APHID MICROBIOTA. “The microbiota of most aphids is dominated by the γ-proteobacterium Buchnera aphidicola, which provides the aphid with essential amino acids and is required by the insect: aphids experimentally deprived of B. aphidicola by antibiotic treatment (‘aposymbiotic’ aphids) grow very slowly and are reproductively sterile.”
http://rspb.royalsocietypublishing.org/content/275/1634/565.short