At the present paper,adult populations of the psocid, Liposcelis bostrychophila ,were exposed respectively for 30 generations to two atmospheres containing 0 5% and 1% O 2 (N 2 in mixture as balance),in order to...At the present paper,adult populations of the psocid, Liposcelis bostrychophila ,were exposed respectively for 30 generations to two atmospheres containing 0 5% and 1% O 2 (N 2 in mixture as balance),in order to select strains resistant to low O 2 content (LOC) atmosphere.Selection pressure was maintained at around 70% mortality.At the 30th generation,comparison of sensitivity between the selected strains (LOC1 and LOC2) and the original susceptible strain (CA S) indicated a tolerance factor (TF) at the 50% mortality level (LT 50 ) of 4 7 and 3 9 fold,respectively.Throughout the selection process,log time against probit mortality lines remained roughly parallel and the slopes remained lower than that of CA S strain until the last generation.The implication is that at high level of selection,multiple genetic factors continued act together even at the 30th generation to select for adaptation to survival at depleted O 2 concentration.Up to 30th generation,two selected strains still possessed the genetic potential to develop resistance to LOC.Removal of selection pressure for 5 generations from 2 sub populations of two selected strains from 25th generation caused significant reduction in resistance.In the absence of CA exposure,the two selected strains all possessed the reproductive disadvantages or fitness defect.LOC1 and LOC2 were calculated by R 0 to have a fitness value of 0 56 and 0 75 relative to unselected strain,respectively.展开更多
The cross resistance of four resistant strains of Liposcelis bostrychophila Badonnel, an important stored-product insect pest, was investigated. These four strains included the HCO2-R (hypercarbia-resistant strain),...The cross resistance of four resistant strains of Liposcelis bostrychophila Badonnel, an important stored-product insect pest, was investigated. These four strains included the HCO2-R (hypercarbia-resistant strain), HCLO-R (hypoxia and hypercarbia resistant strain), DDVP-R (DDVP-resistant strain) and PH3-R (PH3-resistant strain). The results indicated that there were cross-resistances between CA and insecticides, and the quantities of the cross-resistance were different. The cross-resistance factor (RF) of HCO2-R to hypoxia and hypercarbia was 3.2458, whilst, that of HCLO-R to hypercarbia was 1.8280. The RF of DDVP-R to PH3 was 3.9614, whilst, that of PH3-R to DDVP was 2.7852. The RF values of DDVP- R and PH3-R to hypercarbia were 1.3550 and 1.1816, respectively. However, the RF of HCO2- R to DDVP was 2.1372. There also was a low cross-resistance between DDVP-R and HCO2-R. The RF of HCO2-R to PH3 was 3.3698. This suggested that the insects resistant to high CO2 concentration atmosphere would develop significant resistance to PH3. However, the insects resistant to PH3 remain sensitive to hypercarbia atmosphere. Both DDVP-R and PH3- R developed resistance to high CO2 treatment. There was a low cross-resistance between DDVP-R and HCLO-R. The insects resistant to hypoxia and hypercarbia were very sensitive to DDVP. There also was cross-resistance between HCLO-R and PH3-R, but the resistance of PH3-R to hypoxia and hypercarbia was lower than that of HCLO-R to PH3. The difference of the overlapping and separate values indicated that there were differences in the intercross-resistance of four resistant strains.展开更多
文摘At the present paper,adult populations of the psocid, Liposcelis bostrychophila ,were exposed respectively for 30 generations to two atmospheres containing 0 5% and 1% O 2 (N 2 in mixture as balance),in order to select strains resistant to low O 2 content (LOC) atmosphere.Selection pressure was maintained at around 70% mortality.At the 30th generation,comparison of sensitivity between the selected strains (LOC1 and LOC2) and the original susceptible strain (CA S) indicated a tolerance factor (TF) at the 50% mortality level (LT 50 ) of 4 7 and 3 9 fold,respectively.Throughout the selection process,log time against probit mortality lines remained roughly parallel and the slopes remained lower than that of CA S strain until the last generation.The implication is that at high level of selection,multiple genetic factors continued act together even at the 30th generation to select for adaptation to survival at depleted O 2 concentration.Up to 30th generation,two selected strains still possessed the genetic potential to develop resistance to LOC.Removal of selection pressure for 5 generations from 2 sub populations of two selected strains from 25th generation caused significant reduction in resistance.In the absence of CA exposure,the two selected strains all possessed the reproductive disadvantages or fitness defect.LOC1 and LOC2 were calculated by R 0 to have a fitness value of 0 56 and 0 75 relative to unselected strain,respectively.
基金funded in part by the Nationa1 Natura1 Science Foundation(38800017)of ChinaFok Ying-Tung Education Foundation(71022).
文摘The cross resistance of four resistant strains of Liposcelis bostrychophila Badonnel, an important stored-product insect pest, was investigated. These four strains included the HCO2-R (hypercarbia-resistant strain), HCLO-R (hypoxia and hypercarbia resistant strain), DDVP-R (DDVP-resistant strain) and PH3-R (PH3-resistant strain). The results indicated that there were cross-resistances between CA and insecticides, and the quantities of the cross-resistance were different. The cross-resistance factor (RF) of HCO2-R to hypoxia and hypercarbia was 3.2458, whilst, that of HCLO-R to hypercarbia was 1.8280. The RF of DDVP-R to PH3 was 3.9614, whilst, that of PH3-R to DDVP was 2.7852. The RF values of DDVP- R and PH3-R to hypercarbia were 1.3550 and 1.1816, respectively. However, the RF of HCO2- R to DDVP was 2.1372. There also was a low cross-resistance between DDVP-R and HCO2-R. The RF of HCO2-R to PH3 was 3.3698. This suggested that the insects resistant to high CO2 concentration atmosphere would develop significant resistance to PH3. However, the insects resistant to PH3 remain sensitive to hypercarbia atmosphere. Both DDVP-R and PH3- R developed resistance to high CO2 treatment. There was a low cross-resistance between DDVP-R and HCLO-R. The insects resistant to hypoxia and hypercarbia were very sensitive to DDVP. There also was cross-resistance between HCLO-R and PH3-R, but the resistance of PH3-R to hypoxia and hypercarbia was lower than that of HCLO-R to PH3. The difference of the overlapping and separate values indicated that there were differences in the intercross-resistance of four resistant strains.
