported fire ant Solenopis invicta (Hymenoptera: Formicidae). Sociobiology 39:129-139.
• L.M. Hooper-Bui, A.G. Appel, and M.K. Rust. 2002. Preference of food particle size among several urban ant species. Econ. Entomol. 95:1222-1228.

Progress 01/01/01 to 12/31/01

Outputs
Results from our area-wide study in 1999 and 2000 have been released to the public and extension agents are promoting community-wide fire ant management in Louisiana. We investigated the size of insecticidal barriers to protect structures and bird nest boxes from RIFA attack. We demonstrated that bifenthrin barriers of 2-3m provide 8wks of complete ant protection and 20 wks of ant suppression. We also investigated the volume of water that results in the most efficacious application of liquid bifenthrin at a rate of 0.5oz per1000ft2. Larger volumes of water (5gal per1000ft2) resulted in poorer ant control than did smaller volume of water (1gal per 1000ft2) from a power sprayer. We conducted studies on protection of Japanese and Northern bobwhite quail from RIFA attack using Amdro on 5-acre plots. We found more than 60 percent mortality of domestic Japanese quail in untreated plots while native northern bobwhite quail, with very little mortality in treated and untreated plots, are less affected by fire ants. We also have begun studies to examine run-off of pesticides used for RIFA in nurseries and urban areas. These studies are currently being designed and implemented.

Impacts
Red imported fire ants infest every parish in Louisiana. Community programs such as LSU Agricultural Center's, Put the Fire Out, which emphasizes large-scale ant management have increased in popularity over the past year. Our work with the quail indicates that native northern bobwhites might be fire ant adapted and have better survival in RIFA infested areas than predicted.

Publications

• Hooper-Bui, L. M. 2001. Fire Ant Control in Urban Areas. Louisiana Agric. 44:2.
• Hooper-Bui, L. M. 2001. Fire Ant IPM in Louisiana. Southern Regional IPM Publication. USDA-CSREES IPM Program. KY cool. Ext. Serv. 48p.
• Boulay, R. and Hooper-Bui, L. M. 2002. The effect of chlordimeform on the foraging activity of red imported fire ants, Solenopsis invicta (Buren) (Hymenoptera: Formicidae) Sociobiology 39(1):129-139.
• Boulay, R. and Hooper-Bui, L. M. 2001. The role of the biogenic amine dopamine in egg production by isolated female red imported fire ants. Physiological Entomology 26:294-299.

Progress 01/01/00 to 12/31/00

Outputs
We explored large-scale and small-scale management of red imported fire ants. Large-scale applications (>1 acre) of both baits and contact insecticides provided >80% mound reduction, as did small-scale applications. Large-scale applications of bait suppress fire ants 3 times as long as small-scale applications and provided excellent control for six months. Contact insecticides broadcast over a large area are still providing excellent control eight months after application. Small-scale use of contact insecticides provides control for six months. Ant nutritional physiology has been studied in our laboratory. We have investigated the flow of sucrose, fructose, and glucose in both monogyne and polygyne forms of red imported fire ants. Monogyne ants fed their larvae more often than polygyne ants which may explain why monogyne individuals are typically larger than polygyne individuals. In additional physiological studies, dopamine was found to regulate egg production in fire ant queens. Both the protozoan, Thelohania solenopsae, and the ant decapitating fly, Psuedacteon tricuspis have been released in several areas of Louisiana. Both forms of biological control have survived over winter and have spread. The fly has infested new colonies up to a half a mile from the release site. The protozoan is spreading at a lesser rate but has been found outside of the original release site.

Impacts
Red imported fire ants infest every parish in Louisiana. Community programs such as LSU Agricultural Center's, Put the Fire Out, which emphasizes large-scale ant management have increased in popularity. This LSU AgCenter study demonstrated that large-scale treatment in urban areas may slow the re-invasion of red imported fire ants and reduce the number of treatments needed, cost of treatments and the amount of chemicals released in the urban environment. Treatment for fire ants with the large-scale broadcast approach, in which bait is bought in bulk, would have cost residents about $2 to $10, depending on the size of their yards. (For participating in the study, residents received the bait free.) This is compared to an estimated $20 to $100 each homeowner would have to pay per year to treat for red imported fire ants on his or her own. With large-scale fire ant treatments using broadcast granular baits, residents can expect to reduce ant control costs tenfold, reduce fire ant populations and experience more success.

Publications

• No publications reported this period