First Evidence of Intracellular Bacteria Cardinium in Thermophilic Mite Microzetorchestes emeryi (Acari: Oribatida): Molecular Screening of Bacterial Endosymbiont Species

We undertook the issue of the distribution of intracellular bacteria among Oribatida (Acari). Six genera of bacteria were detected by PCR and Sanger DNA sequencing: Wolbachia, Cardinium, Rickettsia, Spiroplasma, Arsenophonus, and Hamiltonella. Our research, for the first time, revealed the presence of Cardinium in Microzetorchestes emeryi in two subpopulations separated from each other by 300 m. The percentages of infected animals were the same in both subpopulations—ca. 20%. The identity of 16S rDNA sequences of Cardinium between these two subpopulations of M. emeryi was 97%. Phylogenetic analysis showed that the Cardinium in M. emeryi was clustered into the group A. The occurrence of M. emeryi in Poland has not been reported before and our report is the first one. Cardinium maybe help the thermophilic M. emeryi to adapt to low temperatures in the Central Europe.