The Increasing Temperature Accelerated the Population Growth of Rhopalosiphum padi and Sitobion avenae by Wheat Rhizosphere Microorganisms
[Objective]Climate warming can affect the occurrence and damage caused by wheat aphids.Rhopalosiphum padi and Sitobion avenae as the main pests of wheat in the Huang-Huai-Hai region of China,their population development and reproduction are affected by warming.This study aims to investigate whether climate warming will change the wheat rhizosphere microorganisms,which would indirectly affect the development and reproduction of R.padi and S.avenae.[Method]At the Yuanyang experimental station in Henan Province,infrared radiation heaters were hung to simulate a temperature increased by 2℃,and the number of wheat aphids occurring was investigated after the wheat returned to the greening stage.During the wheat jointing stage,rhizosphere microorganisms were collected and then brought to the laboratory to obtain the mixed microbial solution.The population dynamics and age-stage two-sex life table of two aphid species were tested by irrigating wheat with mixed solution.The mixture of rhizosphere microorganism was irrigated,and then aphids were inoculated.The number of aphids was recorded after 5 consecutive observations.For life table experiments,individual aphid of two wheat aphid species was fixed onto the 2nd leaf of wheat using ecological boxes,and the molting,instar and mortality of nymphal aphid were observed and recorded every day.At the same time,the reproduction and mortality of adult aphid were also recorded.[Result]Under different treatments,the population dynamics of R.padi and S.avenae were increasing continuously.With increasing investigation frequency,the increase of aphids gradually increased with irrigating the rhizosphere microorganisms of the elevated field compared with that at the ambient field.Rhizosphere microorganisms in the elevated field significantly increased the total mean number of R.padi and S.avenae,and compared with S.avenae,the increase of R.padi was greater,which increased by 4.49 times of S.avenae.The results of the population life table showed that the rhizosphere microorganisms in the elevated field significantly shortened the mean generation time,population doubling time,preadult duration,and oviposition duration of R.padi,while significantly increasing its intrinsic rate of increase,finite rate of increase and offspring.In addition,rhizosphere microorganisms in the elevated field significantly improved the survival rates of S.avenae at all developmental stages.[Conclusion]Warming promotes the growth,development,and reproduction of R.padi,enhances the survival rate of S.avenae,and accelerates the population growth of both aphid species,respectively,by affecting rhizosphere microorganisms,which may lead to changes in the migratory behavior of the aphids.These findings provide initial insights into the outbreak mechanism of wheat aphids under climate warming,and offer valuable references for predicting and assessing wheat aphid occurrences under future climate warming.
climate warmingrhizosphere microorganismwheat aphidlife tablepopulation development
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