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Background: Recent reports have suggested that different symbionts of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) have differential susceptibility to antibiotic treatment. Changes in the community structure of B. tabaci-associated bacterial microbiota (BABM) following antibiotic treatment, however, remain poorly understood, although increasing numbers of B. tabaci-associated bacteria have been reported in recent years., Methodology and Results: The BABM of male or female B. tabaci Q (also known as B. tabaci MED species) were analyzed after being fed on artificial diet containing the antibiotic rifampicin and compared with untreated controls. The bacterial 16S rDNA gene amplicon metagenomic sequencing method was used in the analyses. The results showed that the BABM in male and female adults have different characteristics, and that the community structure of the BABM changes drastically following antibiotic treatment. Further analysis of the endosymbionts in B. tabaci showed that the relative abundance of the primary endosymbiont, Portiera, increased in females but was unchanged in male whiteflies, while that of the secondary endosymbiont, Hamiltonella, significantly decreased in both male and female whiteflies. The secondary endosymbionts, Cardinium and Rickettsia, were apparently not affected in either male or female whiteflies., Conclusions: The community structure of BABM can be drastically altered following treatment with the antibiotic, rifampicin. This may be due to different antibiotic susceptibilities among the bacterial species. These results provide valuable insights into the innate differences in the BABM of male and female whiteflies, as well as structural changes that occur in the BABM in response to exposure to an antibiotic., (Copyright © 2018. Published by Elsevier B.V.)

Invasive genotypes may be associated with their ability to access the invasion habitat. The whitefly, Bemisia tabaci Q, has been an important agricultural pest in China since 2008. In order to identify the invasion routes and to provide insight into its invasion success in China, we analyzed the composition, distribution, and genetic diversity of mitochondrial haplotypes of B. tabaci Q. Samples were obtained from 23 provincial level administrative units in 2011, and analyses conducted based on the mtCOI. Our results revealed five haplotypes (abbreviated as Q1H1-Q1H5) were present in the Q1 subclade based on 773-bp mtCOI fragment analysis. The diversity of haplotypes indicated the B. tabaci Q populations were derived from multiple invasion sources originating from the western Mediterranean region. Among the haplotypes, Q1H1 was dominant, followed by Q1H2. The whitefly populations were generally characterized by low levels of genetic diversity based on the 773-bp mtCOI fragment. Similar results were obtained when the 657-bp fragment was analyzed using the procedure in a previous report. Potential mechanisms contributing to the dominance of the Q1H1 in China are also discussed. These results will be helpful in revealing the mechanisms that enabled the successful invasion of B. tabaci Q into the country.

In this study, we evaluated the adaptability of the small brown planthopper (SBPH), Laodelphax striatellus (Hemiptera: Delphacidae) to four rice cultivars including Shengdao13 (SD13), Shengdao14 (SD14), Shengdao15 (SD15), and Zixiangnuo (ZXN) using the age-stage, two-sex life table with a simplified method for recording egg production (i.e., every five days vs. daily). The intrinsic rate of increase (r) of the SBPH was the highest (0.1067 d -1 ) on cultivar SD15, which was similar to the rate on SD14 (0.1029 d -1 ), but was significantly higher than that occurring on ZXN (0.0897 d -1 ) and SD13 (0.0802 d -1 ). The differences of the finite rate of increase (λ) on the four rice cultivars were consistent with the r values. Population projection predicted an explosive population growth of the SBPH occurring in a relatively short time when reared on SD14 and SD15. These findings demonstrated that the SBPH can successfully survive on the four rice cultivars, although there were varying host adaptabilities.

Background: Although discrepancy in the specific traits and ecological characteristics of Bemisia tabaci between species are partially attributed to the B. tabaci-associated bacteria, the factors that affect the diversity of B. tabaci-associated bacteria are not well-understood. We used the metagenomic approach to characterize the B. tabaci-associated bacterial community because the approach is an effective tool to identify the bacteria., Methodology and Results: To investigate the effects of the host plant and a virus, tomato yellow leaf curl virus (TYLCV), on the bacterial communities of B. tabaci sibling species B and Q, we analyzed the bacterial communities associated with whitefly B and Q collected from healthy cotton, healthy tomato, and TYLCV-infected tomato. The analysis used miseq-based sequencing of a variable region of the bacterial 16S rDNA gene. For the bacteria associated with B. tabaci, we found that the influence of the host plant species was greater than that of the whitefly cryptic species. With further analysis of host plants infected with the TYLCV, the virus had no significant effects on the B. tabaci-associated bacterial community., Conclusions: The effects of different plant hosts and TYLCV-infection on the diversity of B. tabaci-associated bacterial communities were successfully analyzed in this study. To explain why B. tabaci sibling species with different host ranges differ in performance, the analysis of the bacterial community may be essential to the explanation.

