Some

larval insects such as mosquitoes and some caterpillars are known to possess a highly alkaline digestive system (Dadd, 1975). Berenbaum’s review (Berenbaum, 1980) of Lepidopteran insects reported gut pH values ranging from 7.0 to 10.3, through the influence of diet. Caterpillars feeding on leaves containing tannins were found to display a more alkaline pH (average pH·8.76) than those feeding on low tannin diets (average pH·8.25; Berenbaum, 1980). The alkaline gut is believed to disrupt and inhibit the formation of insoluble tannin–protein complexes. These complexes could potentially interfere with insect digestion by blocking the active sites of many different digestive enzymes. Therefore, the alkaline gut serves as a hypothetical benefit to the larval insects by solublizing proteins in a tannin-free form. The advantage of the alkaline digestive strategy is clear; however, the mechanism o