the vomit of the mysterious ‘troll cat’…
Found this slime mould in our local forest the other day and, yes, it looks either amazing or disgusting, depending on your point of view. In Finland, it was believed that witches used this to ruin villager’s milk, giving it the name ‘paranvoi’, meaning ‘butter of the familiar spirit’. Other Scandinavian folklore had this down as the vomit of the mysterious ‘troll cat’…
it actually belongs to one of the weirdest animal groups we know
In fact, it’s scientific name is Fuligo septica. Other names it rejoices under are the poetic ‘Flowers of Tan’ and the somewhat less poetic ‘Dog Vomit fungus’. However, it’s certainly not a fungus or a mould – it actually belongs to one of the weirdest animal groups we know.
Slime Mould Lifecycle
sometimes behaves as a single organism, and sometimes as a group of organisms
First off, depending on the stage of its lifecycle, this thing sometimes behaves as a single organism, and sometimes as a group of organisms. They begin as a single celled creature (an amoeba), which travels about in search of food. This can reproduce when it has enough nutrients, but only contains half the amount of DNA needed for reproduction. This strategy allows it to mate when it comes into contact with another slime mould and so maintain genetic diversity. After mating, this species forms a large mass of similar cells which operate and move together as one body (a plasmodium), in search of food. Their food consists of fungi, yeast, but also micro-organisms – so they behave as both decomposers and predators. Eventually, this group of cells transforms into an aethalium – a structure similar to a mushroom, which turns grey and releases reproductive spores which are, in turn dispersed by beetles. These spores eventually hatch into single-celled amoebae, which repeat the lifecycle. The photo appears to show both the plasmodium and the aethalium stages.
Biochemistry and Behaviour
they are even capable of remembering and learning
Slime moulds have some pretty fascinating abilities. If the environment is dry and nutrient-poor, they can go into hibernation. The species above is also known to be able to tolerate relatively huge concentrations of Zinc – concentrations known to be lethal to many other organisms. It also produces chemicals that are strongly antibacterial, help it to detect sunlight and are even active against some forms of cancer. And believe it or not, if parts of the same slime mould are separated, they can detect each other, move and join up again. Researchers have actually found these creatures can move over 1mm a second – about the fastest speed of any microorganism! But it gets even stranger… One lab experiment showed that they are even capable of remembering and learning. A slime mould was allowed to travel through a narrow container in a warm, humid, food rich environment – ideal conditions for their survival and reproduction. However, its environment was then adjusted to become cold and dry – a change that was repeated regularly over various periods of minutes. When it experienced these conditions, it responded by travelling more slowly. And this is the best bit: it soon learned and anticipated many of the patterns – slowing down at the right times, even when the conditions didn’t change (1). This remarkable behaviour in an animal with no nerves, muscles or brain has led to an improved understanding of how intelligence develops in the animal kingdom.
So, a really amazing animal and definitely not dog sick.
(1) Saigusa, Tero, Nakagaki & Kuramoto (2008) Amoebae Anticipate Periodic Events. Physical Review Letters.