title: Helicoverpa armigera (Lepidoptera: Noctuidae) larvae that survive sublethal doses of nucleopolyhedrovirus exhibit high metabolic rates.
abstract: To determine the effect of sublethal doses of Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HearSNPV) on the metabolic rate of H. armigera, the respiration rates of third instar H. armigera larvae inoculated with sublethal doses of HearSNPV were evaluated. Respiration rates, measured as the rate of CO(2) production (VCO(2)), were recorded daily using closed-system respirometry. By 4 days post-inoculation (dpi), the metabolic rates of LD(25) or LD(75) survivors were significantly higher than that of uninoculated controls. When dose data were pooled, the VCO(2) values of larvae that survived inoculation (0.0288mlh(-1)), the uninoculated controls (0.0250mlh(-1)), and the larvae that did not survive inoculation (0.0199mlh(-1)) differed significantly from one another. At 4dpi, the VCO(2) of the uninoculated controls were significantly lower than the VCO(2) of inoculation survivors, but significantly higher than the VCO(2) of inoculation non-survivors. Inoculation survivors may have had high metabolic rates due to a combination of viral replication, organ damage, and an energy-intensive induced cellular immune response. The high 4dpi metabolic rate of inoculation survivors may reflect an effective immune response and may be seen as the metabolic signature of larvae that are in the process of surviving inoculation with HearSNPV.
authors.affiliation: School of Molecular and Cell Biology, University of the Witwatersrand, Johannesburg, Private Bag 3, Wits 2050, South Africa. Gustav.Bouwer@wits.ac.za
authors.forename: Gustav
authors.initials: G
authors.lastname: Bouwer
authors.forename: Luisa
authors.initials: L
authors.lastname: Nardini
authors.forename: Frances D
authors.initials: FD
authors.lastname: Duncan
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D007814:Larva / Q000502:physiology / Q000821:virology; D016014:Linear Models; D009036:Moths / Q000502:physiology* / Q000821:virology*; D017924:Nucleopolyhedroviruses
chemical_list: D002245:Carbon Dioxide