Nice little bit in the New York Times tomorrow about aphids and their symbionts. Henry Fountain writes (Observatory - How Tiny Insects, With a Little Help, Survive on Plant Sap - NYTimes.com) about a new article by Angela Douglas, one of the true pioneers of endosymbiont research. In her study she dissects in fine scale detail which essential amino acids are missing from the aphid sap only diet and which ones are made by the symbionts. Interestingly, the research apparently shows that the aphids may have figured out how to make methionine by themselves. I say apparently since I have been unable to track down the paper which I assume is coming out soon.
I should note, in one of the symbioses like this that I have studied with Nancy Moran we found that there were two symbionts contributing to the nutrition of the host. We found that one of the symbionts was likely making amino acids for the host (an insect called the glassy winged sharpshooter which eats only xylem sap) and the other symbiont was likley making vitamins. Nancy showed later with John McCutcheon that the symbiont that was making vitamins also was predicted to be making methionine for the host. So it seems possible there might be a missing symbiont in the aphid study? Although it would be cool if the aphid has figured out how to make an amino acid most animals are not able to make.
Hat tip to Max Lambert for pointing this out.