There has been an interest in the role saliva has on the pathogenesis of insect pathogens. However, no surgical techniques have been developed that inhibit the secretion of insect saliva in situ. Two techniques are described that inhibit the secretion of labial saliva from the caterpillar Helicoverpa zea. These are cauterizing the caterpillar’s spinneret or surgically removing the labial salivary gland. Caterpillars with inhibited or intact salivary secretions were allowed to feed on a 1:1 mixture of sucrose:glucose on glass fiber disks. After feeding, these disks were treated with peroxidase and diaminobenzidine, which results in a brown stain in the presence of the salivary protein glucose oxidase (GOX). The chemical assay determined that feeding by surgically ablated caterpillars did not stain the disks. This indicated that secretions of labial saliva was successfully inhibited. Caterpillars with inhibited saliva production appeared to feed at similar rates as the untreated caterpillars, pupate and enclose into adults. Glucose oxidase, a major labial salivary enzyme of H. zea, has been suggested to increase caterpillar survival through the suppression of insect pathogens.
These two methods of salivary inhibition are useful techniques for the clarification of the role that saliva plays in suppression of pathogenesis of insect pathogens.
Species 1: Lepidoptera Noctuidae Helicoverpa zea (corn earworm)
Species 2: Bacillales Bacillaceae Bacillus thuringiensis (Bt)
Keywords: glucose oxidase, pathogen
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