Analyses of the stomach deposit that develops in Myzus persicae feeding onsugar beet

The white deposit, commonly found in the stomach of aphids that feed on sug ar beet (Beta vulgaris ssp. saccharifera L), turns a dark colour just prior to the death of the aphid, suggesting that chemical changes causing the de posit to darken may be associated with the death of the aphid. Chemical ana lyses of the white and dark stomach deposits by HPLC after hydrolysis, elem ental analysis and FAB-MS, showed that the dark deposit is formed after the loss of hydrogen and oxygen from the organic white deposit, and that it ap pears to be a complex that is not dominated by any given compound. These re sults contrast with those of:previous studies, in which the white precipita te was described as a polysaccharide or a mucopolysaccharide.