"Nature means necessity."

August 18, 2012 7:36 AM

First Evidence Found for Photosynthesis in Insects: [nature.com] "The biology of aphids is bizarre: they can be born pregnant and males sometimes lack mouths, causing them to die not long after mating. In an addition to their list of anomalies, work published this week indicates that they may also capture sunlight and use the energy for metabolic purposes."
posted by Fizz (26 comments total)

In an addition to their list of anomalies, work published this week indicates that they may also capture sunlight and use the energy for metabolic purposes

You had me at "born pregnant". After that I was ready for anything. Capturing sunlight was the least of my worries.
posted by twoleftfeet at 7:43 AM on August 18, 2012 [2 favorites]

Aphid clones, immaculate conception.
posted by Fizz at 7:55 AM on August 18, 2012

It is easy being green!
posted by fantabulous timewaster at 8:01 AM on August 18, 2012 [5 favorites]

STUPID NATURE STOLE MY IDEA
posted by jscalzi at 8:02 AM on August 18, 2012 [18 favorites]

No. Do not make me appreciate aphids. They are destroying my tomato plant.
posted by maryr at 8:15 AM on August 18, 2012 [4 favorites]

STUPID NATURE STOLE MY IDEA
posted by jscalzi at 11:02 AM on August 18 [+] [!]

Please tell me you have an upcoming book about zombie aphids that create an army of clone ants!!!
posted by Fizz at 8:18 AM on August 18, 2012 [1 favorite]

And please tell me that they're trying to steal the Sun.
posted by Fizz at 8:20 AM on August 18, 2012 [1 favorite]

Please tell me you have an upcoming book about zombie aphids that create an army of clone ants!!!

I do NOW.
posted by jscalzi at 8:22 AM on August 18, 2012 [12 favorites]

I love that over the years every single thing I learned in my biology classes as the hard and fast truth is being proven wrong and more fascinating than originally thought. Here, the truth that only plants engage in photosynthesis, and that is one of the big diffrences between plants and animals. Yay science!
posted by Muddler at 8:23 AM on August 18, 2012 [2 favorites]

No. Do not make me appreciate aphids. They are destroying my tomato plant.

One of the many neat things I learned during one of my attempts to cultivate assorted substances is that while to us ladybugs may look cute and harmless, as far as aphids are concerned they are remorseless killing machines.
posted by Ritchie at 8:44 AM on August 18, 2012 [7 favorites]

Metafilter: may look cute and harmless [...] they are remorseless killing machines.
posted by Fizz at 8:46 AM on August 18, 2012 [1 favorite]

Verrrrry interesting, but I for one am not sold yet. The evidence, and some possible alternative hypotheses:

1. Aphids are green (most carotenoids) under ideal conditions, orange (some carotenoids) when cold, and white (no carotenoids) when resources are scarce. The argument here is that aphids only produce lots of carotenoids when they're basically already fat and happy. This makes some sense as they are expensive compounds to produce, but on the other hand one might expect them to turn to photosynthesis during times when resources are hard to come by instead, as a sort of emergency strategy.
2. Green aphids produce more ATP than white aphids. Here the argument is that because they are photosynthesizing, they are producing more ATP. An alternative explanation might be that they are producing more ATP because white aphids are starving (scarce resources, remember) and their metabolism has switched into resource-conservation mode.
3. Orange aphids, when moved from darkness to light, produce more ATP. This is certainly very suggestive, but the article says nothing about how this compares to the response of white or green aphids. One would expect to see a stronger response in green aphids and a weaker one in white aphids. It is also possible that the increase in ATP production might have something to do with the fact that orange aphids are cold and light is warm, and they might be attempting to capitalize on that warmth by increasing their rate of activity. Also it occurs to me that I produce more ATP in the light than in the dark as well, because when I'm in the dark I'm likely to be sleeping.
4. The carotenoids are present in a layer just under the aphids' cuticles. Again, this is definitely suggestive. However, I don't have to think hard to find a somewhat similar arrangement of light-sensitive molecules in humans which is not photosynthetic: melanin. There is more than one role that surface pigments can play. For instance, the article mentioned that the aphids' color affects their visibility to predators. Aphids live on plants, and it seems plausible to me that green ones probably are going to get eaten less in an environment like that. Perhaps the carotenoids are camouflage, and the aphids are only able to produce it optimally under optimal conditions.

It's still definitely an interesting article. It would be fascinating to discover an animal species that photosynthesizes. It wouldn't be precisely the first animal to do it; corals do photosynthesis, albeit they use symbiotic algae to perform the actual reaction. Still, they are never found without these algae and if the algae die then so do the corals, so it's a very very intimate symbiosis. Aphids would be the first animals to do photosynthesis without an intermediary however, which would certainly be Big News in biology circles.

