(A) Midgut morphology of R. pedestris. The dissected intestine of a third-instar nymph shows the morphologically distinct midgut regions (M1, M2, M3, M4B, and M4), among which the M4B and M4 regions are symbiotic organs. The yellow dashed circle indicates the midgut regions subjected to FISH analysis. (B) FISH analysis of the dissected M4B and M4 regions. The yellow dashed lines indicate the outlines of the M4B and M4 regions. The red signal in the fluorescence image indicates 16S rRNA of the Burkholderia symbiont.