none Mythimna separata; BIOCHEMISTRY-; Amines; PROTEINS-; Aromatic amino acids, haemolymph levels; HAEMOLYMPH-; Aromatic amino acid & amine levels; HYMENOPTERAN-PARASITES; Apanteles kariyai; Haemolymph amino acid & amine levels, parasitized & unparasitized larvae Apanteles kariyai; LEPIDOPTERAN-HOSTS; Mythimna separata; Haemolymph amino acid & amine levels, parasitized & unparasitized larvae The levels of aromatic amino acids and amines in the hemolymph of larvae of the common armyworm. Mythimna separata, were analyzed after parasitization by the braconid wasp, Apanteles kariyai. Methyldopa, homovanillic acid, tryptophan and tyrosine remained unchanged in unparasitized and parasitized larvae. Dopamine and DOPA showed characteristic changes at pupation that were associated with the hardening and darkening of the cuticle; Dopamine in the hemolymph of unparasitized last instar larvae increased before pupation. Large increases in kynurenine and octopamine were detected in parasitized larvae. The increased level of octopamine in the hemolymph may be stress related.