Differences in amino acid requirements between two biotypes of the pea aphid, Acyrthosiphon pisum

Abstract

Amino acid requirements of two biotypes (C and J) of the pea aphid, Acyrthosiphon pisum (Harris), were studied by deleting single amino acids from a chemically defined liquid diet. Amino acids found to be essential for growth and (or) reproduction of biotype C were arginine, histidine, leucine, lysine, methionine, threonine, and tryptophan, and for biotype J, histidine, methionine, phenylalanine, threonine, and valine. Two generations were needed on deficient diets to demonstrate the essentiality of some of the amino acids. This appears to be a rare example of two insect populations within one species differing in their amino acid requirements. It is suggested that intracellular symbiotes play a major role in supplying the aphids with missing amino acids.