Effects Of Elevated CO₂ On The Interaction Of Sitobion Avenae-Aphidius Gifuensis

The concentration of greenhouse gases in the atmosphere has been shown a significant upward trend in recent years,among which the increase of CO₂ has a great impact on the global climate.The effects of increase of atmospheric CO₂ concentration on the parasitic insects and their hosts is closely related to human agricultural production activities and has been a hotspot of extensive research in recent years.By revealing the effects of increase of atmospheric CO₂ on the interaction of " Sitobion avenae-Aphidius gifuensis " system,the occurrence trend of S.avenae under the increase of CO₂ and the prevention and control efficiency of A.gifuensis as natural enemies of life and control can be predicted.It is of great significance to improve the accuracy of forecasting and scientific application of parasitic natural enemy prevention and control decisions.In this paper,two treatments of high CO₂?800ppm?and standard CO₂?400ppm?were set.By performing two concentrations of CO₂ treatment?1?weight and population dynamics of S.avenae?2?parasitism rate,emergence rate,female ratio,life span,development time and fecundity of A.gifuensis?3?Studies on host preference of A.gifuensis for for CO₂ treatment.The results as follow:1.The effect of CO₂ elevation on the population and weight of S.avenae were tested in the CO₂ artificial incubator.The results showed that the elevated of CO₂ had a significant effect on the population of S.avenae.The offspring of S.avenae increased significantly under high CO₂ treatment.There was no significant effect on the weight of winged,adults and nymphs of the S.avenae.2.The effect of elevated CO₂ on the development and reproduction of the wasp was carried out in CO₂ artificial incubator.The elevated of CO₂ reduced the fecundity?the number of wasps under the high CO₂ was 161 � 9.80,and the standard CO₂ was 281 � 26.63?,parasitism rate?57.54 � 0.02 % under high CO₂ concentration,78.80 � 0.03 % under standard CO₂ concentration?,emergence rate?73.06 � 0.05 % under high CO₂ concentration,74.57 � 0.07 % under standard CO₂ concentration?of the A.gifuensis,while the proportion of females in offspring was increased?31.19 � 2.28 % under high CO₂ concentration and 48.10 � 3.56 % under standard CO₂ concentration?,the developmental period shortened?15.02 � 0.21 d under high CO₂ concentration,15.99 � 0.11 d under standard CO₂ concentration?,and the life span of females in the offspring increased?14.0 � 0.37 d under high CO₂ concentration and 11.5 � 0.43 d under standard CO₂ concentration?.3.The "Y"-type olfactory instrument was used to evaluate the effect of elevated CO₂ on host selection of A.gifuensis.The results of olfactory reaction showed that increased CO₂ concentration significantly enhanced the preference of A.gifuensis to host.Compared with the wheat,S.avenae and S.avenae /wheat complex treated with standard CO₂ concentration,the wheat,S.avenae and S.avenae /wheat has a significantly inducement of A.gifuensis under high CO₂ concentration.