Well, no. But recent research shows that at least some may be able to convert sunlight into energy in a process very similar to the way plants do it.
A study published in Nature magazine back in August looked at a species of aphid called Acyrthosiphon pisum, which changes color based on the air temperature around it. At optimal temperatures, the aphid tends to be orange, but in cooler temperatures, the aphid is more often green. Through a series of experiments, the scientists determined that – as in plants – the pigmentation of those aphids helped them generate energy, and that the green aphids made more of it than the orange ones.
Can aphids make their own energy?
As is usually the case, more research is needed to confirm exactly what’s going on, and to see if other aphid species have the same ability. But these are pretty extraordinary results. The process of converting sunlight to energy is common in plants, of course, but insects and other animals don’t do that – or so we thought.
What the aphids appear to be doing isn’t technically photosynthesis (no carbon dioxide is fixed and converted to organic compounds – I’m just telling you what I read…) but many of the essentials are there. The scientists wonder if the ability helps the aphids survive when they don’t have quick access to food – such as when they’re traveling from one plant to another.
You can read a more complete description of the study here.
The Prairie Ecologist 
Fascinating! Perplexing too, considering Nancy Moran’s comment that aphids often have more sugar than they can process. And my what a bunch of persnickety commentors on the article, geez.
Chris, That is an amazing photograph. Was it difficult to find the aphid and get that clarity on such a small insect? How are you and what’s the most pressing project you’re involved with these days? Thanks, Ed
Hi Ed – thanks. Actually, it’s one of the very few aphid shots I have that I really like, and I’ve taken a lot of them. Aphids are so small that I have a hard time getting the image I want. In this case, I really like the background, and that the aphid stands out against it while still showing that it is nicely camouflaged.
I’m doing great. It’s bittersweet to be coming to the end of another field season, but am hoping to get some things done this winter (I say that every year). No one particular project right now – just lots of things in the air.
Not so terribly persnickety, Inger. Just normal scientific discourse, with a bit of language-style pedantry thrown in. Actually, I was glad for the latter, as I was a bit uncomfortable with the “begs” wording, but couldn’t put a clear reason to it.
You always present thoughts, ideas or facts that I have never considered or been exposed to. Don’t know how you do it, but keep it up. I need to keep my brain churning. (: Thanks