Influence of wolbachia infection on the fitness of the stored-product pest Liposcelis tricolor (Psocoptera: Liposcelididae)

Wolbachia are maternally inherited intracellular bacteria (Rickettsiaceae) that infect a wide range of arthropods and nematodes and that are associated with various reproductive abnormalities in their hosts. In this study, the effects of removal of Wolbachia infection on development, survival, and reproduction of Liposcelis tricolor Badonnel (Psocoptera: Liposcelididae) were investigated in laboratory. The Wolbachia-free strain was obtained by the removal of Wolbachia infection by using 1% rifampicin treatment on the Wolbachia-infected strain (control) for 4 wk, and no Wolbachia gene product was detected in this strain throughout the experiment. The results showed that the removal of Wolbachia infection had negative effects on the fitness of L. tricolor. Compared with the control strain, the Wolbachia-free strain (both in the first [F1] and second [F2] generation) had prolonged developmental times, reduced survivorship of immature stages, and reduced fecundity and longevity, resulting in much smaller rm values. Using rm values, the fitness for Wolbachia-free F1 and F2 relative to the control were calculated as 0.45 and 0.27, respectively. The results of this study further confirmed our previous conclusion that Wolbachia infection have positive effects on fecundity and fertility of L. tricolor, and for optimal reproduction of L. tricolor, Wolbachia must be present in psocids.