How Can ‘Dog’s Vomit’ Have A ‘Hive’ Mind? Enter The Kingdom Of The Slime Moulds

The slime mould Physarum gyrosum on my lawn in summer

The slime mould Physarum gyrosum on my lawn in summer

Truly alien creatures…are all around us” Professor Christopher Reid, University of Sydney

At dawn you could mistake them for vomited curry, something people find disturbing.

They surface during the night, forming moist, sulphur-yellow pools and then tiny stalagmites emerge from them, forming miniature landscapes. As the sizzling Brisbane sun rises their colour quickly fades to pinky cream. After a few minutes they look brownish, like solidified froth on a cappuccino.

Back in the early 16th century Hieronymus Bosch, the artist famous for painting ‘The Garden of Earthly Delights’ (a print hangs in my hallway) was the first person to illustrate twenty two different types of these visitors. In 1753, Linnaeus described five different species.

Gardeners usually mistake them for fungi, but they’re slime moulds, neither fungus, plant, nor animal, but something in between. My species is sometimes called the Dog’s Vomit Slime Mould, Fuligo septica.

It’s a cosmopolitan species, even recorded occurring as far north as Finland. There it was supposed to have been used by witches to spoil milk. It aggravates gardeners in the USA. Apparently in Mexico it’s collected in jars by moonlight, cooked and served like scrambled eggs. But it pays to know your slime moulds, some species are toxic, others yield antibiotics. They’re  part of popular culture, inspiring films like ‘The Blob’, and books like Philip K. Dick’s ‘Clans of the Alphane Moon. A Spinal Tap DVD includes a reference to them…“Well slime moulds are so close to being both plant and animal that it’s like they can’t make up their minds.” David Ivor St. Hubbins, a fictional character in the mockumentary film This Is Spinal Tap (1984).

These organisms are in the Eukaryota, also known as Myxomycetes, and they now have their own kingdom. Starting life as single-cells with just a thin cell wall around them, as they feed they grow, but instead of their cells dividing to produce an aggregation of duplicates, like other life forms, they retain a single cell wall, growing in size, while inside their nuclei multiply. Slime moulds form a plasmodium, the largest undivided cell known to science.

Rather like an amoeba, a plasmodium forms pseudopodia (false arms) which locate, engulf, then digest food. They mostly feed on bacteria, but one species in my garden lives exclusively on grass. Plasmodia travel. Once they’ve cleared an area of food, such as rotting logs, mulch, or well-composted soil, they move to the surface, form sporangia (fruiting bodies) which release reproductive spores. If drought hits, plasmodia form resting  sclerotia which resume growth when there’s sufficient moisture.

The taxonomy of slime moulds is still evolving and remains very much in flux.

This morning I splashed a patch whilst watering, sending clouds of rich brown spores into the air to restart the whole process…

According to a news item in BBC News On Line, Slime moulds use a form of spatial ‘memory’ to navigate: a ‘hive mind’ which I first heard about watching Star Trek! These are very curious life forms indeed, and having witnessed the emergence and behaviour of Dog’s Vomit Slime Mould (Fuligo septica) in my Brisbane garden, I thoroughly agree.

There’s more than a hint of ‘Middle Earth’, when countless millions of the single-celled organisms emerge from rotting bales of sugarcane in my garden.

I was astonished when a grey version (finally identified as Physarum gyrosum on 25.2.15 by an expert in the USA!) streamed up through a patch of lawn grass one summer and morphed and changed colour. Apparently, this species feeds exclusively on grass and five different antibiotics have been isolated from it.

Slime Moulds seem to ‘bloom’ when the summer storm season arrives. Mostly after a storm, when things are moist and steamy. Around sunset, these living pools of life stream up and through the bales. There they form various shapes and harden from a soft, moist and shiny custard-like form into a harder, darker, powdery form. Once the searing morning sunlight hits them, they are merely inanimate dollops of fine powder, ready to waft away in the wind, or by a blast from a hose of water…

Enjoy the full article here: “Brainless slime mould has an external memory”
Ella Davies, Reporter, BBC Nature

Jerry Coleby-Williams
Updated 25th February 2015