| Wolbachia and Cardinium are maternally inherited intracellular bacteria that infect a wide range of arthropods and are associated with various reproductive abnormalities in their hosts, causes cytoplasmic incompatibility (CI) in many insect species. So far Cardinium has been found to cause feminization, parthenogenesis, cytoplasmic incompatibility, and be associated with various reproductive abnormalities in their hosts. The whitebacked planthopper, Sogatella furcifera (Horvath) is a major pest of rice in China and various other countries and regions in Asia. Its seasonal northward and southward migrations, landing and endangering abruptly result in serious damage to rice production. In this paper, three different populations of Sogatella furcifera were used as materials; we performed all possible crossing combinations using naturally infected strains to observe the effects of Wolbachia and Cardinium on the reproduction of Sogatella furcifera. We also investigated the fitness costs and/or benefits of infection by each bacterium in the there populations of Sogatella furcifera as a potential explanation for infection frequency of endosymbionts in natural populations (HN, YN, and GX).These results will explain the maintenance and spread of Wolbachia in Sogatella furcifera. Our finding may have implications for the persistence and spread of Wolbachia and/or Cardinium in populations, and will improve our understanding of infection dynamics. In this study we also measured the densities of Cardinium and Wolbachia in adults of different infection status to investigate whether there was a link between the copy numbers of endosymbionts and the strength of CI rescue.We investigated the effects of both Wolbachia and Cardinium, their interactions. In our study the cytoplasmic incompatibility (CI) level was examined, crosses were established by combining doubly infected, singly infected and uninfected planthoppers. This result indicates that singly Cardinium-infected males can induce strong CI and doubly infected males, partial CI, whereas singly Wolbachia-infected males do not induce CI. We compared four possible crosses involving singly infected Cardinium males to investigate in which crosses the induced CI by Cardinium was rescued. Cardinium-induced CI can be rescued in the crosses with Cardinium-infected and doubly-infected females, whereas the rescue of doubly infected females is quite weak.The fitness costs and/or benefits of different infection status in S. furcifera were measured by fecundity of females and developmental duration of nymphs of singly, doubly and uninfected individuals. The effects of different infection types on the developmental duration of nymphs were tested by comparing the development time of each stage of planthoppers. In the HN population Cardinium shortened the time to adulthood of infected individuals. Cardinium-infected individuals reached adulthood significantly earlier than uninfected and doubly infected individuals.The results of Wolbachia and/or Cardinium copy number in males of different infection types showed that Wolbachia and Cardinium density declined with increasing age while the Wolbachia declined rapidly, and we also found that in males singly-infected got the higher endosymbiont density than doubly-infected.In this study we measured the densities of Cardinium and Wolbachia in females of different infection status to investigate whether there was a link between the copy numbers of endosymbionts and the strength of CI rescue. The adults of different infection status of S. furcifera, collected on1,2,4,6,8,10,12,14days old adults. In most stages of adult females, there were more endosymbionts in singly-infected than that of doubly-infected individuals. Comparing the endosymbionts density in doubly-infected adults, Cardinium got significantly higher density than Wolbachia.To our knowledge, this is the first report of the copy number of Cardinium in S. furcifera. |
PDF Full Text Request