Biology and Control of Invasive Ants - AGRICULTURAL RESEARCH SERVICE

Goals / Objectives
1. Discover new bioactive compounds and approaches to improve control of fire ants and other invasive ants. 1A. Discover naturally occurring and environmentally benign synthetic compounds as toxins for invasive ant control. 1B. Discover naturally occurring and synthetic compounds as behaviormodification agents for invasive ant control. 2. Develop new management strategies using genetic-based technologies for fire ant and invasive ant control. 2A. Predict gene function and utilize existing genetic resources to test and develop invasive ant-specific assays, leading to control methods and products. 2B. Develop gene disruption assays and approaches for mitigating the impact of invasive ants. 2C. Identify and develop novel microbiome assays, and approaches for mitigating the impact of invasive ants. 3. Develop new and improved biorational pesticide delivery systems to control fire and other invasive ants.

Project Methods
Effective and environmentally benign ant toxins will be searched from various sources, including plants and other ants. In addition to ant toxins, we will search for behavior-modifying compounds that affect ant foraging and feeding using conventional bioassay-guided approaches and reverse chemical ecology approaches. These compounds can be very useful in improving ant developing control products. In the effort to develop gene disruption methods and materials, database comparisons will be conducted to identify target genes. Functional genomic techniques are essentially undeveloped in ants. We will begin by studying the genetics of key physiological processes within the colony. Because gene disruption experimentation is not standardized in ants, we will seek a visible phenotype, preferably non-lethal and visible in larvae, to provide an experimental positive control. We will initially focus on genetic disruption strategies which can disable the key physiological process of larval fitness and development. We will develop and utilize new molecular tools to validate, quantify, and develop genetic compounds and preparations that interfere with colony survival and resource exploitation. Additionally, preliminary studies identified unique viruses present in our regional populations of red imported fire ants. These discoveries need to be leveraged into ant-specific pathogens. The field of ant genomics and microbiome research has blossomed over the past 10 years. Individualized gene function studies, focusing on social form, chemosensory systems, neuropeptides, and oogenesis, have begun to shed light on the complex relationships between genes and phenotypes and behaviors. RNA interference studies have been performed on both fire ants and tawny crazy ants. A novel family of viruses was characterized. These investigations will lead innovation into new and improved control methods to mitigate invasive and destructive ants. Active ingredients or existing biorational pesticides will be used in developing new or improving existing biorational insecticide delivery systems. We will continue our effort in searching for adjuvants and synergists for improving the efficacy of mound treatment for fire ant control and spray treatment for tawny crazy ants. We will develop new water-resistant ant bait carriers using easily available local materials. Bait matrix will be developed and optimized for tawny crazy ants for both granular bait and liquid bait stations. Bait acceptance will be improved by using attractants and feeding stimulants. Bait selectivity will be enhanced by using selective repellants that attract targeted ants but repel non-targeted ants. We will continue our research on identifying effective synergists and surfactants for the final formulations.