| In recent years, the effects of elevated atmosphereic CO2on insect and the responses of insect to this change has become one of seriously concerned issues in the field of global warming. Elevated CO2concentration not only directly affect insect behavior, physiological and biochemical process from the respiratory system, but also indirectly affect the growth-development of herbivory insects by changing the plant nutrient content and chemical composition, and then through the food chain also affect the natural enemy insects. In this study, we had systematically examined the impacts of elevated atmospheric CO2(550μl/L and750μl/L) on the growth-development and reproduction of Ostrinia furnacalis, and the parasitic ability of Trichogramma dendrolimi in closed-dynamic CO2chamber and Open-top chamber, the results indicated:1. Effects of elevated atmospheric CO2on the growth-development of Ostrinia furnacalisElevated atmospheric CO2concentration significantly prolonged the larval and pupal development times of Asian corn borer in F0-F5generation exposed, the adult life was not affected. Along with the esposing generation increased, larval and pupal development times were reduced, suggesting the larvae and pupae evolved adaptability to elevated atmospheric CO2. Compared with ambient level, there were no significantly differences in larval and pupal weights in F0-F1under elevated CO2treaments, significantly reduced in F2-F5. This indicated that it resulted in reductions of larval and pupal weights for multigeneration selections under elevated CO2, i.e. the population evolved fitness cost elevated atmospheric CO2.2. Effects of elevated atmospheric CO2on the feeding of Ostrinia furnacalisElevated atmospheric CO2concentration urged the increasing of appetite and defecation of Asian corn borer, it was significantly increased in food consumption at generation FO and F5, but the frass significantly went up at every generation. Meanwhile, it was signicantly decreased for food approximate digestibility (AD), efficiency of conversion of ingested food (ECI), mean relative growth rate (MRGR) of Asian corn borer larvae at each generation under elevated atmospheric CO2, reduced for relative growth rate (RGR)at generation F1, F3and F5, and significantly increased for relative consumption rate (RCR) at generation F0, F2, F3and F4, and without significant different for efficiency of conversion of digested food (ECD) among all genegrations. It indicates that Asian corn borer may damage more to crop under elevated atmospheric CO2, because of decreased food utilization and increased food consumption.3. Effects of elevated atmospheric CO2on the population characteristics of Ostrinia furnacalisUnder elevated atmospheric CO2, there were more eggs laid per female at generation FO, F1and F3, and the larval mortality was increased. Meanwhile, it was significantly decreased in the net increment rate (R0), significantly prolonged the generation period, consequently, rm of population prominently reduced in each generation under elevated CO2levels. It indicated that it was not favorable the population development of ACB in the future under elevated atmospheric CO2.4. Effects of elevated atmospheric CO2on the parasitic ability of Trichogramma dendrolimiIn OTC, the ACB egg masses parasited rate by T. dendrolimi were reduced under elevaed atmospheric CO2, however, the ABC eggs parasited rate were increased under750μl/L, decreased under550μl/L. In the same atmospheric CO2level, the parasitism was significantly increased with the increasing number of T. dendrolimi released, but there was no significant difference in parasitism of eggs. In CDCC, it was not significantly impacted on the number of eggs parasite per female T. dendrolimi, emerging amount of offspring, the percentage of female in the offspring under elevated atmospheric CO2. Howeverand the eclosion rate was significantly reduced under elevated atmospheric CO2. |
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