Study On Wing Development, Flight Muscle Degeneration And Interaction Between Macrosiphum Avenae (fabricius) And Wheat

Using ecological investigation methods and insect physiological technology, the wing development, degeneration and the mechanism of interaction between Macrosiphum avenae (Fabricius) and wheat are investigated. The main conclusions are as follow.(1) The effect of hosts on wheat aphid population paramaters. The resistant wheat varieties could inhibits effectively the development of aphid population, stimulate reproducing alate, decrease aphid's longevity and fecundity, extend nymph developmental duration. In addition, the antibiosis to aphid has cumulative effects as aphid generations continue. The EPG datas showed that the wheat variety has greater effect on aphid feeding. The effect of biochemical resistance was better than the effect of physical resistance. There was close relationship between number of aphid population and free amino acid of wheat by analyzing the content of free amino acid. The correlation was significant between number of aphid population and other 10 amino acid such as glycine, valine et al. The correlation was most significant between valine and aphid population. The content of free valine in wheat suggests the one of evaluation index of wheat resistance.(2) Adaptive strategies of wheat aphid to wheats. Aphid population has certain adaptability to the changing environment. When alate aphid was allowed to settle down their host pants, their flight muscles began to break down within a few days. Flight muscle degeneration obliged aphid to decrease the number of flight and save much energy for fecundity. In new habitate, the aphid burns a plenty of apterous aphid. The number of aphid population peak stage when aphid colonized new habitate after a month. The aphid burns alate nymph in order to find new habitate when the host plants mature. The emergence of alate and emigration of aphid avoid the aphid population's extinction for lacking food. The results show that feeding resistante wheat of aphid will burn more alate nymph to leave the host palnt. In the aphid population, the proportion of red bodycolor aphid increased with the growth stage of hosts..(3) Morphological and histological examination of aphid wing formation. The wing dimorphism took place in 2nd instar. Both the wing types have wing primordia before 2nd instar. The primordia gradually atrophy until complete disappearpance from 2nd instar to 4th instar in the wingless aphid. The primordia gradually develop into wing from 2nd instar to 4th instar in the alate aphid. The external factors had an effect on aphid wing formation. The wing formation is controlled by mother aphid living environment.(4) Mechanisms of histolysis in indirect flight muscles of alate aphid. The research results showed that the histolysis of flight muscles was induced by muscular cell apotosis. The muscular cell apotosis was an active physiological response of aphid. In mormal feeding condition, the cell of flight muscle began apotosis at 7-day adult. Flight muscle began atrophy at 9-day adult. The histolysis of flight muscle was complete at 13-day adult. Feeding was one of the main factors which has quiet an effect on the histolysis of flight muscle. When alate aphid was kept off the host pant after the final ecdysis, the breakdown of their flight muscles was prevented, and few larvipositions followed.