High temperatures eliminate Wolbachia, a cytoplasmic incompatibility inducing endosymbiont, from the two-spotted spider mite

Wolbachia can induce cytoplasmic incompatibility (CI) in the arrhenotokous two-spotted spider mite between uninfected females and infected males. Cyto plasmic incompatibility is expressed through a male-biased sex ratio and a low hatchability, and can be suppressed by removing Wolbachia from spider m ites reared on a diet with antibiotics. Here we investigated whether heat-t reatment can elimate Wolbachia from infected mites. Using a PCR assay with a Wolbachia-specific primer pair (ftsZ), and by standard crosses, we were a ble to show that 71 per cent of the mites had lost the Wolbachia infection after rearing the infected population at 32 +/- 0.5 degrees C for four gene rations. The infection could be completely removed when mites were reared a t 32 +/- 0.5 degrees C for six generations. Curing through high temperature s could be one of the reasons why mixed infected/uninfected populations occ ur in the field. An additional consequence of rearing mites at 32 +/- 0.5 d egrees C was the shortened development time. The effect of environmental te mperature on the abundance of Wolbachia and possible behavioural consequenc es for the spider mite are discussed.