An investigation of insect eggshell using fourier transform infrared spectroscopy

The moth Helicoverpa amigera is a major agricultural pest. The use of parasites such as wasps from the genus Trichogramma is a promising pest control strategy. H, amigera eggs exposed to this parasite undergo a colour change clue to the deposition of a dark; layer of material on the vitelline membrane. FT-IR analysis of spectra from this layer reveals that the deposit is proteinaceous. The location of the amide bands suggests that the secondary protein structure consists of beta-turns, alpha-helis and irregular structures. There is evidence of oxidation changes to cystine residues due to an inflow of atmospheric oxygen during the development of the parasite. Absence of characteristic bands indicates the deposit is not melanotic.