Sometimes nature is so strange, you have to see it to believe it. That’s certainly the case with ant farmers. Some ant species keep teeny little aphid farms. Like human dairy farmers, they protect their animals, herd them to lush pastures, and milk them.
But the “milk” here isn’t milk at all, and there are no udders to be seen. Aphids are itsy-bitsy insects that feed on plant sap, and the byproduct of that feeding is a clear, sugary liquid called honeydew that bubbles out of the aphids’ butts. Ants just can't get enough honeydew.
Mmm, aphid butt juice. Image credit: Dawidi via Wikimedia Commons // CC-BY-SA 3.0
To keep the honeydew flowing, ants set up minuscule aphid farms on juicy plant stalks. They protect their livestock from would-be cattle rustlers like ladybugs, and relocate their herds to greener pastures when the sap is running dry. To induce the aphids to squeeze out their precious fluids, the ants stroke the little bugs’ backs with their antennae.
The arrangement seems pretty idyllic for everyone involved, but scientists say aphids are getting the short end of the stick. Like human farmers, ants are very possessive of their herds and have a vested interest in keeping their livestock on the farm. Researchers have learned that ants’ feet emit a chemical that manipulates aphids into staying put. The ants are also not above biting the wings off any aphid that might attempt escape, nor will they hesitate to gobble up a few aphids here and there.
It isn’t perfect, but what agricultural society is?
Header art by Rebecca O'Connell