Ecological aspects of digestive enzyme covariation in almond moth larvae, Ephestia cautella (Walker) (Lepidoptera, Phyticidae)

In this paper we examine the correlations between activity levels of several digestive enzymes measured simultaneously in larvae of the almond moth, Ephestia (=Cadra) cautella (Walker). This study is unique in that we measured enzyme activity in each individual larva, not in samples pooled from several individuals as is the usual procedure in physiological studies of insects. This enabled us to take individual variation in size and enzyme activity into consideration and to calculate the correlation between different enzymes. We demonstrate that inter-enzyme correlations are affected by the diet on which the larvae feed.

In most of the research on insect digestive physiology, investigators have concentrated on a single enzyme. But in the insect alimentary canal, different enzymes do not work in isolation. We demonstrate some patterns of activity correlations of different enzymes measured in extracts from the same individual larva which may suggest possible mechanisms of enzyme activity regulation.