In Liaoning Province, China, tomato yellow leaf curl virus (TYLCV) was first detected in 2009 and in only four counties. To quantify the spread of TYLCV and to identify potential factors influencing its spread in Liaoning Province, we assayed for TYLCV within 1,055 whiteflies (Bemisia tabaci (Gennadius) complex) from 74 populations and 29 counties in 2011. The B. tabaci species of these individuals was determined based on molecular markers. TYLCV was found in 13 counties (Donggang, Liaoyang, Kazuo, Lingyuan, Heishan, Liaozhong, Kaiyuan, Taian, Dawa, Dashiqiao, Beizhen, Linghai, and Xingcheng) and was most frequently detected in the central plain. In addition, the percentage of whiteflies with TYLCV was significantly higher in B. tabaci Q than in B. tabaci B but was unrelated to the hosts (pepper, eggplant, tomato, cucumber, and kidney bean) on which the whiteflies had been collected. These results demonstrate that TYLCV has spread rapidly in Liaoning Province since its first detection and suggest that its spread is more closely associated with the introduction of B. tabaci Q than with the species of host plant. These findings also indicate that controls are now needed to reduce the further spread of TYLCV and that these controls should include the management of B. tabaci Q populations.

Background: Even though introductions of exotic species provide ready-made experiments of rapid evolution, few studies have examined the genetic structure of an exotic species shortly after its initial introduction and subsequent spread. To determine the genetic structure of its populations during the initial introduction, we investigated the invasive sweet potato whitefly (Bemisia tabaci Q, commonly known as B. tabaci biotype Q) in China, which was introduced in approximately 2003. A total of 619 B. tabaci Q individuals in 20 provinces throughout China were collected and analyzed using five microsatellite loci., Results: The introduced populations of B. tabaci Q in China represent eight genetic clusters with different geographic distributions. The populations in Yunnan Province, where B. tabaci Q was first detected, are genetically different from the other populations in China., Conclusion: The introduced populations of B. tabaci Q in China have high spatial genetic heterogeneity. Additional research is required to determine whether the heterogeneity results from multiple introductions, rapid evolution following one or few introductions, or some combination of multiple introductions and rapid evolution. The heterogeneity, however, is inconsistent with a single introduction at Yunnan Province, where B. tabaci Q was first detected, followed by spread.

Background: MicroRNAs (miRNAs) are small, conserved, non-coding RNAs that post-transcriptionally regulate gene expression. Bemisia tabaci (Gennadius) B and Q are two invasive and dominant whiteflies, and B. tabaci Q has been displacing B in China. Differences in biological traits (fecundity, host range, resistance to insecticides, etc.) as affected by miRNAs might be involved in the displacement. In this study, we performed high-throughput sequencing to identify miRNAs in B. tabaci B and Q., Results: We identified 170 conserved miRNAs and 15 novel candidates, and found significant differences in the expression of miRNAs between B. tabaci B and Q., Conclusion: Expression levels of miRNAs differ in B. tabaci B vs. Q. Additional research is needed to determine whether these differences are related to differences in the biology of B. tabaci B and Q, and whether these differences help explain why B. tabaci Q is displacing B in China.

In recent years, the dominant biotype of Bemisia tabaci (Gennadius) has shifted from biotype B to Q in many locations of China. Our field monitoring showed that B. tabaci biotype Q could be found on pepper Capsicum frutescens L. while biotype B could not be found on the plant. To study the role of the host plant in the displacement of biotype B by Q, the adult mortality, female fecundity, and adult emergence of both biotypes B and Q on different host combinations were studied using a model system involving pepper and eggplant. The results showed that pepper is not a preferred host for either biotype B or Q adults in comparison with eggplant. The negative impact of pepper to biotype B is, however, much greater than that to biotype Q. Because both the survival rates of the adult whitefly and the average number of emerged adults per female of biotype Q on pepper are higher than that of biotype B, biotype Q showed higher fitness in comparison with biotype B. Our results suggest that the existence and differential impact of a nonpreferred host might affect the population fitness and therefore could play a role in the displacement of biotype B in some regions.

Bemisia tabaci has caused significant crop losses in China during the last decade. Recent research has shown that two potentially invasive variants, biotypes B and Q, have been found in several regions of China. Our objective was to determine the biotype status and the distribution of B. tabaci in Shandong province, an important agricultural region of China. Based on mitochondrial DNA markers, both biotypes B and Q were detected, with B being the predominant biotype. The results indicate that the more recently introduced biotype Q has not only been located in China but also has established and spread in some regions.