Location: Biological Control of Pests Research2011 Annual Report
1a. Objectives (from AD-416)
Objective 1. Identify new fire ant toxins from the defensive chemicals of sympatric ant species and their biosynthesis pathways. Component 5, Problem 5A. Objective 2. Investigate new fire ant semiochemicals and attractants and feeding stimulants from fire ant natural diets. Component 5, Problem 5A. Objective 3. Develop formulations using new and existing toxicants and behavior modifying compounds for managment of fire ants. Component 5, Problem 5A. Objective 4. Develop novel mosquito larvicidal formulations emphasizing efficacy and duration using Bacillus thuringiensis subsp. iIsraelensis ad the model active ingredient. Component 1, Problem 1A, Component 2, Problem 2A; Component 3, Problem 3F.
1b. Approach (from AD-416)
Chemical control is a critical component in fire ant management. Bait using slow-acting toxicants and mound treatment using synthetic contact insecticides are commonly used in fire ant control. With the ever-increasing concern over environmental safety, ideal fire ant control products of both bait and mound treatment must be less-toxic, long-lasting, and high-selective. There is not a single product in current market, which meets all the criteria. This research will focus on the discovery of natural compounds with new modes of action for fire ant control. One promising source of such compounds is the defensive chemicals of sympatric ant species. Beside the natural toxins, fire ant behavior modifying compounds will also be investigated. They include attractant, feeding stimulants, and repellants. These compounds can be used to improve the efficacy of fire ant control products without increasing the dose of toxins. New toxins and behavior modifying compounds will be used to formulate fire ant control products which are safer, more effective and more selective. Bacillus thuringiensis (Bt) is an attractive alternative to chemical insecticides because it is not toxic to vertebrates and to nontargetinsects. One strain, Bt subsp. israelensis (Bti), has been used for 2 decades for mosquito control. This research aims at developing technologies to improve the effectiveness of biolarvicides, using Bacillus thuringiensis subsp. Israelensis as the model active ingredient, through the development or improvement of novel delivery systems. In addition to utility of ecologically sound formulation constituents, a practical and economically feasible development process will be developed and implemented to enable technology transfer of any newly developed technologies.
3. Progress Report
Progress has been made in the following three areas: (1) Identification of new fire ant toxins from the defensive chemicals of sympatric ant species, toxicity of defensive chemicals in the Rasberry crazy ants, Nylanderia sp. nr. pubens, and the Carribean crazy ants, Nylanderia pubens, was compared to fire ants. (2) New fire ant semiochemicals were investigated, the surface chemicals on cricket eggs were identified. Those chemicals cause fire ants to discard cricket eggs instead of consuming them. This unique chemical profile may potentially be exploited in our effort to develop products which can protect biological materials in the field from being consumed by ants. (3) Formulation development using new and existing toxicants and behavior modifying compounds for management of fire ants: a prototype mound treatment formulation using ant defensive chemicals was developed.
1. Ant-derived chemicals for fire ant control. Synthetic pesticides cause public concern about health and environmental problems. Safe alternatives are needed. One alternative is natural insect toxicants because they are more environmentally friendly. In addition to identifying ant defensive chemicals, researchers at Stoneville, MS, have developed a prototype mound treatment formulation using natural ant defensive chemicals. These results are important in our attempt to develop new fire ant control products. This research may lead to new products for fire ant control.
2. Surface chemicals on cricket eggs. Crickets eggs have a similar surface chemical profile as that of a dead ant. Those unique chemicals elicit the ants’ corpse-carrying behavior, which protect eggs from being eaten by ants. In addition to the understanding the interaction between ants and other insects, this unique chemical profile may potentially be useful in protecting biological materials from being consumed by ants.
Zhao, L., Chen, J., Becnel, J.J., Kline, D.L., Clark, G.G., Linthicum, K. 2011. Identification and transcription profiling of Trypsin in Aedes taeniorhynchus (Diptera: Culicidae): Developmental regulation, blood feeding, and Permethrin exposure. Journal of Medical Entomology. 48(3):546-553.