Effect Of C And N Elements Contents Changing In Herbage On Oedaleus Asiaticus Feeding

Control of Locust has become a major strategic target of balance maintenance ofgrassland ecological system. Nitrogen and phosphorus is one of the many elements oforganisms and an important component of various proteins and genetic material,Carbon is a variety of physiological and biochemical process in plants of the substrateand energy sources through photosynthesis. Nitrogen is considered to be the mostimportant limiting factor for herbivorous insects. But some scholars hold that:phosphorus is not limiting factor as same as nitrogen. Along with the establishmentand development of chemometrics, new ideas for the locust control has been putforward: by means of artificial fertilization change C, N, P content of elements inforage grass. On one hand, recovery soil fertility which is decline caused byover-grazing and the locusts pest; on the other hand, changing diet rules and habits ofgrasshoppers, in the end reach the control of locusts pest. On the basis ofdetermination of C, N element content, Food selection frequency and food intakeamount of5th instars stage larva and adult individuals of Oedaleus asiaticus weremensurated by means of artificial feeding on un-fertilization(ON) forage, nitrogenousfertilizer (HN) forage, phosphate fertilization(P) forage,nitrogenous and phosphatetogether(N+P) fertilizer forage of Leymus chinensis and Stipa capillata. The results ofanalysis of elements shows that: The N content of Leymus chinensis is higher thanStippa capillata, applying N fertilizer can significantly increase the Ncontent,whatever using any fertilizer,C elements will be maintained at a relativelystable level. The P element changes will not interfere with N absorption of plant.C:Nof forage is little difference by means of different fertilizer. O.asiaticus feedingLeymus chinensis and Stipa capillata on different fertilizer:ON or HN by ourexperiment in2011and2012. It shows that: in5th instars stage, the N elementscontent in food could meet the development and growth needs of O.asiaticus becauseof the total feeding amount is very low, so N content in food is not importantly limitedfactors of feeding selection and food intake amounts,5th instar grasshoppers have notobviously selective behavior and food intake difference between L. chinensis and S.capillata or for each plant between higher and low N content. But in adult stage, O.asiaticus, especially the males individuals are more interested in low N content plantor S. capillata. The total results implied that the selective frequency and food intakeamounts of O. asiaticus on L. chinensis and S. capillata at higher or low Nfertilization could be adjusted according to developmental stage and sex and Ncontent of food. However, O. asiaticus was a low N content plant preferencegrasshopper in it’s historical evolution process. We add a P element as the interferencefactors in2012, on the basis of comparison of O.asiaticus feeding on Leymuschinensis and Stipa of using P(or N+P) fertilizer,we design intake amount andselection of O. asiaticus feeding on different fertilization food of Leymus chinensis(orStipa). Due to the need for more nutrients, more P elements in the locust growth canincrease feed intake, Improve the selection frequency of low N food. However, theweak effect of P elements on feeding，so P is not the limiting factor.