Variation in Wolbachia host interactions in strains of the two-spotted spider mite, Tetranychus urticae
Breeuwer, J.A.J. and Vala, F.
Institute for Systematics and Ecology, University of Amsterdam Kruislaan 320,
1098 SM Amsterdam, The Netherlands
Wolbachia are vertically transmitted bacteria that can alter host reproduction in several ways. One such way is cytoplasmic incompatibility where crosses between uninfected females and infected males (U x I) yield reduced hybrid production. Wolbachia are widespread in arthropods and were recently described to occur in mites. Previously, we showed that Wolbachia can induce partial cytoplasmic incompatibility in (U x I) crosses in one strain of T. urticae and cause mortality among diploid (female) offspring. Here we investigated whether variation exists in the level of incompatibility between infected and uninfected individuals within three strains of the haplo-diploid phytophagous spider mite Tetranychus urticae. Secondly, the effect of infection on female fecundity (i.e. clutch size) and daughter production were analyzed. F1 expressed incompatibilities were not detected in U x I crosses in the cucumber strain. For the rose strain a significant increase in F1 male production was observed. A significant increase in F2 mortality was also observed among haploid broods of virgin F1 females from (U x I). This effect was absent from the tomato and the cucumber strains. Thus, polymorphism exists with respect to the phenotypic effects of Wolbachia on within strain reproductive compatibilities in this species. With respect to female fecundity, negative effects were associated with infection in both the cucumber and the rose strain. However, in the cucumber strain this is compensated for by decreased F1 mortality and increased daughter production. The effect is such that the total number of offspring produced by infected females does not differ from that of uninfected females and the total number of daughters produced is higher in the former. This is the first report on beneficial effects of Wolbachia infections in female hosts. Finally, we will discuss the consequences of these findings for evolutionary dynamics of Wolbachia-host interactions.
| LOCATION |
DATE |
TIME |
| Lecture Hall I |
Thursday, April 9 |
10:15 am |