Changes in the free amino acids of the haemolymph of Antheraea pernyi during induction and termination of diapause

Abstract

Changes in the levels of haemolymph free amino acids were studied during the metamorphosis of a non-diapausing form and during the induction, maintenance, and termination of pupal diapause in a diapausing form of Antheraea pernyi. The levels of arginine, lysine, proline, and threonine increased gradually during metamorphosis; alanine and glutamine concentrations increased in the pupal stage before decrease during adult development, while glutamic acid decreased at the larval-pupal transformation before rising during adult development. The intervention of diapause resulted in increased levels of these amino acids (except glutamic acid) and histidine. Except for proline and histidine, the patterns of changes during metamorphosis in the levels of the affected amino acids were almost identical in both the non-diapausing and diapausing forms of the silkworm. Alanine and proline showed abnormal accumulation throughout the induction and maintenance of diapause before being depleted during post-diapause development. The increases in the levels of these amino acids appear to be secondary in nature, associated with physiological and biochemical adjustments during induction of diapause and cold-hardiness in A. pernyi.