Characterization of digestive proteases and glycosidases in Lucilia eximia (Diptera: Calliphoridae) larvae: Insights into Dipteran enzymatic processes

Abstract

Larvae of Lucilia eximia typically cause secondary myiasis, although they may induce primary myiasis in cats, dogs, and rabbits, possibly transitioning to strict parasitism. To gain a deeper understanding of its physiology larvae were fed with pH indicator dyes mixed with fresh fish to determine the pH of each region of the digestive tract. Glycosidase and protease activities were assessed in homogenates prepared from salivary glands and sections of the digestive tracts of third instar larvae. Excreted/secreted products were extracted from larval-digested fresh fish. Trypsin was the only protease detected in the midgut, absent in salivary glands. Predominant glycosidases identified were α-D-mannosidase and α-D-glucosidase, showing high activity in the midgut and only trace amounts in salivary glands. Lysozyme activity was high in the midgut but low in salivary glands, diverticulum, and excreted/secreted products. This study identifies the major digestive enzymes of L. eximia larvae.