28. Effects of Dietary Carotenoids on Carotenoid Sequestration by Trichoplusia ni

Abstract

Carotenoids are important to insects and their only source of carotenoids is through their diet. Little is known about how the amount of carotenoids in plants affect the amount absorbed by insects and how insects absorb carotenoids. The objective of this study is to evaluate how dietary carotenoids affect sequestration in hemolymph (blood) of the insect Trichoplusia ni. Larvae were reared on romaine lettuce (Lactuca sativa) or an artificial diet that provides no carotenoids, and will be reared on kale (Brassica oleracea var. sabellica) in the future. A spectrophotometer was used to measure carotenoids in hemolymph. High levels of carotenoids were found in romaine-reared larvae and none were found in the artificial diet. From the data, it is evident that carotenoids do accumulate in the hemolymph of larvae. To determine how Trichoplusia ni absorb/modify carotenoids, we plan to use protein electrophoresis to characterize the proteins involved. This research can show how carotenoids, which are nonpolar, are processed and stored in polar tissues of insects.