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Slime Moulds Get Smart

Image of Tanya

Dr Tanya Latty has never lost her childhood fascination with “creepy crawlies”.

By Stephen Luntz

How can slime moulds make complex decisions when they don’t have a brain?

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Dr Tanya Latty had more encounters with bears than she could count before coming to Australia to study slime moulds. She may now be safer, but her ego could have been dented with her discovery that these masses of brainless cells can be more effective than people at weighing up conflicting options before making optimal decisions.

“How individuals deal with multiple conflicting demands when they are choosing their food is an important aspect of foraging ecology in living things,” says Latty of the University of Sydney’s School of Biological Sciences. “Yet the body of knowledge we have on foraging behaviour has pretty much ignored neurologically simple organisms like the slime moulds.”

Latty has rectified this with the discovery, published in Ecology, that slime moulds can balance the quality of a food source against the level of light exposure. “Slime moulds don’t like too much light – they turn and grow away from areas that are well-lit,” Latty explains.

Slime moulds travel towards a food at 5 cm/hour. Latty offered slime moulds two patches of food with differing amounts of light and food quality (determined by the proportion of oatmeal in agar). The moulds consistently chose the better food in the same light, even if the oatmeal concentrations varied by only 2%. However, when light levels differed the moulds avoided the light unless they were tempted...

The full text of this article can be purchased from Informit.