Localization and morphological variation of three bacteriome‐inhabiting symbionts within a planthopper of the genus O liarus ( H emiptera : C ixiidae )

Summary Many planthoppers of the family C ixiidae ( H emiptera : F ulgoroidea ) host three bacteriome‐inhabiting bacteria: a gammaproteobacterium: ‘ C a.   P urcelliella pentastirinorum’, a betaproteobacterium: ‘ C a. Vidania fulgoroidea’, and a member of the bacteroidetes : ‘ C a.   S ulcia muelleri’. Through light microscopy observations, DGGE PCR and FISH analysis, we examined the morphology and localization of these three endosymbionts within the abdomens of females of the planthopper O liarus filicicola . Our results indicate a complex distribution and variation in bacterial morphologies. ‘ C a.   S ulcia muelleri’ singularly colonize one pair of bacteriomes and have cells of irregular shape with an average diameter of approximately 4–5 μm. ‘ C a.   P urcelliella pentastirinorum’ bacteria are roughly globular and have an average diameter of approximately 1.5‐2 μm in a pair of bacteriomes located near the posterior end of the abdomen, which are surrounded by giant and highly degenerated cells of ‘ C a.   V idania fulgoroidea’. In addition, ‘ C a.   V idania fulgoroidea’ colonizes the ‘rectal organ’ ( sensu   B uchner) and the bacterial cells appear as a small, roughly globular with an average diameter of 3 μm; whereas, ‘ C a.   P urcelliella pentastirinorum’ infects an additional two bacteriomes and the bacterial cells appear tightly packed and highly degenerated. All three endosymbionts colocalize in the forming eggs inside the host's ovaries. Based on the abdominal distribution of bacteriomes and bacterial morphologies, we suggest that ‘ C a.   V idania fulgoroidea’ and ‘ C a.   P urcelliella pentastirinorum’ correspond to the symbionts described by Buchner as the ‘ x‐’ and the ‘ c  +  d symbiont’ respectively.