Effects of Dietary Protein and Protease Inhibitors on Codling Moth (Lepidoptera: Tortricidae)

Abstract

A linear relationship was found between mean larval weight gain and dietary casein levels in the codling moth, Cydia pomonella (L.). When protease inhibitors were added to artificial diets, the effects on growth rate of codling moth larvae were more pronounced where the dietary casein level was higher. Potato proteinase inhibitor 1 was the most effective single proteinase inhibitor in reducing growth rate, followed by soybean trypsin inhibitor. However, the most significant reductions in growth rate occurred with larvae fed diets containing a combination of potato proteinase inhibitor 1 and carboxypeptidase inhibitor. Predominant larvae gut proteolytic activities were elastase like endopeptidase activity and leucine aminopeptidase. Larvae that had chronically ingested the elastase inhibitors potato proteinase inhibitor 1 and eglin C, or combinations of protease inhibitors that included potato proteinase inhibitor 1, showed significantly lower elastase like activity.