Slime Molds Are Earth’s Smallest, Oldest Farmers

Colonies of a bizarre microbial goo have been found practicing agriculture at a scale tinier than any seen before.

Animals such as ants, snails and beetles are known to farm fungus. But the slime mold’s bacterial-farming trick takes it into a whole new realm.


Dictyostelium discoideum, the best-known of a group of creatures called slime molds, spends part of its life as a single-celled amoeba feeding on bacteria that grow in decomposing leaves on forest floors.

When food is short, hundreds of thousands of amoebas come together, fusing into a single entity. It may crawl off as a slug in search of richer pastures, then form a stalk topped by a “fruiting body” that bursts to disperse a few lucky amoebas-turned-spores. Or it may form the stalk right away, without crawling.

It’s been thought that slime molds simply scavenge, eating bacteria they like and oozing out the rest. In laboratories, researchers “cure” slime molds of their bacteria by allowing them to purge themselves on Petri dishes. But researchers kept finding bacteria in the fruiting bodies of some slime molds and not others.

When grown in the lab, the unusual fruiting bodies grew both the slime mold and the bacteria.

The team of scientists took new samples of different slime molds in the wild, growing them with careful attention to their dietary and excretory habits. They found that some strains didn’t gorge themselves and “lick the plate clean” of bacteria, but instead saved some inside of the colony. They were farmers, and fared better in some soils than their nonfarming counterparts.

Read more in the original article here.


Yellow Slime Mold Timelapse from sesotek on Vimeo.