| Abstract: | Abstract The ecdysteroids (ECs) concentration and their components in the larvae of Haemaphysalis longicornis were determined by radioimmunoassay (RIA) and high performance liquid chromatography (HPLC). ECs ware found in feeding and engorged larvae and absent in unfed larvae. During feeding and the first 3 days after engorgement, ECs were in low level (less than 14. 35pg EE /larva). On the 5th day, they began to increase sharply (29. 87pg EE /larva) and reached their peak (56. 04pg EE /larva) on the 7th day. Then they declined to low value again (19. 38pg EE /larva). HPLC analysis revealed that the ECs components of the RIA peak could be 20-hydroxyecdysone (20E) and ecdysone (E) on the ratio of 20E: E = 3. 07: 1, which meant 20E was probably the main effective hormone. |
