Here’s something that could solve a great deal of humanity’s problems real quick: humans not having to eat so much, or at all. We could stop mowing down the Amazon to plant grains to feed cows, or maybe we could take our collective foot off the neck of the estimated 52 percent of all U.S. land area used for agriculture, and, of course, maybe those 925 million people worldwide considered by the UN to be undernourished would find some relief. Sadly, I’m not about to offer some technological panacea to world hunger — this bit of wishful thinking involves the human organism being able to convert sun energy into glucose energy via photosynthesis. Which it can’t, obviously, but a bit of new research points to the first known members of the animal kingdom that can actually use sunlight for food: aphids.This suggestion comes courtesy of a new paper posted to _Nature_’s open-access journal Scientific Reports. The idea that the pea aphid possibly utilize photosynthesis is based on the finding that the bugs are able to synthesize pigments called carotenoids, a common and necessary thing for many animals (for non-photosynthesis uses, like maintaining a healthy immune system), but one that every other animal must consume from outside sources. Meanwhile, plants, algae, fungi, and bacteria are all quite adept at synthesizing carotenoids themselves, and, in all of those organisms, carotenoids are a key part of photosynthesis. And it would seem that’s what aphids use it for too.A post at nature.com summarizes the basic idea pointing to aphid photosynthesis:When the researchers measured the aphids' levels of ATP — the 'currency' of energy transfer in all living things — the results were striking. Green aphids, which contain high levels of carotenoids, make significantly more ATP than do white ones, which are almost devoid of these pigments. Moreover, ATP production rose when the orange insects — which contain an intermediate amount of carotenoids — were placed in the light, and fell when they were moved into the dark.So, more carotenoids, more energy; more light, more energy. Good work aphids. While study co-author Maria Capovilla cautions that more research is needed before we can determine if aphids are photosynthesizing like non-animals, it does sound an awful lot like photosynthesis is going down in our weirdo insect friends. (The Nature post points out that pea aphids, sap-sucking insects that feed on peas, clover, alfalfa, and broad beans, are capable of other freaky things, like being born pregnant.) The speculation is that, since aphids already consume a diet high in sugar — to the point where they’re usually consuming more than they can use — the photosynthesis process acts as a back-up of sorts, a spare battery. Granted this doesn’t do humanity’s food crisis any good – not yet at least – but it could be one of the more remarkable findings in biology in recent memory.
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