Midgut pH Profile and Energy Differences in Lipid, Protein and Glycogen Metabolism of Bacillus thuringiensis Cry1Ac Toxin and Cypovirus-infected Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae)

In this research, the effect and interaction of Cry1Ac and Helicoverpa armigera Cytoplasmic Polyhedrosis Virus, HaCPV (Chinese strain) on body weight, midgut pH, total lipid, glycogen and soluble protein contents of Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) larvae were studied. Cry1Ac is a toxic protein produced by Bacillus thuringiensis (Berliner). When larvae were separately exposed to HaCPV (3 x 10(7) PIB ml(-1)) or Cry1Ac (0.9 mu g g(-1)), body weight, glycogen, soluble protein, and total lipid content of them, compared with the control, were significantly reduced. The effects of their combination at the same concentrations on the above mentioned parameters were more pronounced, which indicated their synergistic or additive influence. The midgut pH in larvae was significantly declined from 10.5 (in control) to 7.5 when larvae fed on diets containing HaCPV or Cry1Ac, and it was reduced to 8 when they were fed with their combination.