I also don't think that Nature or the researchers who are named in the article are overselling their findings too badly, which is refreshing. This isn't a published paper, just a Nature News article, and the researchers are quite clear that they are far from ready to say that aphids are photosynthetic. This sort of article definitely serves more of a PR purpose to the lab than anything else (as well as provoking interesting thoughts in those reading it, of course) but good on Dr. Robichon et al for scoring that PR – there's nothing wrong with promoting your research as long as you aren't distorting or exaggerating your findings. It must be exciting times in Dr. Robichon's lab, now that they've found what they have and Nature has taken an interest in it! And it'll be even more exciting if these findings continue to point toward photosynthesis in aphids. But it's worth repeating that at the moment the evidence is at best suggestive, rather than even properly supportive of the hypothesis. It's tantalizing, and merits followup (which I'm sure is what is happening as I write this) but there's nothing strong yet and there are a great many other directions that the evidence could point in as the research continues. That's science, though.
posted by Scientist at 9:05 AM on August 18, 2012 [14 favorites]

That's weird. I was just wondering about aphids the other day.
posted by DaddyNewt at 9:31 AM on August 18, 2012

jscalzi: include altruistic termite suicide bombers living in an air-conditioned mound.
posted by the man of twists and turns at 9:49 AM on August 18, 2012 [1 favorite]

You know who else was capable of photosynthesizing pigments and vitamins?

You.



(Also, Hitler.)
posted by Sys Rq at 10:16 AM on August 18, 2012 [4 favorites]

Interesting. A couple of things puzzled me, though: according to the article, aphids under optimal conditions are orange, not green (green = cold), and aphids get more sugar in their diet than they can use, so energy production doesn't seem to be their biggest concern. (Simple sugars are the preferred fuel for ATP synthesis in most organisms.)

It wasn't clear to me whether green aphids make more ATP than orange aphids, and whether they respond to light the same way. Also, if it's possible to manipulate their diet to provide various amounts of sugar (and I'm not sure how you'd do this with ordinary plant leaves), does that affect the amount of ATP produced?

A bit off topic but here's a cool thing I just found: there's a North American species of "solar-powered" sea slug, Elysia chlorotica, that harvests chloroplasts from the algae it eats and stores those organelles in its own cells, where they keep on photosynthesizing for the slug's benefit. Symbiosis is one of most amazing yet profoundly creepy things in nature. (I'm faintly horrified by my own mitochondria, actually.)
posted by Quietgal at 10:18 AM on August 18, 2012 [2 favorites]

optimal conditions are orange, not green (green = cold)

D'oh
posted by Scientist at 10:19 AM on August 18, 2012

I don't have to think hard to find a somewhat similar arrangement of light-sensitive molecules in humans which is not photosynthetic: melanin

Actually, there is some evidence that melanin can photosynthesize, and possibly even does so in some fungi. But your point, that the best place to put a pigment is about the same whether it's there for coloration or photosynthesis, holds.

The strongest argument against this, I think, is the one mentioned by the researcher quoted near the end of the article (and by my biologist SO as soon as I started reading the article to her): aphids don't really need to photosynthesize, since they usually have more sugar than they know what to do with; what they're short on is amino acids and such. But maybe that's why they tested the orange-presumably-stressed aphids?
posted by hattifattener at 10:20 AM on August 18, 2012

It's been done, sorta
posted by kersplunk at 11:18 AM on August 18, 2012

Ladybug salad.
posted by smidgen at 12:08 PM on August 18, 2012

They need to expose the aphids to isotopically labeled CO2 to prove that the CO2 is being broken down by photosynthesis. Until then, this is merely intriuging.
posted by monotreme at 12:16 PM on August 18, 2012 [3 favorites]

They are PC if they eat only meat.
posted by mule98J at 12:19 PM on August 18, 2012

Damn monotreme, that is exactly what you'd want to do. Wouldn't be too hard of an experiment either, it's practically something you could do at home if you had the radioactive CO2 and a geiger counter.
posted by Scientist at 12:52 PM on August 18, 2012

you could do at home if you had the radioactive CO2 and a geiger counter

Who doesn't, these days?
posted by axiom at 1:05 PM on August 18, 2012

axiom: "you could do at home if you had the radioactive CO2 and a geiger counter

Who doesn't, these days?"

Well it is the future, after all!
posted by symbioid at 2:16 PM on August 18, 2012

> altruistic termite suicide bombers

from the article:"Beware the blue.... if the scientists removed the blue crystal from the termites, their secretions were no longer toxic."
posted by morganw at 8:53 PM on August 18, 2012