Summary
Scale insects are commonly associated with obligate, intracellular microorganisms which play important roles in complementing their hosts with essential nutrients. Here we characterized the symbiotic system of
Greenisca brachypodii
, a member of the family Eriococcidae. Histological and ultrastructural analyses have indicated that
G. brachypodii
is stably associated with coccoid and rod‐shaped bacteria. Phylogenetic analyses have revealed that the coccoid bacteria represent a sister group to the secondary symbiont of the mealybug
Melanococcus albizziae
, whereas the rod‐shaped symbionts are close relatives of
Arsenophonus
symbionts in insects – to our knowledge, this is the first report of the presence of
Arsenophonus
bacterium in scale insects. As a comparison of 16S and 23S rRNA genes sequences of the
G. brachypodii
coccoid symbiont with other gammaprotebacterial sequences showed only low similarity (∼90%), we propose the name ‘
Candidatus
Kotejella greeniscae’ for its tentative classification. Both symbionts are transovarially transmitted from one generation to the next. The infection takes place in the neck region of the ovariole. The bacteria migrate between follicular cells, as well as through the cytoplasm of those cells to the perivitelline space, where they form a characteristic ‘symbiont ball’. Our findings provide evidence for a polyphyletic origin of symbionts of Eriococcidae.