▪ Abstract Most aphids possess intracellular bacteria of the genus Buchnera. The bacteria
are transmitted vertically via the aphid ovary, and the association is obligate for both
partners: Bacteria-free aphids grow poorly and produce few or no offspring, and Buchnera
are both unknown apart from aphids and apparently unculturable. The symbiosis has a
nutritional basis. Specifically, bacterial provisioning of essential amino acids has been
demonstrated. Nitrogen recycling, however, is not quantitatively important to the nutrition of …