Bioamines and proteins in the saliva and salivary glands of Palaearctic blackflies (Diptera: Simuliidae).

To elucidate the mechanisms of skin-reactions to blackfly bites, components in the saliva and salivary glands of Simulium lineatum and S. equinum females were studied. Histamine, putrescine, spermine, N1-monoacetyl-spermine, and spermidine were detected in both the saliva and salivary gland extract through high-performance liquid chromatography (HPLC), the content of histamine being much higher than that of the other amines. Whereas histamine concentration was increased by food stimulation and actual feeding, the content of the other amines did not differ from that of non-stimulated flies. S. lineatum and S. equinum females differed significantly in their spermine and spermidine contents, autumn and spring generation females did not differ from each other. The dispersion of histamine in the salivary glands of male and female S. lineatum and S. equinum was demonstrated through histochemical staining. The globular proteins of the salivary glands were fractionated by chromatography and electrophoresis, the molecular weight of proteins and the enzymatic activity of esterase were also determined.