Hamiltonella and Arsenophonus FISH of T. vaporariorum eggs, nymphs and adults. Secondary symbiont-specific probes for Hamiltonella (green) and Arsenophonus (yellow) were used. A, D and G: FISH of Hamiltonella alone in eggs (A), nymphs (D) and adults (G). B, E and H: FISH of Arsenophonus alone in eggs (B), nymphs (E) and adults (H). C, F and I: double FISH of Hamiltonella and Arsenophonus in eggs (C), nymphs (F) and adults (I).