Do you remember biology lessons growing up?. I clearly remember  how photosynthesis was a “plant thing”. That was one of the main differences between the animal and the plant kingdom. Another difference was that plants had a green color thanks to photosynthesis.

English: Adult pea aphid on alfalfa

English: Adult pea aphid on alfalfa (Photo credit: Wikipedia)

Recent studies have challenged this universal belief. It seems that there is one insect (Acyrthosiphon pisum) that hold exclusive membership to the Photosynthesis Club.  The first clue is probably its markedly green color in winter. It comes from aphid pigments produced by carotenoid genes, which have been extensively studied and defined in chloroplasts. The carotenoid synthesis that occurs in this insect suggests that this process plays a key role in this insect’s life. Apparently, it possesses a photosynthetic machinery of sorts that interacts with the mitochondria to synthesize ATP, also known as the molecules of energy, so to speak.

From an evolutionary viewpoint horizontal transfer could be responsible for this exciting finding in Acyrthosiphon pisum. Horizontal transfer means that this genetic material was possibly acquired from another organism as opposed to vertical transfer, which means it came from the same species via reproduction. For example, horizontal transfer is the same mechanism used by different bacterial species to acquire antibiotic resistance.

We’ll stay tuned as we wonder if this process takes places in others insects and what its consequences for the metabolic machinery might be.