Localization of the lice symbionts
Both the specific Neisseriaceae and the universal bacterial probes hybridized to bacteria located within DAPI-stained cells (~20-30 μm). In females, these putative bacteriocytes formed weakly adherent clusters found above ovarial ampullae. The two probes did not provide entirely overlapping patterns (Figure 4). However, it is difficult to decide whether this difference is due to presence of two different bacteria within the bacteriocytes or due to the difference in signal intensity produced by chemically distinct chromophores. Many bacteriocytes containing intracellular bacteria were also found in the posterior part of abdomen in male lice (SupplementaryInformation/SupplementaryFigure4).