Aphids May Harvest Solar Energy Like Plants

By Sophie Bushwick | August 20, 2012 3:13 pm

aphids

Turning the sun’s rays into usable energy is a skill thought to be limited to plants, algae, and solar panels. But a new study suggests that aphids may be also possess this ability.

Aphids already stand out from other animals for their production of carotenoids, pigments that also help out the immune system—most organisms get carotenoids from food, rather than making them themselves. A group of French and Israeli researchers now suggests that the reason aphids expend energy making these pigments is because they play an additional role in aphid life: Carotenoids, which plants use in photosynthesis, could be helping aphids do some of the same tricks.

There are three colors of pea aphids: green, orange, and white. Greens have the most carotenoids and white ones the least. Intriguingly, the researchers found that the green aphids contain the most ATP—a molecular battery that carries energy throughout the body—and white aphids the least.

This suggested to the researchers that perhaps the carotenoids were helping the little bugs capture light energy. To test this hypothesis, they placed some aphids in the dark and let others experience light-dark cycles. They found that at least in the case of orange aphids, those exposed to light manufactured more ATP than those that lived in darkness.

These results are certainly suggestive, but they do not prove that carotenoids help aphids turn sunlight into usable energy. For their next step, researchers may want to engineer aphids with no carotenoids at all and compare them to their pigmented brethren, to find out if these little bugs are really imitating plants.

Image courtesy of Luc Viatour / Wikimedia Commons

CATEGORIZED UNDER: Living World
  • Isabel

    “most organisms get carotenoids from food”

    Do you mean most animals?

  • Joe Terry

    I’d be more interested in ATP/ADP ratios, especially how they change under the experimental conditions.

  • http://www.achworks.com Joe Real

    This is not surprising. There is an animal, a green sea slug, that even does more than these aphids. The animals obtain chloroplasts from the plants that they eat, and then use the chloroplasts for photosynthesis, to supply them with their own food. These animals can do photosynthesis and it keeps them alive without any food. These are considered half-animals and half plants, so could be an entirely separate taxonomic kingdom, just like lichens which are part fungus and part plants in character. It is good to know that to a certain extent, aphids have these ability to use solar energy too. Here’s the old article about a photosynthesizing sea slug:

    http://www.msnbc.msn.com/id/34824610/ns/technology_and_science-science/t/sea-slug-surprise-its-half-plant-half-animal/

  • JeffB

    Not just the green sea slug. Giant clams are photosynthetic, and a great deal of corals are as well. It’s something that aquarium keepers have had to deal with for a long time. Until recently it was very difficult to even get enough light on a coral tank without running up an electric bill that would get you investigated for running a grow op.

  • http://evolutionaryroutes.wordpress.com/ Julius Csotonyi

    Joe Real and JeffB: Although the sea slug _Elysia chlorotica_ sequesters chloroplasts from algae, these chloroplasts can only be maintained temporarily (even though the slug possesses some maintenance genes from the algae that may help keep the chloroplasts alive for a while). Further, a lot of animals and fungi engage in symbiotic relationships with photosynthetic algae or cyanobacteria in order to acquire additional nutrients indirectly via photosynthesis by their symbionts.

    However, there may be a qualitative difference with the aphids. They may be the first known animals to possess enough of the genes needed to encode a functional set of the biochemical machinery of photosynthesis (albeit a truncated form, probably without the complex light harvesting antennae complexes and reaction centers found in plants, algae and photosynthetic bacteria). Hence, these aphids need not rely on a symbiotic partner to perform a form of photosynthesis.

    You can remove a symbiont from the sea slug or coral and the animal will be simply heterotrophic, but the aphid remains (potentially) photosynthetic without any additional symbiont. Among other things, this kind of possession of genes makes the process potentially more stable. Consider that corals, which rely on algae for their photosynthetic capabilities, can “bleach” under certain conditions (meaning that they expel their symbionts, causing the corals to lose their green color, which is due to the pigments of the algae), and without their symbionts, their fitness is reduced.

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