Studies On The Characters Of Physiology And Biochemistry About Wheat Aphid Migration

This thesis dealt with the flight activity of grain aphid Sitobion avenae (Fabricius), ultramicro structure of flight muscle in grain aphid and bird cherry oat aphid Rhopalosiphum padi (Linnaeus), enzymes special activities of intimative flight behavior and the JH(s) titer of different developing stages in Rhopalosiphum padi. The main results were as follows:1. The flight activity of Sitobion avenae was monitored by a micro-flight-mill system at several temperature grades (12℃ - 30℃ ). The results showed that the flight speed accelerated with increase temperature. There were two temperature zones - the optimal temperature zone 12℃ - 22℃ , the high temperature zone 25℃ and above. The average longest flight duration and the maximum fight distance were 3.101h and 3.676km at 18℃ , the fastest average speed was 1.357km/h at 30℃ .2. The ultrastrucure of indirect flight muscle of Rhopalosiphum padi was detected under electronic microscope. It was found that the myofibril and mitochondria of flight muscle became disordered after Rhopalosiphum padi flighted 8~12h comparing with non-flight aphid. The sarcomere lessened from 3.26u m to 2.94 u m, the section of flight muscle appeared cavities. The ultrastrucutre of the indirect flight muscles of Sitobion avenae showed that there were the longer sarcomere (3.84um) and the less mitochondria in the section than Rhopalosiphum padi. The length of sarcomere has closely relationship of the flight speed. The longer the sarcomere , the slower the flight contraction. That' s maybe the physiological basis why Sitobion avenae with lower flight activity than that of Rhopalosiphum padi3. It was measured the special activities of glyceraldehydes-phosphate dehydrogenase (GAPDH), glycerol-3-phosphate dehydrogenase (GDH), lactate dehydrogenase(LDH), 3-hydroxyacyl-CoA dehydrogenase (HOAD) and citrate synthase(CS) in the 4th instar and different adults of Rhopalosiphum padi. The level of Glycolytic acivities and lipid metabolism showed that GAPDH and HOAD keep up high activity during the 1~5 days in adult aphid age. The wheat aphids have strong flight ability at the same time, which suggests higher energy metabolism coincide with higher flight activity. The ratios of GAPDH:HOAD , GAPDH:CS and HOAD:CSindicated that both lipid and carboghydreate could be utilized as energy substrates during sustained flight of aphid.We made conclusions from the special activities of GDH and LDH. The conclusions were that the bird cherry oat had slighter metabolic capability without oxygen. However, the insect can provide energies if it is necessitous.4.The titer of juvenile hormone (JH) of various developmental stages apteral and alate Rhopalosiphum padi were detected by high performance liquid chromatography (HPLC). There were JH I ,JH II and JHIII. In the adult only JHIII was detected. The JH titers had huge fluctuation with variance analysis in different stages. The parent generation has significantly greater effect on the descendant.