The Effects Of Sublethal Concentrations Of Insecticides On The Reproduction Of Cyrtorhinus Lividipennis

Cyrtorhinus lividipennis(Reuter)(Hemiptera:Miridae)is an important predatory in the rice paddy.It mainly feed on the eggs and young nymphs of brown planthopper(Nilaparvata lugens),white-backed planthopper(Sogatella furcifera Horvath),and green leafhoppers(Nephotettix virescens Distant).In this study,five insecticides(Triazophos,Deltamethrin,Imidacloprid,Pymetrozine,Chlorantraniliprole)were selected to study the effects of their sublethal concentration LC20 on C.lividipennis.The complete cDNA sequences and relative expressions of genes encoding spermatogenesis-associated protein 13 were examined.The sublethal effects of five insecticides on the reproduction and population growth of C.lividipennis were investigated.The results were as follows:(1)The complete cDNA sequences gene encoding spermatogenesis-associated protein 13 was obtained by reverse transcription polymerase chain reaction(RT-PCR)with rapid amplification of cDNA ends(RACE).The full-length sequence of spermatogenesis-associated protein 13 gene(Gene name:CISPATA13)was 4509 bp.The full length nucleotide sequence was submitted to the NCBI GenBank database under accession number KU365919.The ClSPATA13 gene was quantified by SYBR Green I chimeric fluorescence method.The result showed the expression level of CISPATA13 was significantly up-regulated in triazophos,deltamethrin,imidacloprid,pymetrozine,chlorantraniliprole,and the relative expressions of CISPATA13 increased by 80.7%,40.9%,47.8%,84.7%,53.3%,respectively.(2)In this paper,third-instar nymphs of C.lividipennis,were exposed to sublethal concentrations(LC20)of five insecticides(triazophos,deltamethrin,imidacloprid,pymetrozine and chlorantraniliprole)by pesticide-membrane method.The sublethal effects of five insecticides on the reproduction and population growth of C.lividipennis were investigated.Our results showed that sublethal concentration of five insecticides did not have effects on the pre-oviposition period and egg hatchability of the different mating pairs of C.lividipennis(?c×?t??t×?c??t×?t),compared to the control(?×?c).However,the number of eggs of C.lividipennis exposured to five insecticides was significantly higher than control.Triazophos treatments significantly influced.The numbers of eggs laid for the controll(?c×?c)was 66.6±3.6.however,different mating pairs(?c×?t??t×?c??t×?t)of C.lividipennis that treated with the LC20 concentration of triazophos were 102.5 ± 7.4?97.5 ± 5.7?101.0 ± 7.2,increasing by 53.9%,46.4%and 51.7%,respectively.Thie trend was also observed at the LC20 for deltamethrin,imidacloprid,pymetrozine and chlorantraniliprole.For triazophos,the population insecticides for three pair combinations(?c×?t??t×?c??t×?t)were significantly higher than untreated pair(?c×?c)and showed a 63.6%,81.3%and 90.9%increase,respectively.This trend was also observed at the LC20 for imidacloprid,pymetrozine and chlorantraniliprole.Deltamethrim caused a significant increase in population numbers for treated pair combination(?t×?t),but not the other pair combinations.