Submitted to: Book Chapter
Publication Type: Book / chapter
Publication Acceptance Date: 6/22/2007
Publication Date: 1/1/2008
Citation: Stanley, D.W., Miller, J.S. 2008. Eicosanoid actions in insect immunology. In: Beckage, N., editor. Insect Immunology. Elsevier. p. 49-67. Interpretive Summary: Application of classical insecticides has introduced severe problems in agricultural sustainability. The concept of biological control of insects is a potentially powerful alternative to classical insecticides. Biological control is based on the idea that direct application of insect-specific pathogens and parasites can reduce pest insect populations and the economic damage due to pest insects. The problem, however, is the efficiency of these organisms in biological control programs is limited by insect immune defense reactions to challenge. One approach to improving the efficiency of biocontrol agents would be to somehow disable insect immune reactions to viral, bacterial, fungal and parasitic infections. With this goal, we are investigating insect immune reactions to infection. In this chapter we report on identification of biological signals that are responsible for stimulating insect defenses to viral infection. This new information will be directly useful to scientists who are working to improve the efficacy of biological control methods. The ensuing improved biological control methods will benefit a wide range of agricultural producers by supporting the long-term sustainability of agriculture.
Technical Abstract: In this chapter we review eicosanoid actions in insect immunity. Eicosanoids are oxygenated metabolites of arachidonic acid (AA) and two other C20 polyunsaturated polyunsaturated fatty acids. Groups of eicosanoids include prostaglandins, lipoxygenase products and epoxyeicosatrienoic acids. These compounds are most well-studied in the context of biomedicine, however, we now know eicosanoids act in insect immune defense reactions. These include the cellular mechanisms responsible for clearing bacterial infection from hemolymph circulation and in microaggation and nodulation reactions. Eicosanoids also act in plasmatocyte spreading and hemocyte migration toward a chemical source. Various eicosanoids act in insect defenses against bacteria, fungi, protozoan and parasitoid challenge. The most recent data indicate eicosanoids act in insect defenses again viral infection. With a view to a coming generation of insect scientists, we lift up insect-virus interactions and mechanisms of eicosanoid actions as two of the visible frontiers of insect immunology.