Date of Award:

5-1-1972

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Biology

Department name when degree awarded

Zoology (Entomology)

Committee Chair(s)

Ting H. Hsiao

Committee

Ting H. Hsiao

Committee

William A. Brindley

Committee

Thomas M. Farley

Abstract

Amino acid and protein metabolism were studied during growth and development of the alfalfa weevil. The amino acids were separated and identified by two-dimensional thin layer chromatography on cellulose plates and quantitative determinations were made with a ninhydrin spectrophotometric method. The radioactive isotope glucose-U-C14 was used to determine amino acid requirements and their rates of synthesis. A total of 23 amino acids were identified in the fourth instar larvae. Of these, 21 were free amino acids and 17 were protein amino acids. Limited concentrations of methionine, Y-aminobutyric acid and tryptophan in the insect were directly correlated with their dietary source of alfalfa. Total free amino acid concentrations remained constant throughout development suggesting the existence of some means of their metabolic control. The free amino acids found in greatest concentrations were proline, glutamine, aspartic acid, arcinine and histidine. The predominant protein amino acids were alanine, aspartic acid, glutamic acid, lysine and serine. Lysine, histidine, arginine, valine, threonine, isoleucine, phenylalanine, methionine and leucine appear to be dietary requirements. Adult females reared under short-day photoperiod (non-diapausing) and long-day photoperiod (diapausing) showed similarities in food consumption, protein amino acid concentrations and incorporation rates of the radioactive isotope. The results suggest that there is no difference in amino acid and protein metabolism between the diapause and non-diapause adult during the first 40 days of adult growth. Protein amino acid concentrations corresponded with the growth of the insect in terms of food consumption. Both food consumption and total protein amino acid concentrations declined after the third week of adult life.

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