Figure 2.

The absence of B. cuenoti in N. australiensis. (a) Light microscopy of a semithin section of fat body tissue of N. australiensis (Donna Cave, Chillagoe, Queensland). No bacteriocytes harbouring endosymbiotic bacteria are evident. Semithin sections from Nocticola sp. (Royal Arch Cave, Chillagoe, Queensland) also revealed the absence of bacteriocytes (data not shown). (b) Fat body section from Periplaneta americana. Arrows indicate prominent bacteriocytes harbouring B. cuenoti, typical of all cockroaches examined prior to this study. (c) Transmission electron microscopic image of the gut lumen of N. australiensis. Numerous prokaryotic forms are visible, suggestive of a diverse microflora.