IDENTIFICATION AND CHARACTERIZATION OF PEST INSECT IMMUNE RESPONSES TO BIOLOGICAL CONTROL AGENTS
Location: Biological Control of Insects Research
Title: Eicosanoids influence insect susceptibility to nucleopolyhedroviruses
Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 9, 2009
Publication Date: November 1, 2009
Citation: Stanley, D.W., Shapiro, M. 2009. Eicosanoids influence insect susceptibility to nucleopolyhedroviruses. Journal of Invertebrate Pathology. 102(3):245-249.
Interpretive Summary: Baculoviruses are pathogenic viruses responsible for lethal infections in insects. Of all known viruses, these are the most beneficial to humans. They are major elements of sustained agriculture because they are used to manage populations of pest, but not beneficial, insects. Baculoviruses are used globally in some biological control programs. A serious problem, however, is their full potential as biopesticides has not been reached. This is because we do not understand why some pest insect species are resistant to baculoviruses. We have identified a biochemical signal operating within insects that mediate insect resistance to viruses. This finding will allow future research to manipulate the signal system, which will help understand how insects are able to resist baculoviruses. Longer term, this research will directly help growers and users of agricultural products by promoting sustainable agriculture.
Nine pharmaceutical inhibitors of eicosanoid biosynthesis (e.g., bromophenacyl bromide, clotrimazole, diclofenamic acid, esculetin, flufenamic acid, domethacin, nimesulide, sulindac, tolfenamic acid) that increased the susceptibility of the gypsy moth, Lymantria dispar (L.), to the nucleopolyhedrovirus LdMNPV were tested against the beet armyworm Spodoptera exigua (Hubner), the corn earworm Helicoverpa zea (Boddie) and the fall armyworm Spodoptera frugiperda (J.E. Smith) and their respective NPVs to determine whether these compounds also alter the susceptibility of these insects. The susceptibility of the beet armyworm was increased by six inhibitors (bromophenacyl bromide, clotrimazole, diclofenic acid, esculetin, flufenamic acid, nimesulide). The susceptibility of the fall armyworm was increased by seven inhibitors, (bromophenacyl bromide, diclofenamic acid, esculetin, indomethacin, nimesulide, sulindac, tolfenamic acid), whereas the susceptibility of the corn earworm was increased by only one inhibitor (sulindac). The influence of the cyclooxygenase inhibitor, indomethacin was expressed in a dose-related manner in beet armyworms. We infer from these findings that eicosanoids, including prostaglandins and lipoxygenase products, act in insect anti-viral defenses.