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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGY, GENOMICS, AND INTEGRATED PEST MANAGEMENT OF INVASIVE ANTS

Location: Imported Fire Ant and Household Insects

Project Number: 6036-32000-044-00
Project Type: Appropriated

Start Date: Sep 08, 2009
End Date: Sep 07, 2014

Objective:
1. Develop functional genomic resources and employ these resources to examine the genetic basis of biological traits that can potentially be used for biologically based control, including implications for the geographic origins of infestations. The existing objective 1 will be enhanced as follows: 1.1 Utilize key biological resources, next generation sequencing technology, and state-of-the-art bioinformatics approaches to sequence and annotate the genomes, transcriptomes, proteomes and metagenomes of important and emerging insect pests of veterinary importance. 1.2 Develop and use molecular tools for population genomics studies of veterinary pests in their indigenous and invasive ranges to understand the role of different evolutionary forces in shaping phenotypic variation of high-consequence to agriculture. 1.3 Apply biogeographic, spatial, and temporal analyses to quantify and predict economically important or potential veterinary pest distributional changes, and integrate these analyses with genetic studies of rapid evolution and adaptation of pests to new or changing environments. 2. Expand current biocontrol efforts by discovering and developing new parasites and pathogens; improving mass culture and field release systems; and defining host specificity of natural enemies. 3. Characterize semiochemicals through investigation of pheromone biosynthesis and release; use these findings to develop novel biologically-based control and surveillance methods, including the detection and treatment of incipient or low level populations. Determine the genetic/chemical bases for differential fire ant sensitivity to corn and turfgrass germplasm and evaluate potential for novel control of fire ants. 4. Develop integrated pest management plans that utilize available control methods, perform comprehensive risk assessment, and that can be adapted to specific stakeholder needs, including local eradication.

Approach:
1. Normalized cDNA libraries will be sequenced using 454-pyrosequencing technology. Resulting sequences assembled and automatically and manually annotated for key words, gene function, and Gene Ontology terms. The 454 data will be used to search for potential microbes infecting fire ants and determine their nature, distribution, relationship, and effects of these microbes in fire ants. SNPs within the data will be identified and applied to high-resolution identification of the source population of introduced S. invicta. Microarrays will be constructed and used to identify differentially expressed genes from parasite-infected and -uninfected fire ants and identify genes co-expressed with the social form-specific gene Gp-9 allelic variants. 2. Microsporidia: After approval, V. invictae will be released in the U.S. following the procedures for K. solenopsae introductions. Phorid Flies: Additional decapitating phorid flies will be released using procedures based on our previous successful releases in the U.S. The impact of phorid flies will be assessed by multiple methods, e.g. monitoring the establishment, expansion, distribution and parasitism rates of phorid fly species across the fire ant range. Viruses: With purified preparations of SINV, a number of basic studies will be conducted, including lethal dose evaluations, colony transmission studies, field-testing, and formulation development. 3. The function of the PBAN/pyrokinin family of neuropeptides will be investigated by: a) in vivo injection into female and male sexuals and immatures and observed for phenotypic change; and b) use of RNAi gene knockout methods ¬ followed by monitoring for phenotypic and/or behavioral changes. Monitoring and surveillance methods will be developed for fire ants, using known attractants. Existing fire ant bioassays will be adapted and applied to non-fire ant invasive pest ant species to create better baits and effective monitoring systems, e.g. attractants and repellents. There are many genetically characterized inbred lines of maize, e.g. yellow and white that will be tested for ant preference/damage at seed germination and seedling stages, and root development differences will be examined (phenotypic traits). Differential gene expression profiles will be used to identify genes of interest. Turfgrasses will be re-examined to determine which species is most inhibitory to fire ant colony development. Long-term molecular studies will identify the genetic basis of observed differences. 4. Potential geographic range expansion of tramp ant species will be modeled using CLIMEX a program that can be used to predict where a pest ant of interest can survive. Phagostimulants will be studied to improve the acceptability of baits for non-Solenopsis pest ants by adapting methods used for fire ants. Standard laboratory colony tests will be used to assess bait formulation effects on brood volume, adult populations, and queen survivorship. A combination of monitoring tools, baits, and biologically based-control methods will be applied to selected invasive ant species as these new tools become available.

Last Modified: 11/28/2014
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