16S rDNA, gyrB , and concatenated ML phylogenies for Cardinium. Sample code (Additional file 1) and host species name in which each strain was detected are indicated: BR=B. rubrioculus; BS=B. sarothamni; PH= P. harti. Two clades are named I and II. ML bootstrap values (top number, bold) and Bayesian posterior probabilities (bottom number, plain) are depicted (only values larger than 50 are indicated). The bar at the bottom indicates a branch length of 10% likelihood distance.