We humans (and quite a large number of our fellow mammals) have our head lice, body lice and… lice that may flourish in other regions. It turns out that plants have their own version of lice as well!
Aphids are little bugs that are often very serious pests for agriculture and horticulture. The only redeeming quality, I suppose, is that they’re rather more colourful compared to head lice (and I’m guessing here, mind you,) and come in various shades of yellow, green and brown. Any time you observe odd specks on a plant, tiny blobs stuck to the underside of a leaf or the nodes on stem, in all likelihood they’re aphids. They usually puncture the plant and derive their nutrients from the phloem inside.
Now, aphids are squishy little things, largely defenseless, and can be easy prey for the roving insects, larvae and other fiends. They remind me a lot of herds of sheep, just milling about. You know, if the sheep were yellow, had six legs and a bit more alien.
Like most sheep need sheperds, the aphids need ants! Turns out that humans aren’t the only ones who keep farm animals for food. Ants have been doing it for millions of years now.
Aphids suck up so much delicious juice out of plant veins, that if they try to process all of it, they would all die horrible hyperosmotic deaths thanks to all the high sugar concentrations. To avoid that dreadful fate, aphids secrete out honeydew, manna of the ants and nectar of the arthropods.
Ants carefully collect this honeydew and use it to nourish themselves, and in turn offer the aphids some much needed protection.
More than that, some ants even carry aphid eggs into their nests during winters and keep them safe. Come summer or the monsoon, they bring back the aphid larvae to plants and grasslands where the aphids can graze and the ants can reap their harvest. What a wonderful world.
Metadata Canon Powershot G11. ISO 80. f/2.8 at 1/60 second and f/4.0 at 1/160 second. Edited using Picasa 3.8 and Adobe Photoshop CS5. Taken in August and July 2011 at home and at my workplace respectively, in Bangalore, India.