Cuticular Plasticization Induced by Injection of Synganglion Extracts, Haemolymph or Biogenic Amines in Virgin Female Haemaphysalis longicornis(Aeari: Ixodidae)

Abstract

Synganglion extracts from5-day fed non-copulated females or haemolymph from5-day fed copulated females were injected into the haemocoel of partially engorged virgin females, and physiological saline was subsequently infused into the haemocoel at 150 mmHg for 48hours. These components, the extract and thehaemolymph, induced cuticular plasticization or>10-fold increase in relative body volume.Protease digestion did not prevent these components from inducing cuticular plasticization. Biogenic amines, octopamine and noradrenaline(≥10^-6 M in the haemolymph), also induced cuticular plasticization. These results suggest that a neurohormonal factor inducing cuticular plasticization is released from the central nervous system into the haemolymph after receiving copulatory stimuli.