21. The effects of the carotenoid β-carotene on the immune response of Trichoplusia ni

Abstract

Carotenoids are fundamental precursors for hormones and antioxidants, and insects must acquire carotenoids from their diet. Previous research has shown that insects often absorb carotenoids in amounts proportional to those in their diet, and that high-carotenoid diets are associated with strong immune responses. The objective of this study is to examine the effect that the carotenoid β-carotene on the immune response of Trichoplusia ni. To fulfill the objective, a low, medium, and high concentration of β-carotene, representing the range found in typical host plants, in an artificial diet will be used and immune response will be assessed in fifth instar larvae. Immune response will be induced by injection of chromatography beads in to the abdomen of the larvae. Encapsulation and melanization will be measured shortly after injection. We plan to use protein electrophoresis to assess protein expression associated with immune response. Evidence has shown that carotenoids can work in a synergistic way to improve the immune response, but there has been little work done to show the affect of individual carotenoids such as β-carotene on immune response. This research may show a link between carotenoid availability to insects and susceptibility to parasites and pathogens.