CHARACTERIZATION OF THE MELANOPLUS-SANGUINIPES HEMOLYMPH AFTER INFECTION WITH BEAUVERIA-BASSIANA OR WOUNDING

1. The phenoloxidase activity, protein and carbohydrate levels were studied for 24 hr in the hemolymph of the migratory grasshopper, Melanoplus sanguinipes after artificial wounding of the insect cuticle or the injection of Beauveria bassiana conidia. 2. Injection or wounding induced a primary response and phenoloxidase activity was found to increase within 10-60 min. The values for phenoloxidase activity in viable B. bassiana-injected insects exhibited a secondary response, i.e. an increase 24 hr after injection. 3. In wounded insects and those injected with inactivated conidia, the phenoloxidase activity receded after the initial increase and remained at low levels. 4. Protein concentrations in the hemolymph increased immediately after infection and wounding and returned to basal levels during the course of the experiment. 5. Injection of viable B. bassiana resulted in a gradual increase in the protein concentrations between 12 and 24 hr. 6. There was no apparent change in the carbohydrate levels in either B. bassiana-infected or wounded insects. 7. These results are discussed in relation to their possible role(s) and interrelationships in the immune response to infection or wounding. Furthermore, we suggest that a "factor" is released after mechanical injury of the integument.