| Frankliniella occidentalis is one of the most important pests infesting agricultural and horticultural crops worldwide,and a national-and international-wide important quarantine pest.F.occidentalis has two races,i.e.,greenhouse race?GR?and lupin race?LR?.There are significant differences between the two races in host plant species,pesticide resistance,living environments,etc.However,it is difficult to identify these two races because of their high similarity in morphological characteristics.Moreover,the reproductive isolation and ecological adaptability of both races are not clear.It is important to clarify the above information for the targeted prevention and control of F.occidentalis.In this study,a one-step,single tube,duplex PCR procedure for rapid identification of F.occidentalis greenhouse race and lupin race was developed by using species-specific COI?SS-COI?marker based on mitochondrial DNA cytochrome c oxidase subunit I?mtDNA COI?gene.The reproductive biology characteristics and ecological adaptability of the two races were studied under lab conditions.The main results are as follows:?1?One-step duplex rapid identification technique of F.occidentalis greenhouse and lupin races based on species-specific COI marker.The race-specific primer combination system?TF6/GR32/LR12?was established according to the COI sequences of F.occidentalis greenhouse and lupin races and other14 thrips species common in the field.The fragments amplified by the combined primers are 362 bp for greenhouse race and 541 bp for lupin race,respectively.When the ratios of the combined primers?TF6/GR32/LR12?were 1.0/0.2/0.8 and the annealing temperature was 44°C,the system works well.The combined primer set has strong specificity and only the F.occidentalis greenhouse race and/or lupin race specimens could be detected positively.The system was applicable for every developmnent stage of greenhouse and lupin races of F.occidentalis,either in single race or two races mixed together.Furthermore,target to the greenhouse race,the detection threshold was 35.90 pg·?L-1,target to the lupin race,that was 146.95 pg·?L-1.The one-step duplex PCR system developed here for rapid identification of F.occidentalis greenhouse and lupin races could be significant in blocking further spreading and developing targeted prevention and control measures of F.occidentalis.?2?Characterization of reproductive biology of F.occidentalis greenhouse and lupin race.The hybridization experiments of induviduals and communities were performed respectively.We recorded the longevity of female and male adults,fecundity,female proportion of F1 generation,survival rate of hybrid combinations,and the fertility of hybrid F1 generation.The results demonstrated that no reproductive isolution was detected.The results clearified the taxonomic status of the two races,indicating that F.occidentalis greenhouse race and lupin race are the same species.?3?Population stabilization mechanism of high female proportion in F.occidentalis greenhouse and lupin race.The stability mechanism of populations established by various numbers of vergin females had been observed,and the population dynamics and female proportion had been investigated.Our results showed that the female proportion was kept over 70%and further experiments demonstrated that parthenogenetic female could mate with gender male and generate offsprings.Single male c ould mate with 1-6 female individuals within 24 h showing that male has the characteristics of multiple mating.The multiple mating behavior of the males could play an important role in maintaining the high female proprotion of F.occidentalis population.The present results will benefit in researching of population maintenance mechanism of other species and the population managemnent of the western flower thrips.?4?Competition between populations of F.occidentalis greenhouse and lupin races.The competition and biological characteristics of the two races of F.occidentalis was compared under three different temperature and humidity combinations?low temperature and high humidity,optimum temperature and humidity,and high temperature and low humidity?in view of the uneven distribution of the two races of F.occidentalis in the wild,that maybe related to the different adapbitilities to temperature and humidity conditions of the two races.The competitive results indicated that lupin race was more competitive than the greenhouse race under the three conditions with different population ratios.There was no significant difference in the development period of the two races under the tested three temperature and humidity combinations,but the fecundity of lupin race was higher than that of greenhouse race.In general,the lupin race has a wider range of ecological adaptation,higher fecundity and stronger population competitiveness.The results are helpful for prediction of the appropriate area of two races of F.occidentalis and the development of targeted prevention and control measures. |
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