Slime Moulds
Continuing the theme of species that need deadwood, I thought I would cover some of the most mysterious.
Slime Moulds are strange. I think even those scientists who study them would not disagree with that statement. They strongly resemble fungus in appearance, and turn up in similar sorts of habitats such as damp grassland or on rotting wood. Also like fungus they are essentially invisible for most of the year, hidden away underground, in leaflitter or within the wood itself. When we can see them, they are often brightly coloured and formed of small blobs or web-like shapes all grouped together. However, slime moulds may be slimy but they are not actually moulds at all, they are micro-organisms capable of movement, hunting down the bacteria, fungus and other items they eat as food.
It is towards the end of the Summer and into Autumn that slime moulds become more obvious on the surface of wood, over dead leaves or in patches of grass. They often resemble something rather unpleasant, one species is even known as Dog’s Vomit Slime Mould as it resemble such a thing all caught up in grass, it really doesn’t look like a living thing at all! However, unlike mushrooms, or other unmentionable substances, despite having no brain, this patch of gunk (technically known as plasmodia) is able to move and learn and is even able to make decisions on where to move based on how hungry it is, where they have already been and what risks currently exist. In fact they are so efficient at this they can solve a maze – and choose the shortest route through it too.
Japanese scientists created a model map of the area around Tokyo, put food at each of the train stations in the region and then dropped a slime mould on Tokyo (not the actual Tokyo, the one on the map). Slime moulds do not like light so they lit areas that had mountains and lakes (which are costly to put trains across/ through) then they left the slime mould to do its thing. The network the slime mould then created between all the food ‘stations’ was as efficient and cost effective as what the humans had come up with. Slime moulds can even find the quickest way out of Ikea which is no mean feat.
Fascinatingly, this organism with no brain can learn and then teach others. For example, Slime Moulds do not like salt, they avoid it but if the only way to get to some food is to crawl over salt, after some trial and error they will learn do this. If they then encounter another Slime Mould which has never learned to move over salt they can fuse with it and pass the learning over. They are also able to use chemicals to call over other individuals of the same species to fuse and join in, enlarging the goo. The bigger it is, the faster it can move, reaching a heady top speed of around 1mm an hour.
It is possible to keep slime moulds as a strange sort of pet relatively easily, some species can be happily fed on oat flakes. There’s lots of information on-line. Scientists and planning experts genuinely use slime moulds ‘in captivity’ to help with route planning and decision making and something to do with computers that I don’t really understand (you’re going to have to read on that yourself!). Or you can just keep an eye out for them when out on a walk and marvel at their weirdness, there is a lot more to that strange patch of slimy goo than meets the eye.
Gillian Fisher, Ecologist
Photograph below by kind permission of Alex Prendergast
