Induction of elastase in a zoophytophagous heteropteran, Lygus hesperus (Hemiptera : Miridae)

One potential biochemical adaptation to mired feeding habits, or zoophytoph agy, is enzyme induction/enzyme repression. We investigated the potential o f the highly polyphagous mirid Lygus hesperus Knight to increase its produc tion of the specialized proteolytic enzyme. elastase (E. C. 3. 4. 31.36). E fforts to induce elastase production were made by feeding L. hesperus on an artificial diet spiked with elastin. Short-term (less than one generation) and long-term (three generations) tests were conducted to determine the ef fect of acute versus chronic exposure to elastin, a protein chat may be pre sent in extra cellular matrix of prey. Elastase activity, was much greater in the salivary gland complex (SGC) of individuals fed elastin-containing d iet than it was in those fed the control diet. The elevated elastase activi ty in the elastin treatment group indicated the inducibility of this proteo lytic enzyme, especially in the SGC. The results also indicated that the SG C, rather than the gut, is the principal site of elastase production.